Document Library

PIARC: Impact of the Development of Active Transport Modes in Road Tunnels – Current Situation Report and Case Studies examines the growing integration of active transportation modes—such as pedestrians, cyclists, and other vulnerable road users—within road tunnel environments. As cities seek to improve mobility, accessibility, and emissions outcomes, tunnel owners and operators face new safety, design, and operational challenges when authorizing active modes in these confined facilities. This international report compiles and evaluates case studies from around the world, highlighting how tunnels are being constructed or retrofitted to safely accommodate active users through infrastructure adaptations, equipment upgrades, and revised operational procedures.

The document categorizes examples into four approaches: tunnels with safety galleries usable by active modes, tunnels with protected spaces for active users, tunnels with specific geometric or operational adaptations, and tunnels dedicated entirely to active mobility. Drawing on global expert contributions, the report outlines the state of practice and identifies key considerations for safety, risk management, and coordination with emergency services. It provides a foundation for future recommendations to guide decision-making by tunnel owners, designers, safety professionals, and transportation agencies considering active mode integration.

The Texas Department of Transportation (TxDOT) spends hundreds of millions of dollars on utility relocations every year. Of the various situations in which a utility relocation is eligible for reimbursement, one of the most complex situations is when parts of the existing utility facility involve a property interest because the utility owner either has an easement or owns the property in fee simple. A wide range of practices exist for what constitutes eligibility for reimbursement.

The purpose of this research was to review and provide recommendations on the methodologies TxDOT uses to determine reimbursement eligibility and calculate utility reimbursement amounts. The research team conducted a review of national practices that included an analysis of relevant laws, regulations, and manuals, as well as interviews with state department of transportation officials. The research team conducted an analysis of a sample of utility agreements at TxDOT, including a review of reimbursement costs and reimbursement eligibility calculation methodologies, and prepared recommendations for implementation. The recommendations include strategies to consider for the calculation of eligibility ratios as well as strategies to improve the quality of utility agreements to make the review and approval process more consistent, accurate, and reliable.

Throughout its more than 25-year history, the Transit Capacity and Quality of Service Manual (TCQSM) has compiled the state of the practice based on peer-reviewed research published by the Transportation Research Board and others. The TCQSM provides transportation practitioners of varying levels of experience and responsibility information, techniques, and resources to support the planning, design, and operation of transit services, facilities, and systems. While the TCQSM’s methods represent the best available knowledge at the time of publication, they do not establish policies regarding desirable or appropriate levels of quality of service or capacity for transit services, facilities, or systems.

TCRP Research Report 262: Transit Capacity and Quality of Service Manual, 4th edition, includes updated statistics, transit agency application examples, and photographs. The manual incorporates emerging mobility options such as microtransit and low-speed automated vehicles, with expanded coverage of widely adopted technologies such as bus and ferry electrification. This edition updates key concepts related to modes and services, operations, and quality of service. Additional updates address topics including quality of service measures and applications, bus transit, demand-responsive transit, rail transit, ferry transit, and transit stops and stations.

This conduct of Research Report for NCHRP Project 20-44(40) was submitted July 2025. It accompanies the Transportation Agency Capability Building Web-Based Guide in order to support implementation efforts and build upon the framework established in NCHRP 20-24(95) and facilitate the use of ACB guidance by transportation agencies. Practitioners may also find the Performance Management Reporting Peer Exchange Final Report – NCHRP Project 20-24 Task 124 (2019) of interest as well.

The Using Performance Management to Respond to Uncertainty Peer Exchange was a collaborative forum designed to facilitate the sharing of noteworthy practices and lessons learned in applying transportation performance management (TPM) approaches to manage unexpected disruptions and changes. The peer exchange brought together State DOTs, FHWA, and other transportation agencies to discuss the latest strategies, tools, and resources for improving transportation agency adaptation. The peer exchange aimed to apply and advance TPM practice to help agencies respond to uncertainty, foster a collaborative environment to improve outcomes using performance management, and engage in peer-to-peer problem-solving, sharing noteworthy TPM practices, and exploring innovative solutions to enhance transportation agency adaptability in the face of uncertainty. This summary details the content, discussions, and resources shared during the peer exchange.

The 15th National TAM Conference on Transportation Asset Management was held Aug 25-28 in Chicago, IL, USA. Materials from the conference sessions are linked in the attached conference program in the "Schedule At-A-Glance" section. For more information on individual sessions, please refer to the detailed agenda on the conference site.

This report summarizes the findings and recommendations from dozens of after-action reviews conducted over an 18-month period, focusing on interstate work zones and maintenance of traffic (MOT) procedures. The underlying reports compile data including project locations, visual imagery, connected vehicle summary graphics, and qualitative discussions to evaluate work zone efficacy. By synthesizing these reviews, the document identifies systemic challenges in the intersection of traffic control design and field execution, offering actionable insights to improve safety, communication, and traffic flow.

The document details six primary themes and recommendations aimed at improving future MOT planning. It addresses geometric inaccuracies in design plans—such as failing to account for constraints like bridges and guardrails—and suggests using LiDAR surveys to achieve more precise dimensions. Additionally, it highlights the need for smoother vehicle transitions during lane shifts, better communication between design engineers and temporary traffic control contractors, and structured project close-out reviews to document lessons learned. Finally, the document provides tactical recommendations for managing traffic capacity, calling for standardized guidelines for rolling slowdowns within the Indiana Department of Transportation's oversight and stricter scheduling for barrier wall deployment to mitigate severe traffic queuing.

NCHRP Web-Only Document 432: Impacts and Performance of State DOT Resilience Efforts, from TRB's National Cooperative Highway Research Program, supplements NCHRP Research Report 1159 by providing detailed methods, tools, and case examples for evaluating transportation system resilience. The document supports state DOTs in developing performance-based approaches to assess and improve the effectiveness of resilience initiatives and investments.

State departments of transportation are increasingly prioritizing resilience to address disruptions from extreme weather, economic shifts, and population changes. NCHRP Research Report 1159: Measuring Impacts and Performance of State DOT Resilience Efforts* provides guidance on using resilience performance measures to evaluate and justify investments in transportation system resilience. Supplemental NCHRP Web-Only Document 432: Impacts and Performance of State DOT Resilience Efforts provides additional resources for state DOTs in developing performance-based approaches to assess and improve the effectiveness of resilience initiatives and investments.

The Safe System Approach (SSA) is a comprehensive framework that emphasizes shared responsibility, proactive design to accommodate human error, and the management of kinetic energy to prevent serious injuries and fatalities among roadway users. The SSA offers the potential for broader safety impacts than siloed or isolated safety efforts.

NCHRP Web-Only Document 451: Developing a Toolkit to Institutionalize the Safe System Approach documents the research effort underlying the development of NCHRP Research Report 1181: Toolkit for Institutionalizing the Safe System Approach.

NCHRP Research Report 1181: Toolkit for Institutionalizing the Safe System Approach, presents 30 tools designed to support the broader institutionalization of the SSA. These tools assist transportation agencies in assessing, refining, and aligning their systems, funding strategies, decision-making processes, and project delivery practices with Safe System principles. The report provides practical, proven, and emerging strategies to support meaningful implementation across departments and levels of government. It also serves as a valuable companion to existing SSA guidance by offering hands-on tools and real-world examples that help address common institutional challenges and support sustained safety outcomes within a transformed safety culture.

Artificial intelligence—especially machine learning—is rapidly entering safety-critical domains where failures can harm people, the environment, or property. This report examines how to integrate ML safely into physical systems and outlines research priorities for safety, testing, and evaluation. It argues that rigorous safety-engineering practices must be adapted to ML, requiring changes in research, training, and engineering workflows. The authors urge a shift from judging algorithms by accuracy alone to ensuring system-level safety and reliability.