CHAPTER 6

Conclusion

Bridge and tunnel strikes (BrTS) damage infrastructure, damage vehicles and cargo, create traffic delays, disrupt access to communities, and kill and injure people. For motor carriers, BrTS crashes have the potential to result in insurance increases, safety rating drops, operator termination, and direct responsibility to pay for the cost of repairs. While BrTS crashes can be catastrophic, there have been several challenges to addressing these crashes, including underreporting of crashes, low crash density (crashes spread across the network), and data quality issues. Further, BrTS crashes are complex and may involve several diverse contributing factors, such as roadway characteristics, bridge or tunnel characteristics, driver or human factors, and vehicle and load factors. Some of these factors are location-specific (e.g., roadway and bridge characteristics), while others could occur randomly (e.g., unsecured load) or propagate throughout the system (e.g., inattentive driver). This guide provides a foundation for identifying priority (high-risk) locations; diagnosing BrTS risk factors; and planning, prioritizing, implementing, and evaluating multidisciplinary strategies to mitigate BrTS risk. By diagnosing BrTS risk and crash contributing factors, agencies can better target engineering, operational, education, outreach, and enforcement policies and strategies to address those specific underlying factors. By quantifying BrTS risk and considering safety alongside other performance measures (e.g., resilience), agencies will better understand the comprehensive costs and benefits of projects, which will lead to more informed decisions and impactful investments.

The following is a list and summary of opportunities to employ this guide in practice:

• Identify high-risk BrTS locations.
• Diagnose BrTS contributing factors.
• Select and prioritize countermeasures to mitigate BrTS risk.
• Evaluate the effectiveness of BrTS projects and programs.
• Enhance BrTS data and analysis capabilities.

Identify high-risk BrTS locations. The first step to addressing BrTS risk is to locate each crash to the respective bridge or tunnel. The guide describes various methods for locating crashes as well as the strengths and limitations of those methods. There are also various options for prioritizing bridges and tunnels, including crash-based and risk-based methods. The guide describes the challenges in using traditional crash-based methods and the value of using a risk-based approach to assess the vulnerability of the infrastructure and proactively mitigate BrTS risk.

Diagnose BrTS contributing factors. Before an agency identifies countermeasures, it is important to understand the factors contributing to and associated with BrTS risk. This guide provides an overview of risk-based assessments and a list of common factors that increase BrTS risk. It also includes data collection and analysis procedures that agencies could use to identify jurisdiction-specific risk factors and assess BrTS risk based on state, regional, or local data.

Select and prioritize countermeasures to mitigate BrTS risk. Once an agency identifies BrTS contributing factors, the next step is to identify appropriate countermeasures to target the underlying issue(s). This guide provides a list of common engineering, operational, education, outreach, and enforcement policies and strategies to address specific BrTS risk factors. The guide also includes detailed descriptions and information on the applicability, effectiveness, and cost of the various countermeasures. This will help practitioners identify appropriate options to address the issue at hand. The guide provides methods to pare down the initial list of options to the preferred alternative through the analysis of alternatives. This supports the development of agencywide strategies and procedures to mitigate BrTS risk.

Evaluate the effectiveness of BrTS projects and programs. The final step is to evaluate projects and programs to understand their effectiveness and return on investment. This guide describes fundamental concepts for tracking and evaluating projects and programs, including measures of effectiveness, methods, and data needs. Agencies should then use the evaluation results to inform future funding and policy decisions.

Enhance BrTS data and analysis capabilities. Beyond the analysis of jurisdiction-specific issues, there is a need for agencies to provide accessible data and information for external users. This guide describes opportunities for agencies to contribute data to a national BrTS Clearinghouse to improve the completeness, accuracy, and accessibility of a comprehensive and up-to-date inventory of BrTS data. This will support national efforts, such as cross-jurisdiction truck routing, BrTS research, and BrTS tracking and reporting. Given complete and quality data, the national BrTS Clearinghouse can provide estimates of the risk (i.e., likelihood and consequences) of a BrTS crash based on bridge, tunnel, roadway, and operational characteristics. Transportation agencies can then use this information to identify roadway, bridge, and tunnel locations for potential infrastructure improvement projects. Commercial motor vehicle enforcement officials can use this information to identify risk factors and potential locations for implementing enforcement strategies. Motor carriers can use this information to identify routes that are higher risk and instruct their drivers to avoid such routes, and researchers can use the BrTS Clearinghouse to advance the state of the practice for identifying and addressing BrTS risk.