AGENDA #5d

MEMORANDUM

TO:                  Mayor and Town Council

FROM:            W. Calvin Horton, Town Manager

SUBJECT:       Response to a Petition from the Bicycle and Pedestrian Advisory Board Requesting Installation of Traffic Signal Activation Loops for Bicycles at Signalized Intersections

 

DATE:             March 22, 2004

 

 

This report responds to a petition submitted by the Town Bicycle and Pedestrian Advisory Board requesting installation of traffic signal activation loops to accommodate bicycles at signalized intersections.  Attachment 1 is a copy of the petition. 

 

BACKGROUND

 

At its January 12, 2004 meeting, the Town Council received and referred a petition from the Bicycle and Pedestrian Advisory Board requesting the installation of traffic signal activation loops for bicycles at signalized intersections. The petition requests the following:

·        Ensure that existing traffic signal loops are set to detect bicycles

·        Install markings for bicycle traffic signal activation loops

·        Include bicycle-friendly signal activation loops in future construction projects

 

The Board also requests that traffic signal activation loops for bicycles be installed initially at the following locations:

·        On Ransom Street at Cameron Avenue

·        On McCauley Street at Pittsboro Street

·        On McCauley Street at South Columbia Street

 

Please see Attachment 2 for an area map showing these locations. 

 

DISCUSSION

 

There are two primary types of traffic signals in the Town: (1) pre-timed; and (2) demand-actuated.  Pre-timed signals change from green to yellow to red to green, etc. based on a time cycle set in the controller. In other words, if pedestrians or cyclists or drivers are stopped at a pre-timed signal, and wait for the light to go through its cycle, they can proceed on a green light after however many seconds are set for the signal to cycle through the red/yellow/green light changes.  Chapel Hill has six intersections with traffic signals that operate under some form of pre-timed control.  Pre-timed traffic signals typically do not create delay problems for bicyclists because the signal will cycle independently without vehicle detection loop commands.

 

Alternatively, demand-actuated signals do not operate on a set time cycle, and they change in response to commands from vehicle detection loops set in the pavement at the intersection approach(es).  Most traffic signals in the Chapel Hill-Carrboro system are demand-actuated. 

 

Standard traffic vehicle detection loops typically used at demand-actuated signals in our system are designed and constructed to actuate traffic signals in response to detection of the presence of most motorized vehicles (including motorcycles and motorbikes) that are constructed largely of metal.  It is the metallic mass of vehicles that is detected by the signal actuation loops.  Standard non-motorized bicycles do not have sufficient metallic mass to be detected by typical traffic signal loops.

 

At two locations in the Town we are testing microwave-type vehicle detectors.  This type of vehicle detection has not to date been found feasible or practical for bicycle detection.

 

Also, we have in the past tried video-type vehicle detection systems using traffic cameras but, due to operational problems with the equipment, the cameras had to be removed and replaced with standard loop detectors in the pavement.

 

We have received requests in the past to install bicycle detection loops on State roads in Chapel Hill.  These requests have been denied by the North Carolina Department of Transportation because it has not identified an equipment and installation standard for bicycle detection that is acceptable for use on State roads.  The State has expressed and continues to express concern that overall intersection efficiency would be significantly reduced primarily due to spurious calls from existing loop technology that is sensitive enough to detect bicycles.  The only alternatives offered by the State are for cyclists to use push buttons where available, and/or to wait for a motorized vehicle to approach the intersection and be detected by the loops.

 

The Bicycle and Pedestrian Advisory Board requested that traffic signal loops initially be installed at three locations as noted above.  Changes to the signal loops at two of the locations (McCauley Street/Pittsboro Street and McCauley Street/South Columbia Street) must be reviewed and approved by the State.  We have requested that the State consider changes to include bicycle detection in the vehicle detection systems at these intersections.  We expect a response from the State within the next 90 days, and we will notify the Council and the Board of that response when we receive it.

 

The intersection and traffic signal at Ransom Street and Cameron Avenue is controlled solely by the Town, and we believe that we can redesign the signal loops on the Ransom Street approach to detect bicycles.  This signal does not have pedestrian phasing, so cyclists are unable to rely on the use of push buttons at this location.  Therefore, we propose implementing revisions in the existing signal loop design as shown in Attachment 3.  We think that the proposed changes would provide satisfactory bicycle detection at this location, as requested by the Board. 

 

The existing traffic signal cabinet and controller can accommodate the proposed changes in loop design.  Also, we propose placing signs and markings in accordance the Manual on Uniform Traffic Control Devices (MUTCD) for bicycle detection loop installations.  Please see Attachment 4 for the proposed markings and signs.

 

CONCLUSION

 

We believe that Ransom Street at Cameron Avenue is good location to test bicycle detection traffic signal loops.

 

Unless otherwise directed by the Council, we will proceed to redesign the signal loops on Ransom Street at its intersection with Cameron Avenue to detect bicycles.  We will perform a before-and-after evaluation of this intersection including general operations and service level, loop effectiveness, maintenance costs and/or problems, and citizen reactions.  After six to nine months of operation, we will report back to the Council with our findings about the operation and effectiveness of the bicycle detection signal loops.

 

We expect to complete the work by the end of April, including loop installations, markings and signs. We think that the total cost of the project will be approximately $2,000.  Funds for this project are available in the current Public Works traffic signal maintenance budget.

 

ATTACHMENTS

 

1.      Petition (p. 4).

2.      Area Map (p. 7).

3.      Bicycle Detected Loop Design Details (p. 8).

4.      Markings and Signs for Bicycle Detected Signal Loops (p. 9).