Early Daylight Savings and Traffic Signals...
Rick Zygowicz of the Wisconsin Section posted this timely warning (pun intended!) as part of ITE Wisconon News and Events:

The results of a brief survey have shown that only a small percentage of agencies that operate and maintain traffic signals have taken action to prepare traffic signals for the changes to Daylight Savings Time (DST) that take effect this year.

The 2005 Energy Policy Act has extended DST by one month. Previously DST took effect for most of the United States at 2 a.m. on the first Sunday of April and reverted to standard time at 2 a.m. on the last Sunday of October. Beginning this year DST begins for most of the United States at 2 a.m. on the second Sunday in March (March 11th) and reverts back to standard time at 2 a.m. on the First Sunday of November (November 4th).

If no action is taken traffic signal controllers may have incorrect time settings from March 11th - April 1st and October 28th - November 4th; resulting in Time of Day signal timing plans being offset by one hour on the dates indicated. Peak hour timing plans offset by one hour could potentially increase traffic delays at signalized intersections. It is recommended that this information be passed along to state and local agencies involved in the operation or maintenance of traffic signals to encourage appropriate action to be taken.

Agencies should be advised to check their system documentation to determine how these changes will effect the operation of their system(s). One or more of the following actions may be necessary:

> Controllers with programmable DST settings -- Update the settings to reflect the new implementation dates prior to March 11th. Verify that the changes take effect and monitor the operation of the system particularly on the dates of March 11, April 1, October 28 and November 4, 2007.

> Controllers without programmable DST settings connected to a central system or external time source -- Contact controller manufacturer for availability of firmware or software update; install update prior to March 11th. If firmware or software update is not available; disable DLS feature on controller and implement time update from central system or external time source. If DST feature cannot be disabled; implement time update from central on March 11th and verify time settings on April 1st, October 28th and November 4th.

> Controllers without programmable DST settings not connected to a central system or external time source -- Contact controller manufacturer for availability of firmware or software update; install update prior to March 11th. If firmware or software update is not available; disable DST feature on controller and implement time update manually on March 11th. If DLST feature cannot be disabled; implement time update manually on March 11th and again on April 1st, October 28th and November 4th.

For more information on this subject or this survey, please contact:
Eddie Curtis, P.E.
FHWA Resource Center
61 Forsyth St SW Suite 17T26
Atlanta, GA 30303
(404) 562-3920
http://ops.fhwa.dot.gov/arterial_mgmt/index.htm