Highway / Railroad Signal Interconnect Seminar



  • The California Public Utilities Commission (CPUC), in conjunction with Railroad Controls Limited, Inc. (RCL), the Peninsula Corridor Joint Powers Board (Caltrain), Southern California Regional Rail Authority (Metrolink), and City of Los Angeles Department of Transportation will be offering a two-day seminar on interconnection of traffic signals with highway-rail grade crossing active warning devices.  The two-day seminar will be followed by half-day training on basics of highway-rail grade crossing design and California Manual on Uniform Traffic Control Devices (CA MUTCD) Part 8 (traffic control devices for highway-rail grade crossings) and Part 10 (traffic control devices at highway-light rail transit grade crossings).

Who Should Attend?

  • Traffic, Civil, and Signal Engineers – to learn about engineering components of integrating highway traffic signals with highway-rail grade crossing active warning devices, and also learn the basics of highway-rail grade crossing design and the requirements of the CA MUTCD.
  • Traffic Signal Maintainers – to learn how to avoid traffic signal maintenance problems that can lead to catastrophic crashes.
  • Public Works Managers and Supervisors and Transportation Planners – to learn about hazards and other issues associated with highway-rail grade crossings, in order to make better-informed decisions when planning or approving projects that involve highway-rail grade crossings.


  • Highway-Rail Grade Crossing Warning System and Traffic Signal Interconnection:
    April 11, 2007 and April 12, 2007 from 8:00 AM to 5:00 PM
  • Basics of Highway-Rail Grade Crossing Design and CA MUTCD:
    April 13, 2007 from 8 AM to Noon


  • Hiram Johnson State Building, Milton Marks Conference Center, 455 Golden Gate Avenue, San Francisco, CA.


  • Railroad Controls Limited, Inc. (RCL)
    N. Michael Choat, Vice President. Mike has 30 years experience in Railroad signal design and maintenance with the CSX Railroad.
    Scott Booker, Project Engineer. Scott has worked on numerous preemption projects throughout the U.S. with RCL, and was the traffic engineer for the city of Fort Worth in Texas prior to that.
    Peninsula Corridor Joint Powers Board (Caltrain)
    Raul Millena, Manager Signals and Communication. Raul is a member of Committees 36 (highway-rail grade crossings) & 37 (signal systems) of the American Railway Engineering and Maintenance of Way Association (AREMA).  He will also be one of the instructors of the two-day seminar.
  • Southern California Regional Rail Authority (Metrolink)
    Dan Guerrero, Manager Signals and Communication. Dan is also a member of AREMA Committees 36 and 37
  • City of Los Angeles, Department of Transportation.
    Sean Skehan, Principal Transportation Engineer, PE, PTO.
  • California Public Utilities Commission, Rail Crossings Engineering Section
    Varoujan Jinbachian, Senior Utilities Engineer
    Kevin Schumacher, Utilities Engineer. Varoujan and Kevin are the CPUC representatives to the California Traffic Control Device Committee (CTCDC), and are responsible for edits to Parts 8 and 10 of the CA MUTCD.  They will be the instructors for the half-day seminar on CA MUTCD.
  • Additional Guest Speakers (TBA)


  • Send an email to the address shown below providing the following information:
    Attending 2-day preemption seminar (Y/N):
    Attending 1/2 – day basic highway-rail grade crossing design seminar (Y/N):
    Public Agency (Y/N):
  • Fee: $250.00 (Fee waived for public agency employees)
  • Register early because seating is limited.
  • Email registration form to Denise Hecht at dhecht@railroadcontrols.com


  • Parking is limited; we encourage taking BART to the Civic Center Station and then a short walk through United Nations Plaza to the State Building located between Polk Street and Larkin Street on Golden Gate Avenue.
  • A limited amount of parking is available at public parking lots on Franklin Street between McAllister & Golden Gate Avenues, and Golden Gate Avenue between Gough & Franklin Streets.  $10 per day


  • A block of rooms has been set aside at the two hotels listed below.  Please make your reservations prior to the March 15th cut off date at both locations.  Reservations made after that time cannot be guaranteed at the stated rates.
  • Holiday Inn Civic Center – $110/night
    50 Eighth Street (at Market Street)
    3.5 blocks from site of conference and a short walk through the beautifully restored Civic Center plaza with the San Francisco City Hall, Main Library and Asian Art Museum.
    You may contact hotel reservations directly at (800) 243-1135.  Ask for the CPUC rate.  Or, attached is a booking link to facilitate your making reservations at the Holiday Inn. You may reserve your contracted rate directly through the reservation website by clicking below and entering the dates of your stay.  Holiday Inn notes that members of their Priority Club frequent travel rewards program also receive free breakfast in their restaurant when staying there.
  • Hilton Fisherman’s Warf – $140/night
    2620 Jones Street
    The Hilton Fisherman’s Wharf is approximately 2.3 miles from the conference site.  It is located in the beautiful Wharf/Marina area with many spectacular views and local restaurants.  Self or valet parking is available for an additional charge.  The block is listed under “CPUC” or “California Public Utilities Commission.” Reservations can be made through the hotel at 415-885-4700 or through their central reservations at 800-Hiltons (445-8667).
  • Additional Information: For additional information on the seminar or regarding lodging/logistics please contact Kevin Boles at (415) 703-2795 or kcb@cpuc.ca.gov.


Wednesday – April 11

  • 8:00 – 8:10 AM         Welcome / Introduction
  • 8:10 – 10:00 AM       Understanding Highway Traffic Signals
    Basic traffic signal control equipment types
    History    Fundamentals of operation
  • 10:00 – 10:15 AM     Break
  • 10:15 – 12:00 PM     Understanding Grade Crossing Warning Systems
    MUTCD – Responsibilities Fundamentals of operation Warning system types, Determining Warning Time
  • 12:00 – 1:00 PM       Lunch
  • 1:00 – 2:30 PM          Interconnection of the 2 Systems
    Preemption Operation, MUTCD definitions concerning preemption, MUTCD specific issues relating to preemption, adding the railroad to the 8 phase intersection
  • 2:30 – 2:45 PM          Break
  • 2:45 – 5:00 PM          Determining Preemption Time Requirements
    The Texas DOT Preemption Form Use of the Time Line    Solutions, the L.A. Preemption Form

Thursday – April 12

  • 8:00 – 8:15 AM         Review of Preemption Operation
  • 8:15 – 10:00 AM       Video Presentations
    Fox River Grove Issues
    The Fort Worth & Western Railroad at Mustang Drive
    The South Orient Railroad at Hulen Street
  • 10:00 – 10:15 AM     Break
  • 10:15 – 12:00 PM     Additional Preemption Issues
    Special Geometric Issues
    Queue Cutter Signals
  • 12:00 -1:00 PM         Lunch
  • 1:00 – 3:00 PM          Preemption Solutions – Putting New Technology to Work
    San Fernando Road – Serial Data Interconnect Circuit
    Railroad Issues
    Traffic Signal Issues
  • 3:00 – 3:15 PM          Break
  • 3:15 – 4:30 PM          Preemption Solutions – Putting New Technology to Work
    San Fernando Road at Roxford Street
    Live Demonstration
  • 4:30 – 5:00 PM          Metrolink Policies on New Preemption Projects

Friday – April 13

  • 8:00- 10:00 AM         Basics of Highway-Rail Grade Crossing Design
  • 10:00-10:15 AM        Break
  • 10:15 – 12:00 PM      CA MUTCD Parts 8 & 10

Bicycle Adaptive Traffic Signal Timing

I’m only an occasional bicycle rider but I have always thought that it would be nice if traffic signals could respond appropriately to the special characteristics of bicycles. Bicycles are different from cars. Among other differences are bicycles do not have air bags nor 5 mph bumpers. Forgetting that though, there are other differences between bicycles and motorized vehicles that need to be addressed. The three most important differences are acceleration, speed and stopping distance. A motorized vehicle can do all three better.

Still, there are good reasons to ride a bicycle. Better fuel economy, good exercise, less pollution, etc. are three very good reasons for riding a bicycle, especially for shorter expeditions.

Many people opt to utilize their bicycles and current rules of the road allow a mix of bicycles and motorized vehicles on the same roads. For many years there were no special considerations given to bicycles. More recently, some signals have installed special bicycle push buttons to provide bicycle timing. This requires the button to be located adjacent to the bicycle path or for the bicyclist to go to the pushbutton sometimes requiring dismounting. Not altogether convenient.

Many agencies made their inductive loop detectors sensitive to bicycles. The MUTCD has even been adjusted identifying bicycle detection requirements. This allows the bicycle to be detected but the timing provided is usually set for motorized vehicles rather than bicycles. There are often also other problems encountered unless special loops are utilized. A loop designed to pickup bicycles often will not detect trucks or SUV and or may detect cars in adjacent lanes causing improper traffic signal timing.

Often, two detector systems are installed in the traffic lane, one to detect bicycles one to detect other vehicles. Obviously this can be a costly method of detection. There are two things that would make things better for bicycles without adversely affecting motorized vehicles. One is bicycle adaptive timing. Adjust the traffic signal green and/or clearance time to be appropriate for the slower bicycle. In order to do this, a good means of detecting bicycles needs to be utilized. It would be better if the same loop detector system could discriminate a bicycle from other vehicles either by the signature of the actuation, amount of actuation, or special loop location.

Obviously, the easiest way is providing a special lane for bicycles that cars don’t travel over. This can be as simple as installing loops in the bicycle lanes. This does require that there is room for the bicycle lane, that bicycles use it and that cars don’t travel over it such as when making right turns.

A better approach is loop detectors that discriminate bicycle actuations from other vehicles. This is possible by providing a different output when the frequency variation of the loop array is low and a separate output or output condition when the actuation is greater. A typical bicycle causes 10-16hz frequency variation while a small car would be over 20 hz variation. Unfortunately, some other considerations need to be made to prevent false bicycle actuations due to cars passing near the loop rather than over it.

A better method would be to utilize an actuation signal signature difference to identify and discriminate bicycles from other vehicles and then provide the individual outputs for each. This should just be an adaptation of the typical counting detector operation. These detectors utilize loop arrays and only provide a single pulse for each vehicle that leaves the loop array. They have accuracies of greater than 98% and should be capable of providing bicycle discrimination with appropriate programming.

OK, now assume we have appropriate detection. Now, we need to adjust the traffic signal timing for the bicycle while still providing the least impact to the other traffic. There are three considerations. A bicycle starts out and accelerates much more slowly than other vehicles, doesn’t go as fast, and doesn’t stop as quickly. A traffic signal typically provides a minimum green time, a green extension time and a clearance time appropriate for the motorized vehicles. If the traffic controller could provide a different minimum green, green extension and clearance time adjusted appropriately for the lower acceleration and speed of the bicycle. Existing formulas can identify appropriate intervals, the key is having a controller that is capable of timing the intervals.

For example, a typical vehicle minimum green might be 6 seconds, green extension might be 3-6 seconds and a clearance interval 4.5 seconds for a roadway with a speed of 35 mph. When adjusted for a bicycle, the minimum green might be 8-10 seconds, green extension 6-10 seconds and the clearance interval of 5-8 seconds.

An important note here is that the vehicle clearance interval consists of both the yellow interval and the all red interval. The yellow interval should not be extended for the bicycle. The all red interval should provide the additional clearance. This is because motorized vehicle traffic could have difficulty responding to varying yellow clearance intervals since most drivers consider it green time and proceed to travel through the intersection on the yellow.

The Naztec model 920 traffic controller provides such timing. Reno A&E evidently has a bicycle discriminating loop detector system available. I haven’t seen the detector yet, but I’m told it exists and is in use.

Obviously, if the discriminating loop detector works, it really opens up adaptive bicycle timing. Even if a controller didn’t have any special timing capabilities, the detector could be set to provide different extension intervals for the two outputs allowing at least a bicycle appropriate green extension interval.

The real benefit of having a controller with bicycle timing capabilities is the ability to provide the extended clearance time for bicycles. At larger intersections, left turn travel distance can reach up to 180 feet. The amount of time it takes a bicycle to travel that distance could be more than 15 seconds. Typically, the motorized vehicle travels the distance in less than 6 seconds. Obviously, good practice doesn’t allow always having the longer interval for bicycles when they are not present.

To sumarize bicycles and other vehicles are different. Different timing needs exist for each. Methods now exist to provide for those differences.

For more information, try these links:

This is the first draft of this document and will probably be updated as errors and ommissions are identified. If you identify errors or can provide additional information please contact the editor using the contact form on the right sidebar or register and post a comment directly to this article.

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