The St. Louis Motorist Assist program had a benefit-cost ratio of 38.25:1, with annual secondary crashes lowered by 1,082 and annual congestion costs lowered by $1,130,000.

Analysis of safety data on highways from 2000-2008 in the St. Louis metro area

February 2010

Summary Information

A key element to incident management in the St. Louis, Missouri metro area is the Motorist Assist (MA) program. MA’s mission is to reduce delays and improve safety by keeping interstate highway lanes clear of disabled vehicles. MA works in coordination with local law enforcement, emergency responders, and private towing agencies in incident response and recovery.
To patrol St. Louis's metro area, MA uses 12 trucks and operators per shift, and covers over 160 center lane miles of six interstate highways and one freeway every day from 5:00 a.m.-7:30 p.m. (excluding some major holidays). On an annual basis, MA operators patrol over a million miles, making over 31,000 stops each year. The MA program was the first ITS freeway management program in St. Louis and Kansas City, having deployed cameras, communication equipment, message boards and traffic sensors to support incident detection and verification, and response and recovery.


The benefit-cost analysis used safety data from incidents that occurred from the years 2000-2008 on seven freeways in the metro St. Louis area. The analysis used data that law enforcement responders had provided on the Missouri Uniform Accident Report (MUAR) at the scene. A key component to the analysis was estimating the impact of secondary crashes on the benefit-cost ratio. The analysts considered a crash secondary if it occurred at a close proximity upstream from the primary incident, and had occurred recently after the onset of the primary incident. The analysis found that the secondary crashes on average had more severe characteristics than primary incidents, with a higher percentage of fatal and Property Damage Only (PDO) crashes. The higher severity in secondary crashes increased the valuation of average crashes to $72,350 per crash in 2009 dollars, compared to the 2002 valuation of $30,000 per crash used for the previous benefit-cost analysis of the MA program in St. Louis.


A benefits-cost analysis of the expanded St. Louis Motorist Assist (MA) program found, not surprisingly, that the program had increased benefits and costs as it expanded, but the benefits increased much more than the cost. The analysis found that the program produced an annual benefit-cost ratio (B/C) in 2009 dollars of 38.25:1. This result is a very large increase over the 2003 B/C of 11.2:1. A significant benefit realized by the program was a reduction in secondary crashes, which resulted in a decrease of 1,082 secondary crashes per year, an annual net social benefit of $78,264,017 and a reduction of annual congestion costs of $1,130,000.

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Evaluation of Freeway Motorist Assist Program: Final Report

Author: Sun, Carlos; Chilukuri, Venkat; Ryan, Tom; Trueblook, Michael

Published By: MoDOT

Source Date: February 2010



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Related Metropolitan Integration Links

Link 13: Freeway Management to Incident Management

Typical Deployment Locations

Metropolitan Areas


freeway service patrol, courtesy patrols, highway helpers, freeway service patrols

Benefit ID: 2011-00666