CHAPTER 1

Introduction

Sustaining a dynamic economy relies heavily on transportation, especially the movement of heavy tractor-trailers, which serve as the lifeblood of our economy. Despite the challenges posed by the pandemic, freight transportation, fueled by increased demand from e-commerce and home deliveries, remains stable. However, this growth in heavy truck traffic, coupled with larger trucks carrying heavier loads, poses a significant risk to road safety, even during the pandemic, raises concerns about road safety.

BrTS not only damage infrastructure but also disrupt traffic and pose hazards to drivers and passengers. In Texas, the average annual repair cost from bridge strikes over the past 3 years has been $6.7 million, while in Virginia, bridge strikes have cost about $4 million since January 2018 (Bergal 2019). Nationally, the average number of bridge hits exceeds 15,000 per year, as recorded by the National Highway Traffic Safety Administration (NHTSA, n.d.). The Federal Highway Administration (FHWA) identifies bridge-vehicle collisions as among the most common causes of bridge failure (FHWA, n.d.-a). Despite technological advancements, such as unmanned vehicles and transportation automation, preventing BrTS remains a challenge. To address this, a comprehensive inventory of BrTS, risk assessments, data-driven solutions, and agency-wide strategies are essential.

Factors contributing to BrTS include aging infrastructure, also recognized as “functionally obsolete”, and the increase in fleet size and weight. As early as 1973, Hilton investigated crashes involving highway bridges in Virginia and listed “inadequate vertical clearance” as one of the key contributing factors (Hilton 1973). In the 80s, Shanafelt and Horn authored two NCHRP reports on damage evaluation and repair methods for prestressed concrete bridges and steel bridges, respectively (Shanafelt and Horn 1980; 1984). In the 90s, some state DOTs started to develop procedures and methods to quantify the vulnerability of bridges to collision damage, including the Collision Vulnerability Assessment Procedure (CVA) of New York State DOT (NYSDOT, 1995). Recent trends show an increase in bridge deficiencies, with 9.1% of the nation’s bridges being structurally deficient and 13.6% functionally obsolete (ASCE 2017). Another major contributor to BrTS is truck drivers’ risky behavior and errors, including inattentiveness, non-compliance with regulations, and inaccurate load measurements (FMCSA, n.d.). On the other hand, inadequate signage and route planning also contribute (Agrawal, Xu, and Chen 2011).

Our understanding of the problems and challenges has identified the following as keys to the proposed project’s success:

1. Maintaining accurate and updated structure data, addressing issues of missing or erroneous information.
2. Establishing reliable linkage between BrTS and inventory data, overcoming challenges of data silos and varying Model Minimum Uniform Crash Criteria (MMUCC) compliance.
3. Extracting relevant data for collision risk analysis from complex interconnected databases.
4. Developing proactive methods to assess collision risk and improve response efficiency.
5. Quantifying the efficacy of safety countermeasures to inform infrastructure investment decisions.
6. Enhancing communication among stakeholders to improve BrTS mitigation efforts and data quality.

Goals and Objectives

The overall goal is to develop tools that facilitate collecting, analyzing, and communicating BrTS data to help state DOTs, public safety agencies, and the motor carrier industry prevent and mitigate the risk of

BrTS by motor vehicles. Although vehicles of all sizes can strike a bridge/tunnel, a large vehicle (e.g., a truck or bus) will create far more damage than a smaller vehicle traveling at the same speed striking the structure in the same way. Therefore, this project focuses on trucks with the aim to accomplish the following objectives:

1. Establish a national clearinghouse for BrTS data, facilitating collection, analysis, and communication of information for ongoing use by stakeholders.
2. Evaluate BrTS countermeasures implemented globally and nationally.
3. Develop a risk-based approach to assess BrTS vulnerability using data analysis.
4. Create prevention strategies considering design, policy, and technological solutions for BrTS.
5. Analyze the impact of vehicle permitting processes on BrTS incidents.
6. Produce training materials for stakeholders involved in BrTS mitigation.
7. Formulate a roadmap for maintaining the national clearinghouse post-project completion.

Report Outline

This research report describes the steps taken by the research team to develop the final guidebook and associated products for preventing and mitigating the risk of BrTS by motor vehicles, and to accomplish the previously described objectives. The outline of this research report is as follows:

• Chapter 1. Introduction
  • Discusses the background, objectives, and research method.
• Chapter 2. Literature Review
  • Reviews relevant literature.
• Chapter 3. Data Needs and Sources
  • Identifies data needs, data sources, and any associated challenges or limitations for developing methodologies and a sustainable national clearinghouse for BrTS data and clearance information.
• Chapter 4. Identify Knowledge Gaps Related to BrTS Data Management
  • Examines knowledge gaps related to BrTS, vehicle permitting processes, prevention and mitigation strategies, technologies, and data availability/quality, and provides a synthesis.
• Chapter 5. Data Acquisition, Processing, and Linkage
  • Describes the process of data acquisition from state and federal agencies and introduces the data processing and methodologies used for linking structure databases with crash data.
• Chapter 6. BrTS Data Analysis
  • Provides analysis results and descriptive statistics by crash injury severity, bridge parts, and state.
• Chapter 7. Methods for Risk Assessment
  • Presents three methods for risk assessment: basic method, expert knowledge and crash prediction models; documents six case studies; includes the crash prediction models for highway bridges developed within the scope of this project.
• Chapter 8. BrTS Data Clearinghouse Prototype
  • Illustrates the prototype of a BrTS data clearinghouse.
• Chapter 9. Countermeasures
  • Outlines the approach for selecting tailored safety measures for protecting bridges and tunnels from oversized vehicle strikes, based on diverse inputs and consultations.
• Chapter 10. Stakeholder Surveys
  • Presents the results of surveys and follow-up interviews with related stakeholders, mainly the state agencies and motor carriers from trucking industry.
• Chapter 11. Guide Development
  • Includes a proposed preliminary outline for a procedural guide for preventing and mitigating the risk of BrTS.
• Chapter 12. Conclusions and Recommendations
  • Presents the results of this research and recommends future research.