AGENDA #5c

MEMORANDUM

TO:                  Mayor and Town Council

FROM:            W. Calvin Horton, Town Manager

SUBJECT:      Follow-Up Report Regarding Installation of Traffic Signal Activation Loops for Bicycles at Signalized Intersections

DATE:                        April 5, 2005

This is a follow-up report in response to a petition submitted by the Bicycle and Pedestrian Advisory Board requesting the installation of traffic signal activation loops to accommodate bicycles at signalized intersections. 

Currently, the Town is in the process of updating several traffic signals on Rosemary Street using 2003 Bond Funds.  We will include changes in loop detectors at these locations to recognize the presence of bicycles where it is practical to do so.

BACKGROUND AND DISCUSSION

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. At its March 22, 2004 meeting, the Council received a staff report responding to the petition and noting that the traffic signal loop detectors on Ransom Street at Cameron Avenue would be redesigned to detect bicycles.  We also advised the Council that we would provide a follow-up report in six to nine months regarding effectiveness, costs, maintenance problems, and citizen reactions to the bicycle-sensitive loops at this location.  Attachment #1 is a copy of the March 22, 2004 staff report.

Standard vehicle detection loops are designed to actuate traffic signals in response to the presence of motorized vehicles (including most motorcycles and motorbikes) that are constructed largely of ferrous metal.  It is the metallic mass of vehicles that is detected by the loops.  Non-motorized vehicles such as bicycles do not have a sufficient mass of ferrous metal to be detected by typical traffic signal loops.

We have tested a modified vehicle detection loop on Ransom Street at Cameron Avenue, and determined that its sensitivity could be tuned to detect a bicycle waiting at the intersection in most cases.  Recently, we have installed pavement markings and a sign as shown in Attachment #1 to inform bicyclists of the loop detector. 

The Town staff conducted before and after reviews of functional conditions at the intersection, including level of service, and found no significant change in the operational capacity of the intersection. We believe these results are mainly due to the low traffic volume on Ransom Street at this intersection, and the available gaps in the traffic on Cameron Avenue allowing right turns on red.  We have received several calls from bicyclists expressing satisfaction with the revised detector loop design on Ransom Street.  The cost of installing a traffic signal loop capable of detecting bicycles is approximately $1200.  This compares to a cost of approximately $700 for a standard vehicle detector loop installation.

To date, the North Carolina Department of Transportation has not identified acceptable equipment and installation standards for bicycle detection loops at signalized intersections on State roads.  The State is concerned that overall intersection efficiency would be significantly reduced in many cases if bicycle loop detectors were installed.  However, State staff has agreed to consider requests for bicycle loop detectors based on specific intersection locations and operational characteristics.

We will continue to evaluate signalized intersections on local streets to determine if the installation of bicycle detector loops would be practical.  We will also work with State staff to give similar consideration to bicycle loop detector installations at signalized intersections on State roads.

ATTACHMENTS

1.     March 22, 2004 Council Report (p. 3).