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."
The objective of this research is 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 shall:
- 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.
Accomplishment of the project objective will require at least the following tasks.
Task descriptions are intended to provide a framework for conducting the research. The NCHRP is seeking the insights of proposers on how best to achieve the research objective. Proposers are expected to describe research plans that can realistically be accomplished within the constraints of available funds and contract time. Proposals must present the proposers' current thinking in sufficient detail to demonstrate their understanding of the issues and the soundness of their approach to meeting the research objective.
Task 1. Conduct a literature review of relevant research and current state of practice related to strike of bridge/tunnel and other highway structures; existing countermeasures including prevention and mitigation strategies; and roadside and onboard vehicle technologies. The review shall include published and unpublished research conducted through the NCHRP; FHWA; and other national, international, state, and pooled-fund sponsored research.
Task 2. Identify the data required, to be collected in Phase II, in order to achieve the research objective. The research team shall plan to collect field data, as needed, if data are not available.
Task 3. Synthesize the Tasks 1 and 2 to identify the knowledge gaps related to bridge/tunnel strikes, vehicle permitting processes, prevention and mitigation strategies, technologies, and data availability and quality. These gaps should be addressed in this research or as budget permits in the recommendations for future research.
Task 4. Propose a methodology to achieve the research objective, to be fully developed in Phase II.
Task 5. Propose a preliminary outline for the guide.
Task 6. Prepare Interim Report No. 1 that documents Tasks 1 through 5, includes the data archiving and sharing plan (see Special Note C), and provides an updated work plan for the remainder of the research. This report must be submitted to NCHRP no later than 4 months after contract execution. The updated work plan must describe the process and rationale for the work proposed for Phases II though IV.
Note: Following a 1-month review of Interim Report No. 1 by the NCHRP, the research team will be required to meet with the NCHRP project panel to discuss the interim report. Work on Phases II though IV of the project will not begin until authorized by the NCHRP. Phase I shall be limited to $40,000.
PHASE II—Data Collection and Methodology Development
Task 7. Collect and analyze data to achieve the research objective. Data should be augmented by documented research according to the approved Interim Report No.1. The research team is expected to collect and supplement unavailable data. The collected data shall be stored in a data clearinghouse to be hosted by the research team during the research.
Task 8. Execute the proposed methodology according to the approved Interim Report No.1.
Task 9. Provide a detailed description of every chapter and section of the proposed guide and complete a sample chapter of the proposed guidance selected by NCHRP. This chapter should be publication-ready.
Task 10. Prepare Interim Report No. 2 that documents the results of Tasks 7 through 9 and provides an updated work plan for the remainder of the project. This report is due no later than 12 months after approval of Phase I. The updated plan must describe the work proposed for Phases III and IV.
Note: Following a 1-month review of Interim Report No. 2 by the NCHRP, the research team will be required to meet in person with the NCHRP project panel to discuss the interim report. Work on Phases III and IV of the project will not begin until authorized by the NCHRP. Phase II shall be limited to $300,000.
PHASE III—Guidance Development
Task 11. Develop the guide according to the approved Interim Report No.2.
Task 12. Prepare Interim Report No. 3 that documents the results of Task 11 no later than 6 months after approval of Phase II. The updated work plan must describe the work proposed for Phase IV.
Note: Following a 1-month review of Interim Report No. 3 by the NCHRP, the research team will meet with the NCHRP project panel to discuss the interim report, if necessary. Work on Phase IV of the project will not begin until authorized by the NCHRP. Phase III shall be limited to $100,000.
PHASE IV—Final Products
Task 13. Present draft final deliverables to appropriate AASHTO technical committees for comments and propose any revisions to NCHRP.
Task 14. Prepare final deliverables including:
- a guide for preventing and mitigating the risk of bridge/tunnel strikes by motor vehicles;
- a final report that documents the entire research effort;
- the training and outreach materials for motor carrier industry, traffic operation groups, vehicle permitting, and other transportation agencies;
- the roadmap for state DOTs and other transportation agencies that describes how to implement and use the developed national clearinghouse for data collection after completion of this project;
- the national data clearinghouse including the data collected under this project; and
- a stand-alone technical memorandum titled “Implementation of Research Findings and Products.” See Special Note E for additional information.
The draft deliverables are due no later than 2 months after approval of Phase III.
Note: Following receipt of the draft final report, the remaining 3 months shall be for NCHRP review and comment and for research agency preparation of the revised final report. Phase IV shall be limited to $60,000.
STATUS: Research in progress
The research team is proceeding with Phase IV work.