City
of Lawrence
TRAFFIC
ENGINEERING DIVISION
MEMORANDUM
TO: Charles Soules,
Director of Public Works
Terese Gorman, City Engineer
FROM: David Woosley,
Transportation/Traffic Engineer
DATE: 9
May 2006
SUBJECT: Traffic Safety Commission
At
the March 6, 2006, Traffic Safety Commission meeting, the commission heard a
request to implement protected-permissive left-turn phasing for
The
traffic signal at 34th Street & Iowa Street is coordinated with
the other traffic signals along Iowa Street using a 120-second cycle length;
therefore, a vehicle entering the left-turn lane could wait as long as 120
seconds before receiving a left-turn arrow.
During high traffic periods a 2 minute wait doesn’t seem that long
because some traffic will be moving at all times; however, during low traffic
periods, a 2 minute wait seems much longer if there is little or no
traffic. Protected-permitted left-turn
phasing would allow left-turning vehicles to turn left during the left-turn
arrow phase and during the straight-through green-ball phase after yielding to
other traffic. Protected-permitted
left-turn phasing is currently in place at many intersections in
The
Traffic Safety Commission recommended on a 5-1 vote that protected-permissive
left-turn phasing be implemented on a trial basis until the intersection meets
the established criteria for protected-only phasing.
If additional information is needed, please let me know.