Document Library

State and local transportation agencies increasingly rely on proactive safety analysis to inform roadway design and improvement decisions before crashes occur. However, uncertainty regarding the potential use of proactive safety methodologies, manuals, and guidance in tort litigation has raised concerns about increased exposure to liability.

NCHRP Legal Research Digest 95: Addressing Liability Issues of Proactive Safety Improvements, produced by TRB’s National Cooperative Highway Research Program, examines the legal considerations facing transportation agencies that adopt proactive, data-driven approaches to roadway safety. The digest reviews relevant statutes, case law, and agency practices; identifies litigation in which proactive safety concepts have been raised; evaluates defenses and outcomes; and documents strategies used by transportation agencies to mitigate liability concerns. Based on this analysis, the research explores potential legal, administrative, and policy approaches that may support the use of proactive safety methods while preserving established processes for prioritizing and funding roadway improvements.

This research describes a new method for work zone monitoring that allows for more continuous, accurate intelligence. The project focused on the design, deployment, and validation of a statewide, real-time work zone monitoring and traffic performance intelligence platform for Iowa known as ReactorIQ. Unlike traditional systems that depend on fixed roadside sensors, manual contractor logs, or delayed 511 updates, ReactorIQ is built around high-resolution connected vehicle (CV) telemetry as its primary data source. The platform continuously transforms naturalistic vehicle movement into detailed measures of mobility, safety, and operational performance across Iowa’s uninterrupted flow network, demonstrating that CV telemetry data can support a complete work zone intelligence workflow.

The TRC 2303 report presents a comprehensive analysis of the impacts of bridge closures across the Mississippi River in Arkansas, focusing on four key crossings: I-40, I-55, HWY 49, and HWY 82. Prompted by the emergency closure of the I-40 Hernando de Soto Bridge in 2021, the study evaluates both full and partial closures to quantify economic, safety, and mobility consequences. Using ARDOT’s Road User Cost (RUC) framework and the Arkansas Statewide Travel Demand Model (ARSTDM), the report estimates daily costs and system-level changes in Vehicle Hours Traveled (VHT) for autos, single-unit trucks (SUT), and tractor-trailer trucks (TTT). Partial closures of high-volume bridges like I40 and I-55 result in substantial daily costs, e.g., up to $2.4 million for I-40 along with widespread VHT increases. This is especially so for TTT, for which 6,902 miles of roadway exhibited more than a 4% increase in VHT under the I-40 closure scenario. In contrast, HWY 49 and HWY 82 closures had more localized effects, with HWY 82 showing the highest auto and SUT impacts but minimal freight disruption. Waterway disruption costs, derived from Automatic Identification System (AIS) data, also rose sharply between 2021 and 2024, with HWY 49 carrying the highest vessel volumes and HWY 82 showing the fastest growth. To support planning, the study delivered a web-based Bridge Closure Impact Analysis Tool that automates cost calculations and visualizes impacts. Mitigation strategies include operational measures, maintenance practices, and planning-based approaches, with partial closures recommended where feasible. Overall, the report equips ARDOT with data-driven tools to prioritize investments, manage emergencies, and maintain transportation resilience across river crossings.

This guide provides a structured roadmap for agencies seeking to implement performance-based contracting (PBC) to support proactive road asset management. Drawing on decades of international experience, it outlines how to design, scale, and manage PBC programs—from pilot projects to network-wide applications—across varying levels of agency maturity.

Practitioners will find guidance on using PBC to improve asset condition, enhance safety and resilience outcomes, and shift from reactive maintenance to performance-driven service delivery. The document also includes diagnostic approaches and implementation strategies that help agencies align contracting practices with broader TAM and performance management objectives.

This guide explains that safety is not just about the trains themselves, but also about how people get to and from stations . Problems often come from poor sidewalks, missing sign age, bad lighting, and busy roads near stations. Children, older adults, and people with disabilities are especially at risk. In some locations, crossings lack proper barriers or signals, increasing the chance of road crashes. Reliable data on crashes is also often missing, making it difficult to pinpoint where the greatest problems lie.

This document supports implementation of system-level transportation asset valuation, helping agencies translate asset inventories and condition data into meaningful measures of asset value. The resource provides case studies, worksheets, and outreach materials that demonstrate how agencies can apply asset valuation methods to support financial reporting, communicate infrastructure needs, and evaluate investment strategies.

Practitioners will gain practical guidance on using asset valuation to track system condition trends, demonstrate the impact of funding decisions, and strengthen transportation asset management (TAM) programs. The materials complement the AASHTO Asset Valuation Guide and include tools that help agencies integrate asset valuation concepts into planning, performance management, and investment decision-making.

This synthesis examines how State DOTs fund, manage, and coordinate the maintenance of Complete Streets infrastructure, including bicycle, pedestrian, and other active transportation facilities. As agencies expand multimodal networks, the report highlights practical challenges such as equipment compatibility, staffing capacity, and ongoing maintenance funding.

Practitioners will find examples of maintenance policies, interagency cost-sharing agreements, and partnership models involving local and tribal governments. The report also identifies strategies for workforce training, equipment procurement, and operational coordination that can help agencies sustain Complete Streets investments over time.

NCHRP Research Report 1149: Estimating Benefits of Closing Gaps in Active Transportation Networks: A Guide provides practical methods for evaluating the benefits of projects that improve connectivity in walking, bicycling, and rolling networks. Active transportation systems—including trails, sidewalks, bike lanes, and connected roadways—play a critical role in supporting safe, convenient travel for both recreation and everyday trips, yet many communities face fragmented networks with significant gaps. This guide offers accessible analytical approaches that can be applied across diverse geographies and project types, using publicly available datasets and research-based multipliers. Designed for broad usability, the methods rely primarily on national-level data sources to help agencies consistently estimate economic, safety, health, and mobility benefits.

NCHRP Web-Only Document 426, which accompanies the report, documents the development of the guide and summarizes the full research effort behind the recommended methodologies.

NCHRP Research Report 1164: The Business Case for Knowledge Management: A Guide provides state departments of transportation and other transportation agencies with practical tools to assess and measure the value of knowledge management (KM) initiatives. As experienced staff retire and collaboration across disciplines increases, agencies face growing challenges in preserving institutional knowledge and ensuring effective knowledge transfer. The guide outlines approaches for evaluating how KM practices contribute to improved business processes, workforce development, and organizational performance. It helps agencies articulate the return on investment of KM activities and integrate them into broader performance management strategies.

Accompanying the report, NCHRP Web-Only Document 437: Assessing and Measuring the Business Value of Knowledge Management documents the research effort and provides additional detail supporting the guide’s development.