Cooperative Research Programs Series
Periodicals and Other Documents
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Selection and Application of Manning’s Roughness Values in Two-Dimensional Hydraulic Models
3/20/2024 7:00:35 PM
Measures to improve the accuracy, reliability, and consistency in selecting roughness values for the application of 2D hydraulic models at highway crossings and in transportation corridors will represent a major step forward in the evolving state of practice. Whether a one-dimensional or a 2D modeling approach is taken, inconsistencies can exist from state to state, and even within states at the various district levels, on how to develop accurate and reliable hydraulic models. The fundamental issue is th...
Integrating Traffic Incident Management and Connected, Automated Technology Communities: A Guide for Communicating and Connecting
3/15/2024 7:00:02 PM
As vehicle technology advances, Traffic Incident Management (TIM) and emergency responders (ERs) are facing unprecedented circumstances in knowing how to engage with and respond to connected, automated vehicles (CAV). Uncertainty is complicated by limited communications and information exchanged between CAV developers, TIM, and ERs. NCHRP Research Report 1104: Integrating Traffic Incident Management and Connected, Automated Technology Communities: A Guide for Communicating and Connecting , from TRB's Nat...
The Effect of Vehicle Mix on Crash Frequency and Crash Severity
3/12/2024 1:00:21 PM
Crash prediction analysis focuses on identifying attributes that result in traffic crashes and proposes effective countermeasures to improve the roadway design and operational attributes. These crash frequency models are typically employed for examining crash counts either at the micro- (intersection or segment) or the macro-level (county or traffic analysis zone). NCHRP Research Report 1103: The Effect of Vehicle Mix on Crash Frequency and Crash Severity , from TRB's National Cooperative Highway Re...
Connected and Autonomous Vehicle Technology: Determining the Impact on State DOT Maintenance Programs
3/6/2024 5:00:30 PM
Traffic control devices, markings, signals, guardrail, computing systems, communications infrastructure, and other permanent and temporary devices will likely each be affected by the operation of connected and autonomous vehicle (CAV) technology. State departments of transportation (DOTs) need to identify gaps in knowledge and skills and prepare for the challenges of CAV implementation while maintaining the existing roadway system at an acceptable level of service. NCHRP Research Report 1084: Connected a...
Development of Clear Recovery Area Guidelines
2/23/2024 3:45:47 PM
The clear zone concept for roadside design emerged in the mid-1960s as a single distance for lateral clearance that reduced the likelihood of an errant vehicle striking a roadside obstacle. Subsequent recovery area guidance that evolved over the next two decades provided a variable distance expressed in terms of traffic volume, design speed, sideslope, and other roadway and roadside factors. NCHRP Research Report 1097: Development of Clear Recovery Area Guidelines , from TRB's National Cooperative Highwa...
Seismic Site Response Analysis with Pore Water Pressure Generation: Guidelines
2/16/2024 8:00:53 PM
One-dimensional (1D) equivalent-linear total-stress site response analysis (SRA) is the de facto standard for state department of transportation (DOT) highway facilities at locations where site-specific ground response analyses are conducted. However, many users and various DOTs have concerns about the applicability of equivalent-linear analyses for the cases where site-specific SRA is most relevant. NCHRP Research Report 1092: Seismic Site Response Analysis with Pore Water Pressure Generation: Guideline...
Guide for Intersection Control Evaluation
2/8/2024 3:00:09 PM
Intersection control evaluation (ICE) is fundamentally a process that provides the framework, steps, and tools and offers decision support for assessing trade-offs between different types of intersection forms and controls. NCHRP Research Report 1087: Guide for Intersection Control Evaluation , from TRB's National Cooperative Highway Research Program, defines intersection form as the physical layout of the intersection and intersection control as the traffic control device used to govern movements for ve...
Traffic Safety Culture Research Roadmap
2/5/2024 2:00:18 PM
As states and localities adopt a vision of zero traffic fatalities, greater attention is being given to communication, collaboration, leveraging resources, and applying a systemic approach to traffic safety which requires a change in culture among road users and traffic safety agencies. This change in culture is tied to education, engineering, enforcement, and emergency services. NCHRP Research Report 1091: Traffic Safety Culture Research Roadmap , from TRB's National Cooperative Highway Research Program...
Acceleration, Deceleration, and Stopping Sight Distance Criteria for Geometric Design of Highways and Streets
2/2/2024 3:00:39 PM
Acceleration, deceleration, and stopping sight distance (SSD) criteria are necessary considerations for determining geometric design requirements of roadways. Acceleration and deceleration are influenced by many factors, including grade, vehicle type, and maneuver type. Stopping sight distance is influenced by factors such as brake reaction time, object height, and driver’s eye height. NCHRP Research Report 1081: Acceleration, Deceleration, and Stopping Sight Distance Criteria for Geometric Design of Hig...
An Emergency Management Playbook for State Transportation Agencies
1/24/2024 6:02:53 PM
State departments of transportation and other state transportation organizations have many challenges in establishing and maintaining emergency management programs and plans that are proactive, responsive, flexible, and coordinated with the other local, tribal, state, regional, and federal agencies that may be involved in preparedness, mitigation, response and recovery. In addition, states vary in how they organize their emergency management activities. NCHRP Research Report 1093: An Emergency Management...
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