Memorandum

City of Lawrence

Municipal Services and Operations

TO:	Tom Markus, City Manager
FROM:	Dave Cronin, City Engineer
Date:	November 20, 2018
RE:	19^th & Iowa Signal Timing

At the November 4^th City Commission Meeting Mayor Boley asked staff to review the signal timing at 19^th & Iowa.  The traffic signal operates in an actuated, coordinated system on Iowa with a cycle length of 120 seconds in the morning peak hour and 150 seconds in the afternoon peak hour.  The traffic signal can go out of coordination when preempted by emergency vehicles and can take several cycles to resynchronize. 

A traffic impact study was conducted by Professional Engineering Consultants prior to design of the 19^th Street reconstruction project.  The study did not recommend changes to the existing traffic signal phases, but did recommend geometric improvements including a southbound dual left-turn lane, a westbound dual left-turn lane, and a northbound right turn lane.  All three of these improvements are included in next year’s 19^th Street reconstruction project.  The study projected that these improvements would improve the overall level of service (LOS) at the intersection in the PM peak hour from LOS D to LOS C.  In addition, the pedestrian tunnels will eliminate the activated pedestrian phase and reduce vehicular delays.

19^th & Iowa Traffic Impact Study Summary