BACKGROUND
Bridge/tunnel strikes inflict serious damage to vehicles (including commercial motor vehicles, recreational vehicles, buses, and agriculture and industrial equipment) and highway bridges/tunnels, cause injuries and fatalities in initial and secondary crashes, impose detours and costly delays on other highway users, and require expensive incident responses from bridge/tunnel owners, state departments of transportation (DOTs), and public safety agencies. Attempts to prevent bridge/tunnel strikes include signing, lighting, height detection systems, and actuated warning devices. These measures have achieved limited success.
Lack of comprehensive information on the number, location and severity of bridge/tunnel strikes contributes further to the problem. By one estimate, more than 3,200 bridge/tunnel strikes occurred during the period of 2007 – 2017 at a cost approaching $1 billion, but this estimate does not include all states. Many bridge/tunnel strike collisions are unreported and may go undetected until the next scheduled bridge/tunnel inspection. Even reported collisions may not be reported as bridge/tunnel strikes, because no standard “check box” exists on crash report forms. Lack of information limits understanding of the frequency, impact, causation, and potential mitigation of bridge/tunnel strikes.
After the I-5 Skagit River Bridge collapse in Washington in 2013, the National Transportation Safety Board, in NTSB Safety Recommendation H-14-008, recommended development of:
"A best practices guide that the states can use to prevent bridge strikes by overheight vehicles. At a minimum, the guide should include:
- a framework for collecting bridge strike data and for ensuring communication of these data among the state agencies responsible for conducting bridge inspections and those responsible for issuing oversize load permits, to support the development of countermeasures;
- practices for using the data to develop operational changes;
- methods for evaluating bridge strike countermeasures; and
- a review of countermeasures that have proven effective in reducing the number of bridge strikes by overheight vehicles in the states and in other countries."
OBJECTIVE
The objective of this research was to develop a guide to help state DOTs, public safety agencies, and the motor carrier industry prevent and mitigate the risk of bridge/tunnel strikes by motor vehicles. At the minimum, the research team was tasked to:
- develop a sustainable national clearinghouse for collecting and analyzing data, and communicating bridge/tunnel strike data and bridge/tunnel clearance information. This clearinghouse will be used to store and maintain data collected under this project and future data collected by other agencies after completion of this project;
- identify and evaluate the nationally and internationally implemented countermeasures to prevent bridge/tunnel strike;
- develop a risk-based data driven approach to evaluate the risk of bridge/tunnel strike;
- develop prevention and mitigation strategies that consider bridge/tunnel design, policy and operation, and utilizing technologies to prevent bridge/tunnel strike;
- analyze the relationship between the vehicle permitting processes (including roadway network dimensions, oversize vehicle routing systems, routing compliance for oversized loads, and pilot car escort guidance ) and bridge/tunnel strike;
- develop training and outreach materials for motor carrier industry, traffic operation groups, vehicle permitting, and public safety agencies; and
- develop a roadmap for state DOTs and other transportation agencies to implement and maintain the national clearinghouse for data collection after completion of this project.
STATUS: The final deliverables will be published as NCHRP Research Report 1132 and NCHRP Web-Only Document 411.
