Memorandum

City of Lawrence

Public Works

TO:	David P. Cronin, P.E., City Engineer
FROM:	Zachary D. Baker, P.E., Project Engineer
DATE:	December 31, 2015
RE:	9th Street, Emery Road to Mississippi Street Corridor Crash History Analysis 9th Street Signal Coordination

Background

The City of Lawrence applied for 2013 Highway Safety Improvement Program (HSIP) funds from KDOT to improve safety at the intersections of 9th & Emery Road and 9th & Michigan Street. There had been safety concerns for traffic making left turns on Emery Road and on Michigan Street from 9th Street. The city was awarded funds from KDOT and city staff put together plans for a project at those intersections that included street and signal improvements along with a lane reconfiguration where the existing 4-lane section was restriped to a 3-lane section. One through lane was designated for east and westbound traffic along the corridor with a center turn lane and bike lanes. This 3-lane section was extended from just west of Emery Road to west of Mississippi Street. This project construction began in late July of 2014 and was finished by September 18, 2014.

City staff reviewed crash history data from 2011 to present to determine if the number of crashes throughout the corridor per year have decreased with the newly constructed lane configuration. Results of the crash history analysis are discussed below.

Crash History Analysis

A breakdown of the crash data is shown in greater detail for each intersection within the corridor in the spreadsheet attachment with this memo. A basic summary of the crash data is listed below:

• Average crashes / year in the corridor 3 years prior to 3-lane construction = 29
• Total crashes in 1 year after the 3-lane construction = 24 (17% Reduction)

The 3-lane road configuration project was complete by September 18, 2014. Crash data was studied from that completion date to 3 years prior on that date, as well as one year after, to obtain a before and after crash history summary. A review of all accident reports and statements showed that in the last 4 years (112) crashes has occurred between Emery Road and Mississippi Street.

In 3 years before the 9th Street project there was an average of (29) crashes in the corridor per year. In the year after the project (24) crashes occurred. This is about a 17% decrease throughout the corridor project.

Intersections of 9th Street at Arkansas Street, Alabama Street, and Illinois Street typically did not have many crashes before or after the lane reconfiguration.

Intersections of 9th Street with Michigan Street and Missouri Street showed some improvement after the lane reconfiguration. These are unsignalized intersections that previously had seen several rear end style crashes occur on 9th Street while vehicles waited to make left turns on the side streets. Crash totals for the remaining intersections were within the degree of variance and were typically no different after the lane reconfiguration project.

Signal Coordination

After recent evaluation of traffic counts this fall, the signal timing of the three 9th Street intersections in the corridor (Emery, Maine and Mississippi) was recently modified to operate in a coordinated system during the AM and PM peak hours. Staff will continue to evaluate and optimize signal timing on 9th Street in addition to collecting annual data on crash history.