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HomeMy WebLinkAboutCC RESO 15,461RESOLUTION NO. 15,461 RESOLUTION OF THE CITY COUNCIL OF THE CITY OF NATIONAL CITY ADOPTING A POLICY FOR THE INSTALLATION Of BICYCLE DETECTION LOOPS AT THE SIGNALIZED INTERSECTIONS IN THE CITY (T.S.C. Item No. 87-62) BE IT RESOLVED by the City Council of the City of National City, California, that there is hereby adopted a policy for the installation of bicycle detection loops at the signalized intersections in the City of National City, which policy is set forth in the City of San Diego Traffic Signal Bicycle Detection Study, dated November, 1985. A copy of said study is attached hereto as Exhibit "A" and incorporated herein by reference. PASSED and ADOPTED this 1st day of December, 1987. GE H( WATERS, MAY R ATTEST: / mom ION CAMPBELL, CITE CLERK APPROVED AS TO FORM: GEORGE H. EISER, III CITY ATTORNEY CITY OF SAN DIEGO TRAFFIC SIGNAL BICYCLE DETECTION STUDY FINAL REPORT _, 1 1 TRAFFIC SIGNAL BICYCLE DETECTION STUDY 1 1 1 November 1985 1 1 1 1 1 1 1 1 1 FINAL REPORT Prepared for CITY OF SAN DIEGO MOHLE, GROVER ' ASSOCIATES G 901 East Imperial Highway Suite A La Habra, CA 90631 • (714)738.3471 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 - TABLE OF CONTENTS PAGE PARTICIPANTS i EXECUTIVE SUMMARY ii INTRODUCTION 1 INITIAL PROJECT MEETING 2 DEFINITION OF PROJECT OBJECTIVES AND GOALS 4 BICYCLE DETECTION STRATEGIES CURRENTLY IN USE 5 BICYCLE DETECTOR ANALYSES 15 COMBINATION BICYCLE/VEHICLE DETECTOR SYSTEMS 25 BICYCLE DETECTOR LOCATION ANALYSIS 26 INVESTIGATION OF DETECTION DEVICES ON BICYCLES 29 INTERIM BICYCLE DETECTION IMPROVEMENTS 30 POLICY DETERMINATION AND RECOMMENDATIONS 32 GLOSSARY OF TERMS BIBLIOGRAPHY 1 1 1 1 1 i 1 1 1 1 1 1 1 1 1 1 1 LIST OF EXHIBITS PAGE EXHIBIT 1 - Recommended Caltrans Loop Types for Bicycle Detection 6 EXHIBIT 2 - Specification of Bicycle Timer 9 EXHIBIT 3 - Loop Marking Used in San Luis Obispo 11 EXHIBIT 4 - Loop Marking Used in Clarke County, GA 12 EXHIBIT 5 - Loop Marking Used in Cupertino 13. EXHIBIT 6 - Recommended Loop Markings 14 EXHIBIT 7 - Measured Frequencies and Inductance 18 EXHIBIT 8 - Measured Frequencies and Inductance 19 EXHIBIT 9 - Cupertino Bicycle Detection Project 1983 20 EXHIBIT 10 - Caltrans Sensitivity Levels 21 EXHIBIT 11 - Specification of Inductive Loop Detectors 24 EXHIBIT 12 - Suggested Detector Distances From Stop Line 27 EXHIBIT 13 - Costs of Interim Measures 31 EXHIBIT 14 - Sample Signal Timing Chart with Sensitivity Values 34 1 1 1 1 1 1 1 1 11 1 1 PARTICIPANTS Prepared for THE CITY OF SAN DIEGO ENGINEERING & DEVELOPMENT DEPARTMENT TRANSPORTATION & TRAFFIC ENGINEERING DIVISION John C. Tsiknas, Senior Traffic Engineer Larry R. Legrand, Associate Traffic Engineer Michael E. Jackson, Bicycle Coordinator William E. Smith, Associate Traffic Engineer THE SAN DIEGO ASSOCIATION OF GOVERNMENTS BICYCLE SUBCOMMITTEE Steven Gottlieb Gordon Shields Ed Reilly Prepared by MOHLE, GROVER & ASSOCIATES R. Henry Mohle, President Albert L. Grover, Executive Vice President Glenn M. Grigg, Project Manager 1 1 1 1 1 1 1 1 1 1 1 EXECUTIVE SUMMARY The purpose of this study was to evaluate various traffic signal bicycle detection schemes and to select a scheme for the City of San Diego that will be practical from the point of view of retrofitting existing signals and adaption to new signal construction. The objective was to adequately answer the City of San Diego's needs for bicycle detection at traffic signals. The study made maximum utilization of existing knowledge concerning traffic signal bicycle detection and used this knowledge in the formulation of a bicycle detection strategy that can be adopted from a practical point of view by the City. The study evaluated various existing bicycle detec- tion strategies and recommends a specific scheme that the City should utilize. The recommended detector types are State standard types already in existence (see Exhibit 1). The key to successful bicycle detection is to use the right type for a given location and to properly adjust the electronic sensitivity of the unit. Details are provided in the report.' A brief summary of the recommendations follows: o On an interim basis, adjust the sensitivity of existing detectors and install pedestrian push buttons in certain cases. o All new traffic signal system designs should specifically address the need to service bicycle traffic and the means by which this is to be accomplished. Vehicle detectors should be designed so that they are sensitive enough to detect all traffic, including bicycles, and detectors for the exclusive use of bicycles should be installed in bike lane approaches to the intersections. The incremental cost of adding these features is so small as compared to the overall project costs that their addition should be a design feature that satisfies the City's policy. o Type D (modified quadrupole) and Type Q (quadrupole) detector loops should be the standard configurations to be used alone or in combination with Type A loops. Left turn lanes and minor side street applications should use State Type 5DA loop ii 1 1 1 1 1 1 1 1 1 1 1 1 installations. Through traffic lanes that are shared by motor vehicles and bicycles should use Type D (modified quadrupole) loops. Detectors at .the stop line that are used for presence or calling purposes are considered to be shared detectors. Advance detectors on arterials will not be expected to be shared by bicyclists; therefore, Type A loops are recommended. Bike lanes that require narrow areas of detection and sharp cut- off properties should use Type Q (quadrupole) loops. o Pedestrian push buttons should only be used in locations where it is not possible to reliably detect the presence of bicycle traffic or as an interim measure to ensure safe passage of bicycles until adequate detection systems can be installed. o Inductive loops should be marked at locations where the sensitivity is critical or where detec- tion is not reliably achieved when the bicyclists ride in the approach lane in a position that is appropriate. o The City should apply for and use TDA (Transporta- tion Development Act) Article 3 funds to implement bicycle related facilities improvements that qual- ify. Other funds should also be obligated to facilities improvements; however, TDA funding should be used first to reduce the impacts of bicycle improvements on the General Funds or Gas Tax Funds. o Detector sensitivity levels could be added to the traffic signal timing charts so that the regular maintenance personnel can maintain the required sensitivity levels as a routine procedure. iii 1 1 1 11 1 1 1 1 1 1 1 1 1 1 INTRODUCTION This report has been prepared for the City of San Diego by MGA, Inc., Municipal and Transportation Engineering Consultants, to resolve problems associated with detecting bicycles at traffic signal systems within the City. The City has expressed a strong desire to resolve these problems and make the traffic signal systems responsive to the bicyclists' needs. To achieve this, the City applied for funding to sponsor this study. The purpose of this study is to investigate the existing traffic signal systems and policies in regard to detecting bicycle traffic at existing and future traffic signals. Current practices of other agencies have been investigated along with results of their efforts and have been reported. The technical means required to reliably detect bicycles have also been investigated and .docu- mented. The means for engineers to initially design systems that will reliably detect bicycles has also been documented. Cost estimates are provided for hardware required to retrofit the existing systems as well as costs of incremental differences between detector systems in use and those designed to detect bicycles. Policy statements are provided for the City of San Diego to ensure that, upon their adoption, bicycle traffic will be considered in all future traffic signal designs as well as in current and future retrofit programs. This project was made possible through the close cooperation of the City of San Diego, the San Diego Association of Governments (SANDAG) and their Bicycle Subcommittee. We appreciate their efforts, individually and collectively, without which this report would not be possible. Funding was provided through the Transportation Development Act (TDA Article 3) from funds set aside for pedestrian and bicycle facilities studies and construc- tion. The opinions, conclusions and recommendations expressed in this report are those of the authors and not necessarily those of the City of San Diego, the San Diego Association of Governments or the Federal Highway Administration. 1 1 1 1 1 1 1 1 1 1 1 1 INITIAL PROJECT MEETING The initial meeting of the consultant team, the City staff and representatives of the SANDAG subcommittee on bicycle facilities was held on July 23, 1985. The concerns, background and other relevant data that is available, in either documentary form or verbal comments from the City staff and other representatives, concerning this study were discussed. The meeting was attended by Larry Legrand, John Tsiknas and Bill Smith of the City of San Diego; by Steven Gottlieb and Gordon Shields representing the SANDAG sub- committee on bicycle facilities and local bicycle inter- ests; and by Hank Mohle, Al Grover and Glenn Grigg of MGA. The following points summarize the primary concerns of the City staff and bicycle interests (not necessarily in order of importance): o Bicyclists should enjoy the rights and privileges of a motorist as provided for in the California Vehicle Code and be subject, of course, to all of the duties and responsibilities thereof. o Existing traffic signal systems in San Diego should be made responsive to bicycle traffic in much the same manner as they are responsive to motor vehicle traffic. o The City does not currently provide specific detection systems for bicycles except in rare instances. o The City has a major investment in the existing traffic signal systems that cannot be discarded or abandoned. o Financing changes in the traffic signal systems to accommodate bicycles is not regarded as a major problem; however, prudent fiscal policies should be observed. o Efficiency of the the traffic signal system is very important to the City; therefore, modifica- tions to these systems should be made with acces- sibility to bicyclists and efficiency in mind. o Changes in the traffic signal systems to enhance their usefulness by bicycles should not be made at the expense of the majority of road users. 2 1 1 1 1 1 1 1 1 1 o The bicyclists, representing SANDAG and local bicyclists' interests, suggested the following possible ways of achieving the equity that they desire: - Make the traffic signals responsive to bicycle traffic. - Add some device to the bicycle to make it easier to detect at traffic signals. - dark the detectors at the intersections so that the bicyclists will know where to ride in order to activate the signal. 1 3 1 • 1 1 1 1 1 1 1 DEFINITION OF PROJECT OBJECTIVES AND GOALS The results of the initial meeting and subsequent meetings on the working papers indicated that our original scope of work was a viable outline of the tasks to be accomplished. The working papers have defined, for the record, the specific results that are to be achieved by this study. They will be used to determine the extent to which this report has satisfied the various tasks of the study. Those objectives and goals are: o A discussion of the various strategies currently in use. o A discussion of types of including sensor units,with field test results. bicycle detection bicycle detectors, bicycle sensitivity o A discussion of types of bicycle/vehicle detectors, including sensor units, with sensitivity field test results for both bicycles and high -bed vehicles. o A discussion of bicycle detector locations based upon bicycle stopping distances and possible conflicts with other vehicles. The discussion should also include any need to provide carryover (extension time) for bicycle detection. o A discussion on the possibility of installing a device on bicycles which would improve detection (magnetic tape, etc.). o A discussion of possible interim measures that could be utilized to improve the detection of bicycles at existing signalized intersections, including costs (marking detectors, etc.). o Development of a policy for the installation of bicycle detection, including costs, based upon the results of this study. The policy should cover both new signal installations and retrofitting existing signalized intersections. 4 1 3 1 1 1 1 1 1 1 1 1 1 1 1 BICYCLE DETECTION STRATEGIES CURRENTLY IN USE There are a number of jurisdictions, Cities, Counties and States, that employ strategies to either detect the presence of bicycles at traffic signals or provide some other means by which the bicyclists can effect the operation of the signal so that the right-of-way can be transferred to the approach that they are using. The more prominent ones are as follows. Inductive Loop Detectors Existing loop detectors and detector amplifiers are being used to detect bicycles in traffic lanes and in left turn only lanes. Although this is technically achievable and can be done quite reliably, it depends upon the proper design and location of the loop and proper placement of the bicycle on the loop detector. This requires some knowledge of the location of the detector and how it works by the bicyclist. As an example, a square loop, Caltrans Type A (Exhibit 1), should be ridden over about three (3) feet to the left or right of the center of the lane while a quadrupole detector (Type Q) should be ridden over in the center of the lane. Where there are bike lanes, detectors are being placed in them where the bicycle is expected to ride. The area to be detected is confined and reliable detection is achievable. Sometimes these detectors are marked with a symbol to give added guidance to the bicyclists. Pedestrian Push Buttons Pedestrian push buttons are currently being used by bicyclists in the State of California by the Cities of Davis, Cupertino, Santa Cruz, Sunnyvale, Huntington Beach and others too numerous to mention. They are installed on the cross street facing the traffic or bike lanes for use by bicyclists desiring to cross the major street or in the left turn only lanes facing the bicyclists wishing to make left turns from those lanes. In general, the push button "calls" the pedestrian interval timing for the phase to be used. The advantage of this is that the bicyclist is guaranteed the same amount of time that a pedestrian would get, provided of course that the button is used. The disadvantage is that most bicyclists require less time to cross than a pedestrian and some efficiency of operation is lost. There are cases where the phase being used does not have a pedestrian signal associated with it, as with the left turn only lane and some split side street phasing 5 7YPE A EXHIBIT 1 0/2ECT/ON dF r T,2AVEL (TM TYPE D RECOMMENDED CALTRANS LOOP TYPES FOR BICYCLE DETECTION 7YPE Q NOTE: SEE CALTRAA/5 STANGp4K0 PL4N5 DATED ✓MY /984 PP 2/0 AND 2//. 1 configurations. In these instances the pedestrian timing features of the controller can be used to provide additional start up and gap times for the bicyclists that are more than that provided for motor vehicles and less than what would be required for pedestrians, thus provid- ing better efficiency. In some cases an unused compatible phase is available for actuation by a bike button or bicycle detector. In these cases the original phase can provide standard vehicle and/or pedestrian timing and the compatible phase can provide the timing required by bicyclists. The City of Sunnyvale uses a device they call a bicycle timer to provide a minimum time for bicyclists that is greater than the vehicle minimum and shorter than the pedestrian interval. A sample specification is included in Exhibit 2. Their device is currently activated by push buttons and will respond to the bicyclists' needs even when the signal is already timing the green interval of a phase. One device is used in the traffic signal cabinet and contains four (4) channels or phases of operation. This device can also be activated by an inductive loop detector or any equipment that provides a contact closure. The cost of pedestrian push buttons is very low and no additional controller equipment is required. Theoreti- cally speaking, if a pedestrian can be trained to push the button, then a bicyclist, with apparently more skill by virtue of the fact that he/she hasn't fallen down, can also. The obvious flaw to this theory is that too many pedestrians don't bother to push the button before cros- sing the street and bicyclists' behavior can probably be expected to be similar. Pedestrian push buttons, in spite of their intrinsic value, should be regarded as supplements to adequate detector systems not replacements for them. As an example, a push button in a left turn only lane is a valuable aid to the bicyclist; however, in order to reach the button, the bicyclist is placed to the left of the lane allowing motor vehicle traffic to pass on the right. When the light turns green, the bicyclist must cross from the left of this lane, through the motor vehicle traffic, to the right side of the roadway to which the turn is made. With adequate detection the bicyclist would be in a better position in the lane to make the left turn. Push buttons on the right side of the roadway should be placed far enough in advance of the stop line so that the bicyclists desiring to go straight across can activate the signal and then move safely to the left of right turning vehicles. 7 1 1 1 I 1 1 1 1 Marking of Loop Detectors Marking schemes are being employed by the Cities of San Luis Obispo, Cupertino, Palo Alto, Eugene and Boulder and by the Counties of Clarke County, Georgia and Santa Barbara. Some are self evident while others require a supplementary sign to describe what the marks on the pavement stand for (see Exhibits 3, 4 and 5 for typical examples). Any detector marking scheme employed should be self evident, requiring no additional signing or informa- tion. It should be obvious to the bicyclists, as well as the motorists, what the symbol stands for and should not be in conflict with or be confused with other standard pavement markings or legends. The marking schemes of Clarke County, Santa Barbara County and the City of Boulder employ signs as a supplement. None of these marking designs has a symbol of a bicycle in it. The City of Cupertino experimented with arrow markings, that were one-fourth (25%) the size of standard pavement legends, placed on the detectors where detection of bicycles was assured. A review of timelapse films, taken before and after, shows no evidence that the bicyclists understood the purpose of the markings. From this we conclude that the most understood markings contain a bicycle symbol as do the markings in San Luis Obispo and the later design in Cupertino. Neither of these markings is supplemented by signs. The symbol should be simple in design, easy to paint and repaint without blurring the image and reasonably inexpensive. We are recommending the symbol in "Standard Alphabets for Highway Signs and Pavement Markings" published by the U. S. Department of Transportation (Exhibit 6). This symbol appears to meet the criteria for simplicity and clarity. In addition, it seems to us that this will be the symbol that will eventually replace the word messages in standard bike lane designs. It also resembles the symbol for bicycling used in the Olympic Games which gives it an added recognition factor. 8 1 1 1 1 1 1 1 1 1 1 1 1 1 EXHIBIT 2 SPECIFICATION OF BICYCLE TIMER MECHANICAL DESIGN Each Bicycle Timer shall be completely enclosed in a sheet metal case with a protective paint finish or be card rack mounted with a standard four and one-half (4-1/2) inch high by "eight (8) inch deep size for use with a Caltrans Model 170 controller. The design shall provide convenient access to the entire interior assembly and permit removal of printed circuit boards or modules with a minimum use of tools. Manually variable timing controls shall be arranged on the front panel. The phase(s) to be affected by this timer shall be clearly and permanently marked on the front panel. Two (2) sets of indicator lights shall also be provided on the front panel. One (1) set shall be used to indicate that a call has been registered from a detector or push button. The second set of lights shall indicate that the Bicycle Timer is timing the interval for bicycle extension. The Bicycle Timer shall provide for the logic to time four (4) separate intervals to be associated with up to four (4) separate phases (phases 2, 4, 6 and 8 in most cases). The intervals shall be adjustable from zero (0) to thirty-one (31) seconds in one (1) second increments. FUNCTION When a bicycle loop detector or bike push button has been actuated, the Bicycle Timer shall operate in the following manner: o For calls received during the yellow or red inter- vals of a phase called, the logic will place and hold a vehicle call until the start of the next green interval for that phase. At the start of the next green interval, the vehicle call shall con- tinue to be held until the expiration of the time set for that phase. o For calls received during the green interval of the phase called, the Bicycle Timer shall begin timing immediately and place and hold a vehicle call until the expiration of the time set for that phase provided that bicycle timing has not pre- viously occurred during that same green interval. 9 1 o Bicycle actuations received during the green interval while the bicycle timing is in effect, or after the bicycle timing has been completed, will not be remembered or carried over to the next cycle. 10 1 1 1 1 1 1 1 1 1 1 1 1 1 1 EXHIBIT 3 ic)% tg4 ttii • LOOP MARKING USED IN SAN LUIS OBISPO 11 1 1 1 1 1 1 1 1 1 1 1 1 1 EX/677N6 5TOP BAR -1 i • • • .41 • r- EXHIBIT 4 LOOP MARKING USED IN CLARK COUNTY, GA. EXIST/N6 CUR6 12 1 1 1 t 1 1 1 1 1 1 1 1 • 1 1 1 1 13 1 1 1 1 1 1 1 1 1 1 1. 1 1 1 1 1 4 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 BICYCLE DETECTOR ANALYSES The most prevalent types of traffic signal detector systems are magnetic detectors, magnetometer detectors and inductive loop detectors. Adler's horn, despite its popu- larity in the early days of actuated signal control, is not one of these. Pressure sensitive detectors, radar detectors and ultrasonic detectors have all gone the way of Adler's horn because of reliability, economic and main- tenance reasons. Magnetic Detectors The magnetic detector is the least used of the three predominant types due to the fact that long term presence mode detection is not possible with this system. These detectors function very well when pulse detection is required in uses such as traffic counting and speed trap measurements. For these reasons the magnetic detector is not one to be considered for detecting bicycles. We are not recommending that the use of this system be attempted. Magnetometer Detectors Magnetometer detectors will perform as well as inductive loop detectors. All of the features of the inductive loop detector are available such as long, medium and short term presence and various sensitivity levels. These systems, in fact, have no real faults and only one (1) serious limitation. The area of detection is confined around the detector probe and the number of probes per amplifier channel is limited to two (2). For motor vehicle detection it is generally acceptable to place two (2) probes in a traffic lane. This makes the magnetometer detector competitive functionally and economically with the inductive loop. However,in order to adequately cover a lane for detecting bicycles, three (3) or four (4) probes should be used. This requires two (2) amplifiers and additional probes to detect one (1) lane. At this point the magnetometer is not as cost effective as the inductive loop. There will always be special occasions where the magnetometer detector will be advantageous to use. Detection on top of or even underneath bridge structures are such locations. We are recommending that magnetometer detectors be considered for use in special situations where the inductive loop itself could cause structural problems or where reinforcing steel or steel beams might shield the effects of the inductance shift required to detect bicycles and/or vehicles. 15 1 • k 1 1 1 1 1 1 i 1 1 1 1 Inductive Loops The inductive loop detector is by far the most - popular detection system in America and in Europe. This system is being used to detect vehicles of all description from bicycles to the largest of trucks. Therefore, this is the system that will be discussed in the greatest detail and is the one that we are recommending for the City of San Diego. There are three (3) basic elements to inductive loop detector systems: the loop(s), the lead-in cable and the detector amplifier. The loop is essentially an air core inductor or coil, the lead-in cable is the connector between the loop and detector amplifier that supplies power to the loop and transmits changes in inductance to the detector amplifier. The detector amplifier senses changes in the inductance of the loop and provides the switch closure to indicate to the traffic signal control- ler that a vehicle is present. The basics of the system are that when any vehicle enters the area of influence of the air core inductor, it creates eddy currents. The eddy Cri(egLar currents cause changes in the electrical properties of the loop. These changes are measured and, if they are of a sufficient magnitude, the equipment creates the switch closure to activate the traffic signal controller. Loops come in all varieties of size, shape and number of turns of wire in them. The number of turns and size of wire will determine the sensitivity of the loop and its ability to detect bicycles. The magnetic fields (effective sensitivity) of the loop increase with the number of turns. This is too easy. To detect small vehicles or bicycles, simply increase the number of turns in the coil. Well, it isn't so easy as there are limitations at both ends of the spectrum. There must be enough wire in the ground to detect the bicycle but the inductance of the combination of the loop and lead-in cable must fall within the range of limitation of the detector amplifier (30 to 700 Microhenries typically, although some have low limits of zero (0) Mh and high limits of 2,000 Mh). In addition, there are operation problems to consider such as adjacent lane detection. From a practicalpoint of view we gener- ally see that the loop will have from two (2) to four (4) turns of wire. Generally speaking, a detector will detect to a height above the pavement of one-half the width of the loop. This means that a six (6) foot wide loop will detect to about three (3) feet above the surface. The statement is generally true of quadrupole loops with the reservation that sensitivity on the center wires is approximately three (3) times that of its edges. A six (6) foot wide quadrupole loop is essentially two (2) loops, three (3) feet wide with a common edge (the center). This loop will 16 1 1 1 1 1 1 1 1 1 1 1 detect approximately one and one-half (1-1/2) feet above the pavement surface except on the center wires where the height of detection is slightly higher. The standard width of a typical inductive loop was not selected arbitrarily but was deliberately set at six (6) feet to coincide with the width of standard size automobiles. Eddy currents generated in the relatively flat sides of the automobile have their own magnetic fields with polarity opposite that of the loop. The result is partial cancellation of the magnetic fields of the loop and a result is a decrease in inductance. Eddy currents in vehicles in adjacent lanes can cause detection when the vehicle is too close to a highly sensitive loop. This problem is more pronounced when a large flat sided truck, such as a furniture van, is in that adjacent lane. The inductance of the loop is vital to its sens- itivity and therefore to its ability to detect bicycles. Relatively high inductance values in the loop will allow lower sensitivity levels to be used on the amplifier. The inductance of an existing loop can be measured using an instrument costing less than $360.00. Exhibits 7-10 illus- trate typical measurements and calculations on existing detectors. The frequency of the loop or loop lead-in combination is measured and the inductance in Microhenries is 372,500 divided by the square of frequency in Kilohertz (372,500/(f*f)). You can also determine the number of turns of wire that was actually installed by the contrac- tor or maintenance person with the formulas listed below. This information, added to the inductance of the lead-in cable, to be discussed below, will let you know if the limitations of the amplifier have been violated. By calculating the inductance, using the formula for square or rectangular loops L=P/4*((Nfr+N) where induc- tance in Microhenries is the perimeter of the loop in feet,' divided by four, times the sum of the number of turns of wire squared plus the number of turns of wire, you can design a loop system that meets the parameters required to detect bicycles. The formula for calculating the inductance of a quadrupole loop is the perimeter in feet times a constant plus the length of the center spoke in feet times a constant(L=P*K+C*K). CONSTANTS FOR LOOP INDUCTANCE CALCULATIONS No. of Turns Constant(K) 1 0.5 2 1.5 3 3.0 4 5.0 17 1 1 1 1 1 1 1 1 1 1 1 i EXHIBIT 7 MEASURED FREQUENCIES AND INDUCTANCE ON VARIOUS BICYCLE DETECTORS IN THE CITY OF CUPERTINO BICYCLE ON CENTER WIRES OF QUADRUPOLE BIKE DETECTOR INDUCTANCE INDUCTANCE LOOP SIZE NUMBER LEAD-IN MEASURED MEASURED MEASURED MEASURED SHIFT IN % SHIFT TOTAL LOOP TYP IN FEET OF TURNS LENGTH FREQUENCY INDUCTANCE FREQUENCY INDUCTANCE OF TOTAL NANOHENRIES + + + + + + + + + + + QUADRUPOLE 2.0 x 10 2 25ft 61114 Hz 99.7 uH 61262 Hz 99.3 uH .483 X 481 QUADRUPOLE 2.8 x 10 2 25ft 61573 Hz 98.3 uH 61783 Hz 97.6 uH .679 % 667 QUADRUPOLE 2.9 x 10 2 25ft 65806 Hz 86.0 uH 66096 Hz 85.3 uH .876 X 753 QUADRUPOLE 2.4 x 10 2 80ft 56333 Hz 117.4 uH 56494 Hz 116.7 uH .569 % 668 QUADRUPOLE 3.6 x 10 2 80ft 58400 Hz 109.2 uH 58621 Hz 108.4 uH .753 % 822 QUADRUPOLE 2.3 x 10 2 100ft 61647 Hz 98.0 uH 61877 Hz 97.3 uH .742 % 727 QUADRUPOLE 2.0 x 10 2 110ft 61135 Hz 99.7 uH 61310 Hz 99.1 uH .570 % 568 QUADRUPOLE 2.0 x 10 2 120ft 60001 Hz 103.5 uH 60140 Hz 103.0 uH .462 % 478 QUADRUPOLE 3.2 x 10 2 120ft 59149 Hz 106.5 uH 59357 Hz 105.7 uH .700 X 745 QUADRUPOLE 2.4 x 10 2 150ft 55673 Hz 120.2 uH 55822 Hz 119.5 uH .533 % 641 QUADRUPOLE 3.3 x 10 2 150ft 54869 Hz 123.7 uH 55062 Hz 122.9 uH .700 X 866 QUADRUPOLE 3.3 x 10 2 165ft 54754 Hz 124.2 uH 54940 Hz 123.4 uH .676 % 840 QUADRUPOLE 2.0 x 10 2 175ft 55531 Hz 120.8 uH 55657 Hz 120.3 uH .452 % 546 QUADRUPOLE 4.0 x 10 2 175ft 55379 Hz 121.5 uH 55600 Hz 120.5 uH .793 X 964 QUADRUPOLE 2.2 x 10 2 180ft 55315 Hz 121.7 uH 55446 Hz 121.2 uH .472 X 575 QUADRUPOLE 2.3 x 10 2 180ft 56550 Hz 116.5 uH 56711 Hz 115.8 uH .567 % 660 QUADRUPOLE 2.1 x 10 2 200ft 52912 Hz 133.1 uH 53038 Hz 132.4 uH .475 % 631 QUADRUPOLE 2.3 x 10 2 200ft 53691 Hz 129.2 uH 53818 Hz 128.6 uH .471 % 609 QUADRUPOLE 2.5 x 10 2 200ft 56280 Hz 117.6 uH 56452 Hz 116.9 uH .608 % 716 QUADRUPOLE 3.0 x 10 2 200ft 53460 Hz 130.3 uH 53621 Hz 129.6 uH .600 % 782 QUADRUPOLE 3.3 x 10 2 200ft 53061 Hz 132.3 uH 53226 Hz 131.5 uH .619 % 819 QUADRUPOLE 2.0 x 10 2 205ft 50491 Hz 146.1 uH 50588 Hz 145.6 uH .383 % 560 QUADRUPOLE 3.3 x 10 2 205ft 52863 Hz 133.3 uH 52987 Hz 132.7 uH .467 % 623 QUADRUPOLE 3.9 x 10 2 210ft 51551 Hz 140.2 uH 51743 Hz 139.1 uH .741 % 1038 QUADRUPOLE 2.4 x 10 2 220ft 52448 Hz 135.4 uH 52582 Hz 134.7 uH .509 % 689 QUADRUPOLE 2.5 x 10 2 220ft 50615 Hz 145.4 uH 50727 Hz 144.8 uH .441 % 641 QUADRUPOLE 3.2 x 10 2 220ft 51646 Hz 139.7 uH 51806 Hz 138.8 uH .617 % 861 QUADRUPOLE 3.0 x 10 2 230ft 51468 Hz 140.6 uH 51629 Hz 139.7 uH .623 % 876 QUADRUPOLE 2.0 x 10 2 275ft 52164 Hz 136.9 uH 52300 Hz 136.2 uH .519 X 711 QUADRUPOLE 3.2 x 10 2 300ft 44920 Hz 184.6 uH 45027 Hz 183.7 uH .475 % 876 QUADRUPOLE 3.5 x 10 2 300ft 44543 Hz 187.7 uH 44640 Hz 186.9 uH .434 % 815 QUADRUPOLE 3.6 x 10 2 300ft 47152 Hz 167.5 uH 47272 Hz 166.7 uH .507 % 850 QUADRUPOLE 4.0 x 10 2 320ft 46193 Hz 174.6 uH 46329 Hz 173.5 uH .586 % 1023 QUADRUPOLE 4.0 x 10 2 335ft 46713 Hz 170.7 uH 46783 Hz 170.2 uH .299 % 510 QUADRUPOLE 3.2 x 10 2 350ft 47439 Hz 165.5 uH 47565 Hz 164.6 uH .529 % 876 QUADRUPOLE 4.0 x 10 2 600ft 46846 Hz 169.7 uH 46950 Hz 169.0 uH .443 % 751 18 EXHIBIT 8 1 1 1 1 1 1 1 1 1 1 1 1 1 MEASURED FREQUENCIES AND INDUCTANCE ON VARIOUS BICYCLE DETECTORS IN THE CITY OF CUPERTINO BICYCLE ON EDGE WIRES OF QUADRUPOLE DETECTOR + + INDUCTANCE INDUCTANCE LOOP SIZE NUMBER LEAD-IN MEASURED MEASURED MEASURED MEASURED SHIFT IN % SHIFT TOTAL LOOP TYP IN FEET OF TURNS LENGTH FREQUENCY INDUCTANCE FREQUENCY INDUCTANCE OF TOTAL NANOHENRIES + + + + + + + + + + + QUADRUPOLE 2.0 x 10 2 25ft 61114 Hz 99.7 uH 61123 Hz 99.7 uH .029 % 29 QUADRUPOLE 2.8 x 10 2 25ft 61573 Hz 98.3 uH 61613 Hz 98.1 uH .130 % 128 QUADRUPOLE 2.9 x 10 2 25ft 65806 Hz 86.0 uH 65850 Hz 85.9 uH .134 % 115 QUADRUPOLE 2.4 x 10 2 80ft 56333 Hz 117.4 uH 56359 Hz 117.3 uH .092 % 108 QUADRUPOLE 3.6 x 10 2 80ft 58400 Hz 109.2 uH 58446 Hz 109.0 uH .157 % 172 QUADRUPOLE 2.3 x 10 2 100ft 61647 Hz 98.0 uH 61680 Hz 97.9 uH .107 % 105 QUADRUPOLE 2.0 x 10 2 110ft 61135 Hz 99.7 uH 61156 Hz 99.6 uH .069 % 68 QUADRUPOLE 2.0 x 10 2 120ft 60001 Hz 103.5 uH 60025 Hz 103.4 uH .080 % 83 QUADRUPOLE 3.2 x 10 2 120ft 59149 Hz 106.5 uH 59192 Hz 106.3 uH .145 % 155 QUADRUPOLE 2.4 x 10 2 150ft 55673 Hz 120.2 uH 55701 Hz 120.1 uH .101 % 121 QUADRUPOLE 3.3 x 10 2 150ft 54869 Hz 123.7 uH 54897 Hz 123.6 uH .102 % 126 QUADRUPOLE 3.3 x 10 2 165ft 54754 Hz 124.2 uH 54794 Hz 124.1 uH .146 % 181 QUADRUPOLE 2.0 x 10 2 175ft 55531 Hz 120.8 uH 55548 Hz 120.7 uH .061 % 74 QUADRUPOLE 4.0 x 10 2 175ft 55379 Hz 121.5 uH 55422 Hz 121.3 uH .155 % 188 QUADRUPOLE 2.2 x 10 2 180ft 55315 Hz 121.7 uH 55336 Hz 121.6 uH .076 X 92 QUADRUPOLE 2.3 x 10 2 180ft 56550 Hz 116.5 uH 56573 Hz 116.4 uH .081 X 95 QUADRUPOLE 2.1 x 10 2 200ft 52912 Hz 133.1 uH 52932 Hz 133.0 uH .076 % 101 QUADRUPOLE 2.3 x 10 2 200ft 53691 Hz 129.2 uH 53713 Hz 129.1 uH .082 % 106 QUADRUPOLE 2.5 x 10 2 200ft 56280 Hz 117.6 uH 56305 Hz 117.5 uH .089 % 104 QUADRUPOLE 3.0 x 10 2 200ft 53460 Hz 130.3 uH 53486 Hz 130.2 uH .097 % 127 QUADRUPOLE 3.3 x 10 2 200ft 53061 Hz 132.3 uH 53086 Hz 132.2 uH .094 % 125 QUADRUPOLE 2.0 x 10 2 205ft 50491 Hz 146.1 uH 50505 Hz 146.0 uH .055 % 81 QUADRUPOLE 3.3 x 10 2 205ft 52863 Hz 133.3 uH 52897 Hz 133.1 uH .129 X 171 QUADRUPOLE 3.9 x 10 2 210ft 51551 Hz 140.2 uH 51584 Hz 140.0 uH .128 % 179 QUADRUPOLE 2.4 x 10 2 220ft 52448 Hz 135.4 uH 52466 Hz 135.3 uH .069 % 93 QUADRUPOLE 2.5 x 10 2 220ft 50615 Hz 145.4 uH 50638 Hz 145.3 uH .091 % 132 QUADRUPOLE 3.2 x 10 2 220ft 51646 Hz 139.7 uH 51674 Hz 139.5 uH .108 % 151 QUADRUPOLE 3.0 x 10 2 230ft 51468 Hz 140.6 uH 51492 Hz 140.5 uH .093 % 131 QUADRUPOLE 2.0 x 10 2 275ft 52164 Hz 136.9 uH 52178 Hz 136.8 uH .054 % 73 QUADRUPOLE 3.2 x 10 2 300ft 44920 Hz 184.6 uH 44943 Hz 184.4 uH .102 % 189 QUADRUPOLE 3.5 x 10 2 300ft 44543 Hz 187.7 uH 44552 Hz 187.7 uH .040 % 76 QUADRUPOLE 3.6 x 10 2 300ft 47152 Hz 167.5 uH 47178 Hz 167.4 uH .110 % 185 QUADRUPOLE 4.0 x 10 2 320ft 46193 Hz 174.6 uH 46221 Hz 174.4 uH .121 % 211 QUADRUPOLE 4.0 x 10 2 335ft 46713 Hz 170.7 uH 46724 Hz 170.6 uH .047 % 80 QUADRUPOLE 3.2 x 10 2 350ft 47439 Hz 165.5 uH 47462 Hz 165.4 uH .097 % 160 QUADRUPOLE 4.0 x 10 2 600ft 46846 Hz 169.7 uH 46908 Hz 169.3 uH .264 % 448 19 1 • 1 1 1 • 1 1 1 1 1 1 1 1 1 LOCATION: DIRECTION: SIZE: - MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEX: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: LOCATION: DIRECTION: SIZE: MEGAOHM: OHM(RESISTANCE): MEGAHERTZ -WITHOUT VEH: MEGAHERTZ -CENTER: MEGAHERTZ -SIDE: EXHIBIT 9 BICYCLE DETECTION PROJECT 1983 82-25 + + BUBB & SC. EB 24"x10' 100 1.5 52164 52300 52178 BUBB & SC WB 33"x10' 100 + 0.8 61573 61783 61613 85 OFF & SC EB 48"x10' 100 + 2.0 46193 46329 46221 85 OFF & SC WB 48"x10' 100 + 1.7 36713 36783 36724 85 ON &SC WB 48"x10' 100 + 2.5 46846 46950 46908 MARY & SC EB 38"x10' 100 + 1.8 47439 47565 47462 MARY & SC WB 43"x10' 100 0.8 58400 58621 58446 STELLING & SC NB 29"x10' 100 + 1.1 56333 56494 56359 DE ANZA & SC WB 42"x10' 100 + 2.0 44543 44640 44552 BLANEY SB 24"x10' 100 + 1.6 50491 50588 50505 WOLFE & SC EB 36"x10' 100 1.7 51468 51629 51492 N OF SC WOLFE & SC WB 40"x10' 100 1.3 53061 53226 53086 BLANEY as SC SB 40"x10' 100 + 1.2 52863 52987 52897 BLANEY S OF NB 24"x10' 100 + 0.7 61114 61262 61123 BLANEY 8 SC NB 35"x10' 100 + 0.5 65806 66096 65850 BLANEY & SC EB • 48"x10' 100 + 1.1 55379 55600 55422 BLANEY & SC WB 47"x10' 100 + 1.2 51551 51743 51584 PORTAL & SC EB 40"x10' 18.0 1.2 54754 54940 54794 20 FINCH & SC EB 38"x10' 100 + 1.8 44920 45027 44943 SC FINCH & SC WB 38"x10' 100 + 1.2 51646 51806 51674 MC & BUBB NB 29"x10' 100 + 1.8 55673 55822 55701 MC & BUBB SB 30"x10' 100 + 1.1 56280 56452 56305 MC & BUBB EB 25"x10' 100 + 1.4 52912 53038 52932 MC & BUBB WB 24"x10' 100 + 0.8 61135 61310 61156 CUPERTINO: MARCH 6, 1984 STELLING & SC SB 29"x10' 100 1.25 52448 52582 52466 STELLING & SC EB 38"x10' 100 + 0.8 59149 59357 59192 STELLING & SC WB 43"x10' 100 + 1.6 47152 47272 47178 MC & STELLING WB 24"x10' 100 + 1.0 55531 55657 55548 PORTAL & SC WB 39"x10' 100 + 1.2 54869 55062 54897 PERIMETER & SC EB 26"x10' 100 + 1.1 55315 55446 55336 PERIMETER & SC WB 36"x10' 100 + 1.2 53460 53621 53486 PEPPER & STELL NB 27"x10' 100 + 1.1 56550 56711 56573 MC & STELLING NB 30"x10' 100 + 1.6 50615 50727 50638 MC & STELLING SB 28"x10' 100 + 0.7 . 61647 61877 61680 MC & STELLING EB 24"x10' 100 + 1.0 60001 60140 60025 PEPPER & STELL SB 28"x10' 100 1.2 53691 53818 53713 EXHIBIT 10 + + 1 1 1 1 1 1 1 1 1 1 1 1 1 SENSITIVITY LEVELS THAT ACHIEVED BICYCLE DETECTION ON VARIOUS TYPES OF INDUCTIVE LOOP DETECTORS MINIMUM MINIMUM CALCULATED CALCULATED ABSOLUTE PERCENT LOOP SIZE NUMBER LOOP LEAD-IN LEAD-IN TOTAL SENSITIVITY CHANGE CHANGE LOOP TYPE LOCATION IN FEET OF TURNS INDUCTANCE LENGTH INDUCTANCE INDUCTANCE LEVEL REQUIRED REQUIRED + + + + + + + + + + + + STATE TYPE I ON CENTER 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH 7 8 nH .011 X STATE TYPE I ON EDGE 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH 2 256 nH 337 % STATE TYPE 1 1ft OUTSIDE 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH 5 32 nH .042 % STATE TYPE I ON CENTER 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH HIGH = 6 16 nH .021 % STATE TYPE I ON EDGE 6.0 x 6 3 64.9 uN 50ft 11.0 uH 75.9 uH LOW = 1 512 nH .674 % STATE TYPE I 1ft OUTSIDE 6.0 x 6 3 64.9 uN 50ft 11.0 uH 75.9 uH HIGH = 6 16 nH .021 % STATE TYPE I ON CENTER 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH NO DETECTION 0 nH .000 X STATE TYPE I ON EDGE 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH LOW = 1 512 nH .674 % STATE TYPE I 1ft OUTSIDE 6.0 x 6 3 64.9 uH 50ft 11.0 uN 75.9 uH HIGH = 6 16 nH .021 % STATE TYPE I ON CENTER 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH NO DETECTION 0 nH .000 % STATE TYPE I ON EDGE 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH LOW = 1 512 nH .674 % STATE TYPE I 1ft OUTSIDE 6.0 x 6 3 64.9 uH 50ft 11.0 uH 75.9 uH HIGH = 6 16 nH .021 % STATE TYPE II ON CENTER 6.0 x 6 3 129.8 uH 290ft 63.8 uH 193.6 uH 7 8 nH .004 % STATE TYPE II ON EDGE 6.0 x 6 3 129.8 uH 290ft 63.8 uH 193.6 uH 2 256 nN .132 % STATE TYPE I1 1ft OUTSIDE 6.0 x 6 3 129.8 uH 290ft 63.8 uH 193.6 uH 5 32 nH .017 % STATE TYPE II ON CENTER 6.0 x 6 3 129.8 uH 295ft 64.9'uH 194.7 uH 7 8 nH .004 % STATE TYPE II ON EDGE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH 2 256 nH .131 % STATE TYPE I! 1ft OUTSIDE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH 6 16 nH .008 X STATE TYPE II ON CENTER 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH NO DETECTION 0 nH .000 % STATE TYPE lI ON EDGE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH LOW = 1 512 nH .263 % STATE TYPE 11 1ft OUTSIDE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH NO DETECTION 0 nH .000 % STATE TYPE II ON CENTER 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH HIGH = 6 16 nH .008 % STATE TYPE Il ON EDGE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH MED = 3 128 nH .066 % STATE TYPE II 1ft OUTS1D(: 6.0 x 6 3 129.8 uH 295ft 64.9 uN 194.7 uH HIGH = 6 16 nH .008 % STATE TYPE II ON CENTER 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH NO DETECTION 0 nH .000 % STATE TYPE 11 ON EDGE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH LOW = 1 512 nH .263 % STATE TYPE II 1ft OUTSIDE 6.0 x 6 3 129.8 uH 295ft 64.9 uH 194.7 uH HIGH = 6 16 nH .008 X STATE TYPE III ON CENTER 6.0 x 6 3 194.8 uH 440ft 96.8 uH 291.6 uH NO DETECTION 0 nH .000 % STATE TYPE III ON EDGE 6.0 x 6 3 194.8 uH 440ft 96.8 uH 291.6 uH 5 32 nH .011 % STATE TYPE III 1ft OUTSIDE 6.0 x 6 3 194.8 uH 440ft 96.8 uH 291.6 uH NO DETECTION 0 nH .000 X STATE TYPE IV ON CENTER 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION 0 nH .000 % STATE TYPE IV ON EDGE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH 4 64 nH .023 % STATE TYPE IV 1ft OUTSIDE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH 7 8 nH .003 % STATE TYPE IV ON CENTER 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION 0 nH .000 % STATE TYPE IV ON EDGE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH MED = 3 128 nH .047 X STATE TYPE IV 1ft OUTSIDE 6.0 x 6 3 259.7 uH .60ft 13.2 uH 272.9 uH NO DETECTION nH .000 % STATE TYPE IV ON CENTER 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION nH .000 % STATE TYPE IV ON EDGE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH MED = 3 12 nH .047 % STATE TYPE IV 1ft OUTSIDE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION nH .000 % STATE TYPE IV ON CENTER 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION nH .000 % STATE TYPE IV ON EDGE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH MED = 3 12 nH .047 % STATE TYPE IV 1ft OUTSIDE 6.0 x 6 3 259.7 uH 60ft 13.2 uH 272.9 uH NO DETECTION nN .000 % QUADRUPOLE ON CENTER 5.0 x 16 2 139.5 uH 75ft 16.5 uH 156.0 uH 2 25 nH .164 % QUADRUPOLE ON EDGE 5.0 x 16 2 139.5 uH 75ft 16.5 uH 156.0 uH 4 64 nH .041 % QUADRUPOLE 1ft OUTSIDE 5.0 x 16 2 139.5 uH 75ft 16.5 uH 156.0 uH 7 nH .005 % QUADRUPOLE ON CENTER 5.0 x 16 2 139.5 uH 100ft 22.0 uH 161.5 uH 2 25 nH .159 X QUADRUPOLE ON EDGE 5.0 x 16 2 139.5 uH 100ft 22.0 uH 161.5 uN 4 64 nH .040 % QUADRUPOLE 1ft OUTSIDE 5.0 x 16 2 139.5 uH 100ft 22.0 uH 161.5 uH 7 nH .005 % QUADRUPOLE ON CENTER 6.0 x 6 2 62.5 uH 160ft 35.2 uH 97.7 uH 2 25 nH .262 % QUADRUPOLE ON EDGE 6.0 x 6 2 64.3 uH 160ft 35.2 uH 99.5 uH 4 64 nH .064 % QUADRUPOLE 1ft OUTSIDE 6.0 x 6 2 64.3 uH 160ft 35.2 uH 99.5 uH 7 nH .008 % QUADRUPOLE ON CENTER 6.0 x 16 2 144.3 uH 50ft 11.0 uH 155.3 uH 1 51 nH .330 % QUADRUPOLE ON EDGE 6.0 x 16 2 144.3 uH 50ft 11.0 uH 155.3 uH 3 12 nH .082 % QUADRUPOLE 1ft OUTSIDE 6.0 x 16 2 144.3 uH 50ft 11.0 uH 155.3 uH 7 nH .005 % NOTE: ANY LINES WITH DUPLICATED DATA ARE THE RESULT OF DIFFERENT BRAND DETECTORS. 21 1 1 1 1 1 1 1 1 1 1 1 1 1 With a little experimentation, you will discover that inductance for square and rectangular loops can be calculated by multiplying the perimeter in feet by those same constants. Why engineers derive fancy formulas when simple ones work is beyond the scope of this project but worth mentioning. Lead-in Cable Although the lead-in cable is only the connector between the loop and the amplifier, it is an important element in the system in that it adds inductance to the system. The longer the lead-in the more the inductance. It is important to remember that it is the combination of loop inductance and lead-in inductance that must fall within the limitation range of the detector amplifier. In addition, the inductance value of the loop should be at least double that of the inductance of the lead-in .cable in order to ensure reliable performance of the total detector system. The inductance of the lead-in cable will be approxi- mately 0.23 Microhenries per foot. By measuring inductance at the traffic signal cabinet and knowing the length of the lead-in cable you can determine the approximate induc- tance value of the loop itself. If the values are suspect, you can isolate each component by measuring at the pull box next to the loop. As an example, a 6 foot by 6 foot square loop with an inductance of around 36 Microhenries must be a two (2) turn loop. A lead-in cable length in excess of 80 feet would violate the rule that the loop inductance should be twice that of the cable (80*0.23=18.4)> (36/2=18.0). If this loop were replaced with one with three (3) turns, then a cable length of 150 feet could be supported (150*0.23=34.5)<(72/2=36). Detector Amplifier The detector amplifier is the easiest and cheapest element in the detector system to replace. This is primarily due to the labor costs involved with the replacement of the loop itself or the lead-in cable. It is also the most important element in the system. There are two (2) basic logic circuits in general use: analog and digital. If bicycles are to be reliably detected, all detector amplifier units with analog circuitry should be replaced with digital circuit units. This is recommended as the analog amplifiers are reported to be unstable and cannot be relied upon to consistently detect bicycles at higher sensitivity levels. Replacement can occur as these amplifiers need repairs, when a specific problem is reported or as a result of the City's ongoing controller replacement program. 22 1 r i 1 1 1 1 1 1 1 1 1 1 1 Digital detector amplifier units sense changes in inductance in two (2) ways: absolute change and percent change. When a metal mass crosses into the loop area, a change of inductance occurs. The amplifier that detects absolute changes in inductance does so regardless of the total inductance of the detector system. The amplifier that detects percent change does so by dividing the value of the inductance change by the value of the total induc- tance, which establishes the percent change to be compared to the threshold values of the detector amplifier. The sensitivity ranges that determine the threshold values come in two (2) types also: three (3) steps and eight (8) steps. Typical threshold values are as follows: TYPICAL DETECTION THRESHOLDS AND SENSITIVITY SETTINGS Sensitivity 1 2 3 4 5 6 7 8 Nanohenry 512nH 256nH 128nH 64nH 32nH 16nH 8nH 4nH Percent nH .257% .129% .086% .064% .032% .021% .016% .011% Sensitivity LOW MED HI Percent nH .32% .08% .02% The length of lead-in can become critical to the system that detects percent change as it increases the total inductance of the system. A typical bicycle will produce a change in inductance of approximately 16 nanohenries or less on a Caltrans Type A loop when ridden in the center of the loop. Sixteen (16) nanohenries divided by the total inductance of the system can produce a very small percent change. The bicycle used in the study by the City of Cupertino produced an inductance change of less than 16 nanohenries as only one (1) amplifier in four (4) detected that bicycle at the 16 nH threshold. The detector amplifier that reacts to absolute change will sense the 16 nanohenry change whereas the other will divide the 16 nanohenry change by the total inductance of the loop and lead-in combination and sense the percent change. The longer the lead-in, the smaller the percent change and therefore the task of detecting bicycles becomes more difficult with the latter type of amplifier. For this reason we are recommending the amplifier that measures absolute shift. A sample specification is provided in Exhibit 11. 23 1 1 1 1 1 1 1 1 1 1 1 1 1 •' 1 1 1 1 1 EXHIBIT 11 SPECIFICATION OF INDUCTIVE LOOP DETECTORS Loop detectors shall conform to Section 86-5 of the Standard Specifications of the State of California dated July 1984 and Section 11 of the NEMA Standards Publication No. TS 1-1983. Each detector unit may contain up to four (4) detector channels. Each channel shall automatically self tune to any loop and lead-in combination from twenty (20) to two thousand (2,000) microhenries. The detector unit shall scan each channel in sequence and only one (1) channel input per unit shall be active at any point in time. Sequential scanning shall prevent crosstalk between channels of a detector. The detector shall use absolute shift in inductance of the loop and lead-in combination as the means to com- pare actual inductance shift to threshold values to achieve an actuation. The detector shall cause an actua- tion to occur when an absolute shift in inductance of four (4) or more nanohenries is measured. The detector shall have eight (8) separate sensi- tivity settings with threshold values of 4, 8, 16, 32, 64, 128, 256 and 512 nanohenries, respectively. 24 1 1 r 1 1 1 1 1 1 1 1 1 1 1 1 1 1 COMBINATION BICYCLE/VEHICLE DETECTOR SYSTEMS The combination bicycle/vehicle detector system, in one case, is one where a vehicle detector that was designed to accommodate motor vehicles is compromised at the amplifier through tuning to also detect bicycles. The price to be paid for this compromise is often adjacent lane detection. The sensitivity of the detector amplifier is tuned to the higher levels and the area in which motor vehicles can be detected spills into the adjacent lane. If the lane is for vehicles traveling in the same direction, then the consequences are fairly minimal. However, when the lane is a left turn only lane or a lane for traffic in the opposite direction, the traffic signal phases can be extended by traffic actually leaving the intersection or a phase can be served when no traffic on the approach is present. This causes the intersection to operate ineffic- iently and creates calls to the maintenance people for malfunctions that are difficult to analyze and impossible to cure. Some correction to this problem can be made by narrowing the width of the loop. However, care must be exercised. As the loop gets narrower in the lane, the probability that bicycles and even motorcycles could bypass the loop and not be detected increases. In the other case, the detector system is specifically designed to accommodate bicycles where all other traffic must be detected. Typically these systems will detect the other traffic on the roadway even though the area of detection above the pavement is lower. In the case of quadrupole detectors in particular the sensitivity on the center is high enough to detect some portion of any vehicle. High bed trucks will be detected at the axles and differential cases by these types of detector configura- tions. This can be a disadvantage if the purpose of the detection is to count or classify the vehicles. However, there is no particular problem created if the purpose is to activate a traffic signal. In fact, there is an argu- able advantage if the volume density features of a con- troller are being used. When each axle of a truck is detected while approaching a red light, the added initial will create more time for the next green displayed. This allows more initial start up time for the slower accelera- tion rates of trucks. 25 1 1 3 1 3 1 a 3 1 1 1 3 1 1 1 1 BICYCLE DETECTOR LOCATION ANALYSIS Detectors for bicycles must be placed in a position on the roadway where bicyclists can be expected to ride. On streets with bike lanes this is really an easy task. The bike lane area can be covered adequately by a quadrupole detector that will sense the presence of any bicycle as long as it is ridden in the lane. The adjacent traffic lane will not respond to this detector as a result of the cut-off characteristics of the quadrupole loop. Detectors in left turn only lanes and on approaches to intersections without bike lanes must be designed to accommodate both the bicycle and motor vehicles of all sizes while avoiding adjacent lane detection. This also is easy to accomplish if the bicyclist rides on the detector over the most sensitive area,, directly over the loop wires. Placement of bicycle detectors in advance of an intersection is done in at least two (2) ways. The detec- tor is placed in advance of the intersection in the same manner as the vehicle detector is placed. That is, the distance from the stop line is determined by 1) approach speed, 2) reaction time and 3) stopping distance (see Exhibit 12). This is the method used by Caltrans, the City of Cupertino and the County of Santa Barbara and is illus- trated in the Caltrans design manual. The distance of + 50 feet is based on an average approach speed for bicycles of 16 mph. This method is particularly useful on arterial approaches where the phase is usually recalled and vehicles approaching will usually be seeing a green signal. If the general speeds of bicyclists vary from the average speeds used to determine the placement of the detector in the Caltrans manual, then the appropriate distance can be calculated for each approach of an inter- section. Upgrade and downgrade approaches will have sig- nificantly different approach speeds than from level approaches. These are examples where the designer or engi- neer should alter the distance to accommodate slower or faster approach speeds. The age and physical condition of the majority of bicyclists using the facility can also alter these parameters. A similar system in use in the City of Cupertino utilizes a detector placed in advance of the stop line, much like the above example, and another detector placed at the stop line. When the bicycle is detected on the first loop, extension time is provided to hold the signal green until it reaches the second, or loop closest to the stop line. When the detection is made at the second loop, extension time is again provided to be sure that the bicyclist is far enough into the intersection to safely clear before the end of the clearance interval (yellow plus any all -red indication). The particular detector 26 8.0 12.0 12.0 14.0 16.0 18.0 20.0 22.0 24.0 26.0 28.0 30.0 35.0 40.0 45.0 1 55.0 55.0 1 1 1 EXHIBIT 12 + + SUGGESTED DETECTOR DISTANCES FROM STOP LINE CALTRANS FORMULAS FOR MOTOR VEHICLE TRAFFIC SPEED SPEED DEC. TIME DEC. DIST TOTAL TIME TOTAL DIST DIST MPH Ft/Sec SECONDS FEET SECONDS FEET TO USE + + + + + 11.7 .98 5.7 1.98 17.5 20 14.7 1.22 9.0 2.22 23.6 25 17.6 1.47 12.9 2.47 '30.5 30 20.5 1.71 17.6 2.71 38.1 40 23.5 1.96 22.9 2.96 46.4 45 26.4 2.20 29.0 3.20 55.4 55 29.3 2.44 35.9 3.44 65.2 65 32.3 2.69 43.4 3.69 75.6 75 35.2 2.93 51.6 3.93 86.8 85 38.1 3.18 60.6 4.18 98.7 95 41.1 3.42 70.3 4.42 111.3 110 44.0 3.67 80.7 4.67 124.7 125 51.3 4.28 109.8 5.28 161.1 160 58.7 4.89 143.4 5.89 202.1 200 66.0 5.50 181.5 6.50 247.5 250 73.3 6.11 224.1 7.11 297.4 300 80.7 6.72 271.1 7.72 351.8 350 + + + + + + DESIGN STOPPING SIGHT DISTANCES FOR BICYCLES DESIGN SPEED FEET @ 0% FEET @ 5% FEET @ 10% FEET @ 15% + + + + + + 10 MPH 50 50 60 70 + + + + + + 15 MPH 85 90 100 130 + + + + + + 20 MPH 130 140 160 200 + + + + + + 25 MPH 175 200 230 300 + + + + + + 30 MPH 230 260 310 400 + + + + + + + + + + + + 1 27 1 1 1 1 1 1 1 1 1 1 t 1 1 1 1 amplifier in use in Cupertino also has a minimum timing feature that is used when a bicycle is on the detector while the signal is red. A discrete minimum time is pro- vided that is greater than the vehicle minimum time and less than a pedestrian interval. Unfortunately, this unit is no longer manufactured; however, there are amplifiers on the market with extension and delay features that will function for most features of this design. Detectors on minor approaches to the intersection should be placed at the stop line in a position where bicyclists are known to ride. In general, this will be near the right hand edge of the roadway, except on one-way streets. Where bicyclists desire to cross the major street there should be space enough between the detector and curb so that right turns by vehicles can be made on the right side of the bicyclist. This configuration is a prime candidate for detector location marking. The detector will be some distance from the curb and to the right of the vehicle through lane. The right edge of the vehicle lane most likely will not be marked and the bicycle detector will be difficult to locate. If adequate space is not available and it is found that right turning vehicles activate the signal, then delayed call features of a detector amplifier can be used to maintain the efficiency of the- signal system by eliminating or reducing false detections from the side street. Bicyclists turning left should be in the lane nearest the center of the roadway, be it a left turn only lane or not. Therefore, it is important that the detector(s) being used for vehicles is/are also sensitive enough to detect bicycles. 28 1 1 1 1 7 1 1 1 1 a a 1 1 1 1 1 1 INVESTIGATION OF DETECTION DEVICES ON BICYCES A search has been made to determine if there is a device that could be installed on a bicycle to make it more detectable by existing detector systems. There has been talk of such a device and even ail article written about how such a device would operate.- One manufacturer has contacted us to inquire of our knowledge of such a device and its principles as they were interested in marketing new items in the bicycle equipment field. How- ever, we have been unable to find any new technology that could be applied to this problem. It would seem that what is needed is a device to emulate the metal that creates the eddy currents created by vehicles. There is a device available that is used to activate traffic signal loops to favor certain types of vehicles. It was designed for emergency vehicles, and is attached to them, so that intersections could be activated to favor their approach. This might be adaptable to the bicycle but would require a separate receiver in each traffic signal cabinet. The receiver costs approximately $400.00 and the unit mounted on the bicycle costs from $96.00 to $125.00. The transmitter, mounted on the bicycle, requires 12 volts DC to operate it. It is highly unlikely that every bicy- clist can be convinced to expend the money required or be willing to carry the extra weight to be assured that the detectors in San Diego will respond to his/her bicycle. The cost to the City to install one (1) receiver in each cabinet that has an actuated traffic signal controller exceeds $300,000.00. At certain intersections there will be a need to install one (1) receiver for each phase. This approach is clearly not viable from an economic or func- tional point of view, as this same device would not work in another city and bicyclists visiting San Diego would be unable to activate the traffic signals without one. Installing flat aluminum pieces in the frame members and/or discs on the wheels would probably improve the capability of the bicycle to create the eddy currents required to achieve detection. We have not experimented with this approach but the theory seems consistent with the way loop detectors work. Research and development in unknown areas can be extensive and time consuming and could produce no positive results. This kind of work is clearly beyond the scope of this project. 29 1 1 1 1 1 1 1 1 1 1 1 r 1 • 1 INTERIM BICYCLE DETECTION IMPROVEMENTS Interim measures are those things that can be done immediately and at a relatively small cost (see Exhibit 13) to improve the usability of traffic signals by bicy- clists. The intersections should be prioritized and those serving the most bicyclists should be reviewed first. Traffic signals adjacent to all schools and other identi- fied bicycle traffic generators will be high on the prior- ity list. The order of work should be as follows: o Adjust the existing detector amplifier to a higher sensitivity level. If this fails or causes other problems such as adjacent lane detection; o Adjust the minimum time on the phase and/or place that phase on recall. This is temporary until you can; o Check the terminal blocks for loose screws. o Check the loop splices for connections or corrosion. o "Test the loop and lead-in combination for: a. Initial loop frequency b. Stability of frequency c. Accuracy of frequency change o "Meggar" the detector to check resistance to ground (100 megohms minimum). o Install a new detector amplifier on the existing loop system. If this fails; o Mark the loop on the edge of a square detector and in the center of a quadrupole detector with a symbol that represents a bicycle. o Install pedestrian push buttons, with bicycle signs, facing the traffic side of the signal pole. 30 1 a 1 EXHIBIT 13 COSTS OF INTERIM MEASURES Costs for implementing the interim measures the text are based on actual invoice costs, possible. Estimates have been made for the existing maintenance personnel to perform adjus testing based on our experience as to the time including travel times. Adjust existing detector sensitivity 11 Adjust minimum time or set recall Check terminal blocks and screws Check loop and lead-in splices Test loop and lead-in combination "Megger" loop detector to ground Install new detector amplifier Mark detector with bicycle symbol Install pedestrian push buttons 1 1 3 1 1 3 1 1 1 3 1 1 31 listed in wherever costs of tments and required $ 0 - $ 0 - $ 0 $ 25 $ 25 $ 25 $100 $ 25 $ 70 IMP 25.00 25.00 25.00 100.00 100.00 100.00 200.00 35.00 120.00 1 1 1 1 1 1 1 1 1 1 1 1 1 1 POLICY DETERMINATION AND RECOMMENDATIONS The California Vehicle Code grants to the bicyclist all of the rights and privileges of a motor vehicle to operate upon the roadway. The bicyclist is subject to all of the duties and responsibilities of a motor vehicle in exchange for the rights and privileges. When a motor vehicle approaches a traffic signal, the driver has a reasonable expectation that within a certain amount of time the traffic signal will respond and the right-of-way will be transferred to that approach. The bicylist, having been granted the rights of a motor vihicle, has the same expectations, which are also reasonable. The technical means by which these expectations are met need not be identical to those applied to motorists; however, they should be recognized and satisfied as a matter of policy. The policy of the City of San Diego should be to make all traffic signals usable by bicyclists through the use of traffic detector systems or other devices that will detect the presence or passage of bicycles of the lightest variety. This policy should be implemented at the earliest possible date while having due regard for fiscal con- straints. Interim measures, listed above, should be implemented on existing traffic signal systems immediately and main- tained until such time as other required improvements can be made. All new traffic signal system designs should specifi- cally address the need to service bicycle traffic and the means by which this is to be accomplished. Vehicle detec- tors should be designed so that they are sensitive enough to detect all traffic, including bicycles, and detectors for the exclusive use of bicycles should be installed in bike lane approaches to the intersections. The incremental cost of adding these features is so small as compared to the overall project costs that their addition should be a design feature that satisfies the City's policy. The City's traffic signal controller replacement program should continue or be accelerated in order to provide the most efficient and reliable equipment avail- able for use in detecting bicycle traffic. Type D (modified quadrupole) and Type Q (quadrupole) detector loops should be the standard configurations to be used alone or in combination with Type A loops. Left turn lanes and minor side street applications should use State Type 5DA loop installations. Through traffic lanes that are shared by motor vehicles and bicycles should use Type D (modified quadrupole) loops. Detectors at the stop line that are used for presence or calling purposes are 32 1 1 1 1 1 1 1 1 1 r 1 L 1 1 considered to be shared use detectors. Type D loops used alone or in combination with one (1), two (2) or three (3) Type A loops should have five (5) turns of conductors. The Type 5DA loop installation has five (5) turns of conductors in the Type D loop. These combination loop detectors should be spliced in series with each other at the pull box. Advance detectors on arterials will not be expected to be shared by bicyclists; therefore, Type A loops are recommended. Bike lanes that require narrow areas of detection and sharp cut-off properties should have Type Q (quadrupole) loops. These loops should cover as much of the lane as possible. The edges of the loop should be installed one (1) foot to the right of the bike lane line and six (6) inches from the gutter lip. The width will vary but it is not critical to the operation. Pedestrian push buttons should only be used in locations where it is not possible to reliably detect the presence of bicycle traffic or as an interim measure to ensure safe passage of bicycles until adequate detection systems can be installed. Inductive loops should be marked at locations where the sensitivity is critical or where detection is not reliably achieved when the bicyclists ride in the approach lane in a position that is appropriate. Bicycle auxiliary timing devices should be considered in special cases such as crossing very wide arterials where long minimum times are detrimental to efficiency. They should be connected to the inductive loop detector amplifiers or to pedestrian style push buttons. The City should apply for and use TDA (Transportation Development Act) Article 3 funds to implement bicycle related facilities improvements that qualify. Other funds should also be obligated to facilities improvements; however, TDA funding should be used first to reduce the impacts of bicycle improvements on the General Funds or Gas Tax Funds. Detector sensitivity levels could be added to the traffic signal timing charts so that the regular mainten- ance personnel can maintain the required sensitivity levels as a routine procedure. Exhibit 14 illustrates how sensitivity levels might be incorporated in the City's standard timing chart. Inductive loop amplifiers that measure absolute change in inductance and feature eight (8) sensitivity levels should be specified for use in new signal installa- tions and should be used in a retrofit program. 33 1 TRAFFIC SIGNAL TIMING - BITS 152 PHASE TIMING 1 1 1 1 a 1 1 r 4, , t PM EM►T PHASE • .....r 1 2 3 4 E 9 7 9 E WALK 0 7 7 7 7 R RI DELAY 0 FLASH DPW 1 !IP /6 • /S /7 RRI CLEAR 1 MIN GREEN 2 .7.0 /O.O Jo .7•0 /O.6 .T•0 EV A DELAY G 2 TYPE 3OET 3 EV ACLEAR 3 3 ADDNEH 4 EV 9 DELAY • VEH EXTEN 9 2.0 448 .T.O ..o 4SB .40 EV 9 CLEAR 9 MAX GAP 9 2.0 9.9 A o 2.0 9.8 .7., EV C DELAY G 9 MIN GAP 7 .7.o ,0'.2 JO .T•o O.2 -7_a EVCCLEAR 3 7 MAX EXTEN 9 3a • c6.o ed.. • [ Pt,., EVDDELAY 3 MAX 2 9 3o. o Co. a 01.o _30•••0 3a-o 6oa yO,•,o EV ID CLEAR 9 A iC S Y s✓--f-_tea --lif RR]DELAY A 9 ,.r,; _ 1•0 1 .y RR7 CLEAR 9 REDUCE 9Y C G./ - p./ d+'.: C REDUCE EVERY 0 0.7 0.7 rDE'i"." 0 YELLOW E 3.o y S 9.0 3.0 y,S 3.6 ?yL :'_�L j :.. 1 E RED CLEAR F �.p AO 1 .O 14 _GL gay -tt• FAR OLY*TMH •• 1. rak, F 'SENSITIVITY 3 - 5 4 % • RROLYTMR,. `'�� MAX INITIAL 1F-0-E) • O RCTSTROKCS: I • • LOCATION PHASE FUNCTION FLAGS PHASE 1 2 3 A 6 • 7 • PERMIT 0 X X X X X X RIO LOCK 1 TELLOR LOCK 7 vim RECALL 3 it X PEG RECALL 4 /� ZEDS 6 I.'• - ;T y:•T' •j7 -7 REST IN MALA 6 RED REST 7 DOUBLE ErRv • Y TI 1 MAt RECALL • /- OVERLA. A A OVERLAP • 9 OVERLAP C C OVERLAP 0 O •TARTUr • X IRESERVEDI P ♦ • F • FUNCTION • 2>••04• 6r 71J'�Y�Iti RED REVERT (F-D-FI• J� PHASE SEOUENCES PR•SE 1 3 A S 6 7 • X LAG 0 IFREEI 0 X X LAG I 1 LAG 7 2 LAG 3 3 LAG A 4 LAGS 5 LAG 6 6 LAG 7 7 LAG• • LAG • 9 COOR MAX RECALL A COOR LAG RECALL • 61•NC►RASES C '' •\ '. L. iT. «'Z -r- '. • NEXT PRASE E • ' T•F..� Li' f'-.. ' .0' .. FORCE OFF F •i' n:•�yy L J. RCT•TRORES C • • • FUNCTION • 06.+10.14 a• .P •4>t dor A S•c a ,- li.y ,ali79 "eL ••TP •• •. Well PAGE 1OF.....2n. EXHIBIT 14 SAMPLE SIGNAL TIMING CHART WITH SENSITIVITY VALUES a 34 1 1 111 1 1 1 1 1 1 1 1 1 1 1 GLOSSARY OF TERMS ACTUATION: The output from any type of detector to the controller unit. ADDED INITIAL: Green time that is added to a phase by actuations of the vehicle detector during the red signal indication of that phase. ADLER'S HORN: Detector unit activated by the sound of an automobile horn near its sensor. The sensor was accompanied by a sign that read "Stop - Sound Horn to Clear Signal." AMPLIFIER, DETECTOR: A device that is capable of intensifying the electrical energy produced by a sensor. A loop detector unit is commonly called an amplifier even though its electronic function is actually different. ANALOG: An electronic design that uses continuously variable quantities such as voltages, rather than numbers. AREA DETECTION: The continuous detection of vehicles over a length of roadway wherein the call is intended to be held as long as there is a vehicle in the detection area. AUXILIARY EQUIPMENT: Separate devices used to add supplementary features to a controller assembly. CALL: A registration of a demand for right-of-way by traffic at a controller unit. The call comes to the controller from a detector unit that is outputting an actuation. CHANNEL: Electronic circuitry which functions as a loop detector unit. CONTINUOUS PRESENCE MODE: Detector output continues if a vehicle remains in the field of influence of the detector. CONTROLLER ASSEMBLY: A complete electrical mechanism mounted in a cabinet for controlling the operation of a traffic control signal. CONTROLLER UNIT: The part of the controller assembly which performs the basic timing and logic functions. 1 1 1 1 1 1 1 1 1 1 1 1 1 CYCLE: A complete sequence of signal indications for all approaches for which there is a demand or call by traffic. DELAYED CALL DETECTOR: A detector that does not issue an output until the detection zone has been occupied for a period of time that has been set on the detector unit. DELAYED OUTPUT: The ability of a detector to output for a predetermined length of time. DETECTOR: A device for indicating the presence of vehicles, bicycles or pedestrians. DETECTOR AMPLIFIER: See AMPLIFIER, DETECTOR. DETECTOR MODE: A term used to describe the duration and conditions of the occurrence of a detection output. a. Pulse Mode b. Presence Mode, DETECTOR SYSTEM: The complete sensing and indicating group consisting of the detector unit, transmission lines and sensor. DETECTOR SETBACK: Longitudinal distance between the stop line and the detector. DETECTOR UNIT: The portion of a detector system other than the sensor and lead-in, consisting of an electronics assembly. EDDY CURRENT: An electric current induced within the body of a conductor when it moves through a nonuniform magnetic field. EXTENDED CALL DETECTOR: A detector with carryover output. It holds the call of a vehicle for a period of time that has been set on the detector unit. EXTENSION TIME: Extra time resulting from detector actua- tions to allow safe passage of vehicles through an intersection. INDUCTANCE: That property of an electric circuit or of two (2) neighboring circuits whereby an electromotive force is generated in one circuit by a change of current in itself or in the other. The ratio of the electromotive force to the rate of change of the circuit. KHz: Kilohertz, or thousands of hertz. Hertz means "cycles per second", a measurement of frequency. delay its or passage 3 1 1 1 1 a 1 1 1 t 1 L 1 1 1 L: The change in inductance. LEAD-IN CABLE: The electrical cable which serves to connect the loop to the detector unit. LOOP DETECTOR: A detector that senses a change in inductance of its inductive loop sensor caused by the passage or presence of a vehicle near the sensor. MAGNETIC DETECTOR: A detector that senses changes in the earth's magnetic field caused by the movement of a vehicle near its sensor unit. MAGNETOMETER: A detector that measures the difference in the level of the earth's magnetic forces caused by the passage or presence of a vehicle near its sensor. MEGGER: A device used to measure very high resistance to earth ground. MEGOHM: One (1) million ohms, which is the unit of measure of electrical resistance. MICROHENRY: One (1) millionth of a henry, from the unit of measure of inductance. MINIMUM GREEN INTERVAL: The shortest green time allowed for an interval. The controller will not display a green interval less than the minimum time set. NANOHENRY: One (1) billionth of a henry, from the unit of measure of inductance. OHM: The unit of electrical resistance equal to the resistance through which a current of one (1) ampere will flow when there is a potential difference of one (1) volt across it. PEDESTRIAN DETECTOR: A detector, usually a push button, that is responsive to operation by or the presence of a pedestrian. PEDESTRIAN PHASE: A traffic phase allocated to pedestrian traffic either concurrently with a vehicle phase or exclusive of other phases. PHASE: A part of the cycle allocated to any traffic movements receiving the right-of-way. PHASE SEQUENCE: A predetermined order in which the phases of a cycle occur. 1 1 1 1 j 1 1 1 1 1 1 1 1 POINT DETECTION: The detection of vehicles as they pass a specific point on the roadway, also referred to as small area detection. PRESENCE LOOP DETECTOR: An induction loop detector which is capable of detecting the presence of standing or moving vehicles within the effective area. PROBE: The sensor form that is commonly used with a magnetometer type detector unit. PULSE MODE: Detector output is a short pulse of approximately 100ms even when the vehicle remains in the effective area for a longer period of time. QUADRUPOLE: A loop configuration that is essentially two (2) loops with a common side. The wires are wound continuously in a figure eight (8) pattern so that current flow in the common side is in the' same direction. The design improves sensitivity to small vehicles and reduces adjacent lane detection. RADAR DETECTOR: A vehicle detector activated by the passage of vehicles through its field of emitted microwave energy. RADIO FREQUENCY DETECTOR: A vehicle detector consisting of a loop of wire imbedded in the roadway that is tuned to receive a preselected radio frequency from a transmitter located on a vehicle. REJECTION (Adjacent Lane): The ability of a detector to not detect vehicles in an adjacent lane. SCANNING DETECTOR: A multichannel detector in which the loop(s) of each channel are energized in sequence, one at a time, in quick succession. SENSITIVITY: The setting on the detector unit that determines the amount of inductance shift required to actuate the detector. High sensitivities require low inductance shifts. SENSOR UNIT: An electrical conductor ("loop") in the roadway designed such that the presence or passage of a vehicle causes a decrease in the inductance of the loop. SONIC DETECTOR: A vehicle detector which emits high frequency sound energy and senses the reflection of that energy from a vehicle in its field. SOUND SENSITIVE DETECTOR: See Adier's horn. THRESHOLDING: A minimum level of change in inductance which occurs to produce an actuation. ULTRASONIC DETECTOR: A detector that senses the presence or passage of vehicles through its field of emitted ultrasonic energy. 1 a 1 3 1 1 1 1 1 1 4. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 BIBLIOGRAPHY 1. TRAFFIC DETECTORS HANDBOOK, tration Publication IP-83-2. 2. DIGITAL LOOP TESTING SYSTEM, Product Manual for Frequency Federal Highway Adminis- Detector Systems, Inc. Tester, April 9, 1985. 3. INDUCTIVE LOOP DETECTOR SPECIFICATIONS AND TESTS, County of Sacramento, May, 1977, Rev. October, 1978 and January, 1984. 4. SELF INDUCTANCE FORMULAS FOR QUADRUPOLE LOOPS USED WITH VEHICLE DETECTORS, Milton K. Mills, U.S. Depart- ment of Transportation, Federal Highway Administra- tion, March 21, 1985. 5. THE ADJUSTABLE LOOP FOR VEHICLE DETECTION, Wendell A. Blikken, Engineer, Michigan Department of Trans- portation, Detroit Freeways Operation Unit, 1979. 6. THE ART OF DETECTION - A SYSTEM CONCEPT, IMSA Journal, George E. Palm, 3M Company, March - April, 1982. 7. INDUCTIVE LOOP VEHICLE DETECTORS, IMSA Journal, Tom Potter, President, Detector Systems, Inc., March - April, 1982. 8. DETECTION SYSTEMS FOR THE SMALL VEHICLE BOOM, ITE District 6 Annual Meeting, Glenn M. Grigg, Traffic Engineer, City of Cupertino, July, 1980. 9. CUPERTINO'S BICYCLE FACILITIES, Bicycle Forum, Number 6, Glenn M. Grigg, Traffic Engineer, City of Cupertino. 10. CUPERTINO TESTS ITS LOOPS, Bicycle Forum, Number 10, Glenn M. Grigg, Traffic Engineer, City of Cupertino. 11. HOW TO (SORT OF) RIDE A BIKE, The Spinning Crank, Glenn M. Grigg, Traffic Engineer, City of Cupertino, September -October, 1980. 12. DETECTORS REVISITED (If You Can Find Them), The Spinning Crank, Glenn M. Grigg, Traffic Engineer, City of Cupertino, November -December, 1980. 13. TRAFFIC SIGNAL DETECTORS THE PSYCHOKINETIC CONNEC- TION, The Spinning Crank, Glenn M. Grigg, Traffic Engineer, City of Cupertino, May -June, 1981. 1 1 1 1 1 1 1 1 1 1 1 1 1 14. DETECTOR, DETECTOR, WHEREFORE ART THOU, LOUSY DETECTOR, The Spinning Crank, Glenn M. Grigg, Traffic Engineer, City of Cupertino, August -September, 1981. 15. PUSH BUTTONS, PUSH BUTTONS, THOSE DAMN LOUSY PUSH BUTTONS, The Spinning Crank, Glenn M. Grigg, Traffic Engineer, City of Cupertino, August -September, 1981. 16. DETECTING BICYCLES AT TRAFFIC SIGNALS, Technical Notes, Glenn M. Grigg, Traffic Engineer, City of Cupertino, July, 1981. 17. SMALL CYCLE DETECTION AT ACTUATED SIGNAL CONTROLLED INTERSECTIONS, Technical Notes, J. A. Butler and B. M. Snipes, Traffic Engineering Department, Clarke County, Georgia, December, 1980. 18. PLANNING AND DESIGN CRITERIA FOR BIKEWAYS IN CALIFORNIA, State of California, Department of Transportation, June 30, 1978. 19. CHARACTERISTICS OF THE REGULAR ADULT BICYCLE USER, U. S. Department of Transportation, Federal Highway Administration, Jerrold A. Kaplan, July, 1975. 20. A BIKEWAY CRITERIA DIGEST, U. S.- Department of Transportation, Federal Highway Administration Pub- lication TS-77-201, February, 1980. 21. BIKEWAY PLANNING CRITERIA AND GUIDELINES, State of California, Division of Highways, University of California at Los Angeles, April, 1972. 22. REGIONAL WORKSHOPS ON BICYCLE SAFETY: PRESENTATIONS, PARTICIPANT PROBLEMS, PROGRAMS AND IDEAS, AND RECOMMENDATIONS, DOT HS-803 658, Vincent S. Darago, September, 1978. 1 1 1 EXHIBIT 13 COSTS OF INTERIM MEASURES Costs for implementing the interim measures listed in the text are based on actual invoice costs, wherever possible. Estimates have been made for the costs of existing maintenance personnel to perform adjustments and testing based on our experience as to the time required including travel times. Adjust existing detector sensitivity $ 0 - 25.00 Adjust minimum time or set recall $ 0 - 25.00 Check terminal blocks and screws $ 0 - 25.00 Check loop and lead-in splices $ 25 - 100.00 Test loop and lead-in combination $ 25 - 100.00 "Megger" loop detector to ground $ 25 - 100.00 Install new detector amplifier $100 - 200.00 Mark detector with bicycle symbol $ 25 - 35.00 Install pedestrian push buttons $ 70 - 120.00 31 1