Mid-America Transportation Center


Date of this Version


Document Type



Report # MATC-MST: 341 Final Report 25-1121-0001-341


2011 Copyright of Mid-America Transportation Center


On January 2, 2008, the Missouri Department of Transportation (MoDOT) closed significant portions of Missouri Interstate 64 (I-64) in St. Louis County for reconstruction. During the planning stages of this project, the proposal to close all lanes of I-64 was met with public concern regarding the possible safety risks associated with diverting I-64 traffic to adjacent roadways. A specific concern was the possibility of increased crash rates on roads designated to receive I-64 traffic flow. The following research was conducted to assess the actual outcomes related to these concerns. Crash analyses and crash rate analysis of 2008 and 2009 crash data were performed. The data were compared to four years of pre-closure crash data. Overall results suggest no evidence of increased crash rates on roadways adjacent to I-64 resulting from the two-year closure period. The study indicated that crash rates on 17 roadways were 8.9% below average in 2008 and 14.7% below average in 2009. Crash rates declined for most freeways, expressways, and major arterials in the surrounding region. Rear-end crashes declined noticeably from 7,757 in 2007 to 6,728 in 2009.