Effective Coordination with Towing Companies for Incident Response and Clearance

Tow truck operators are directly exposed to traffic when responding to incidents. In addition, stalled vehicles on the highway can hinder safety and operations on the highway and can create a risk of secondary incidents. Fast and effective removal of stalled vehicles on the highway can improve traffic operations and safety for tow truck operators and all users of the transportation system. The objectives of this research study are to synthesize existing department of transportation (DOT) practices regarding coordination with towing companies and to identify potential collaboration and training opportunities that will improve towing worker safety as well as traffic safety by improving incident response and clearance. The research methodology to meet this objective includes a literature review, survey, and coordination with the tow trucking industry, specifically the Missouri Tow Trucking Association (MTTA). Results indicate that training programs (26 responding DOTs) and coordination with the state towing association (23 responding DOTs) are the strategies most used by responding DOTs for partnering with the towing industry. Eight responding DOTs have implemented a Towing Recovery Incentive Program (TRIP) that provides incentive payments for towing companies to clear incidents within a specified timeframe. DOTs have found TRIPs to be beneficial in clearing incidents sooner. During an informal focus group as part of their monthly meeting, MTTA provided feedback on various topics, such as communication needs, interest in training, and the need for regulations that improve the quality of tow operators. The research identified potential opportunities for MoDOT and the State of Missouri to enhance its coordination practices with MTTA, such as including the towing industry in the planning process for major projects, implementation of regulations for requirements of tow operators, and partnering to strategize on how to best manage incidents involving electric vehicle fires.

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Report number: cmr 25-014
Published: September 2025

Project number: TR202514

Authors: Henry Brown, Carlos Sun, and Zhu Qing  

Performing organization: University of Missouri-Columbia

Assessment and Repair of Prestressed Bridge Girders Subjected to Over-height Truck Impacts

This research investigates the impact of over-height vehicle collisions on prestressed concrete bridge girders and explores effective repair strategies to restore their structural integrity. The study addresses a critical concern in bridge resilience, as vehicle impacts can cause varying degrees of damage and severe prestressing strands which compromise girder flexural strength and overall safety. A comprehensive approach was employed, integrating numerical modeling and experimental testing to assess damage mechanisms and evaluate the effectiveness of different repair techniques. Key findings include the determination of equivalent static force for semi-tractor trailers and rigid objects. Shear failure was identified as the dominant failure mode of prestressed concrete girders under impact loading. Additionally, accidental lateral eccentricity was found to reduce flexural resistance, necessitating a 15% reduction factor in AASHTO LRFD guidelines. A practical technique for measuring residual prestress forces was developed and validated with an experimental test and found to be conservative by 9.4%. Repair methods using mechanical strand splicing successfully restored up to 95% of the original strength for strand losses ranging from 17% to 33% using innovative confinement techniques. Moreover, externally bonded carbon fiber-reinforced polymer (CFRP) repairs fully restored flexural strength for up to 33% strand loss, with an additional strength reserve of 15%–23%.

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Report number: cmr 25-013
Published: September 2025

Project number: TR202011

Authors: Haitham AbdelMalek, Francis Ashun, Mohamed Elshazli, Mohanad Abdulazeez, Ahmed Gheni, Ahmed Ibrahim, and Mohamed ElGawady

Performing organization: Missouri University of Science and Technology