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Iowa State University--Becoming the Best

Road Safety Audit for US 6 from Iowa City to West Liberty in Johnson and Muscatine Counties, Iowa

Narrow granular shoulders and worn edge lines


Principal investigator:

Project status


Start date: 10/14/08
End date: 06/05/09


Report: Road Safety Audit for US 6 from Iowa City to West Liberty in Johnson and Muscatine Counties, Iowa (28.23 mb pdf) June 2009


Sponsor(s): Iowa Department of Transportation

About the research


Approximately 13.2 miles of US 6 in eastern Iowa extends from the east corporate limits of Iowa City, Iowa, to the west corporate limits of West Liberty, Iowa. This segment of US 6 is a service level B primary highway, with an annual daily traffic volume varying from 3,480 vehicles per day (vpd) to 5,700 vpd. According to 2001–2007 crash density data from the Iowa Department of Transportation (Iowa DOT), the corridor is currently listed among the top 5% of non-freeway Iowa DOT roads in several crash categories, including crashes involving excessive speed, impaired drivers, single-vehicle run-off-road, and multiple-vehicle crossed centerline.

A road safety audit of this corridor was deemed appropriate by the Iowa Department of Transportation’s Office of Traffic and Safety. Staff and officials from the Iowa DOT, Iowa State Patrol, Governor’s Traffic Safety Bureau, Federal Highway Administration, Center for Transportation Research and Education, and several local law enforcement and transportation agencies met to review crash data and discuss potential safety improvements to this segment of US 6.

This report outlines the findings and recommendations of the road safety audit team to address the safety concerns on this US 6 corridor and explains several selected mitigation strategies.