Cooperative Research Programs Series
Periodicals and Other Documents
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Subgrade Soil Susceptibility to Shrink/Swell and Frost Heave: Effects on Pavement Performance
4/12/2024 5:15:00 PM
Expansive clay soils that are susceptible to shrink and swell and silty soils that are susceptible to frost heave are found in many parts of the United States. At these locations, these soils serve as the subgrade of the pavement structure. NCHRP Research Report 1096: Subgrade Soil Susceptibility to Shrink/Swell and Frost Heave: Effects on Pavement Performance , from TRB's National Cooperative Highway Research Program, presents a state-of-the-art update to pavement design procedures to better reflect the...
MASH TL-3 Deflection Reduction for 31-Inch Guardrail: A Guide
4/9/2024 2:12:23 PM
Roadside obstacles are often too close to the roadway to permit the installation of common guardrail designs. Guardrail systems are often modified with a combination of tighter post spacing, nesting of rails, and other guardrail stiffening mechanisms to reduce deflections. NCHRP Research Report 1100: MASH TL-3 Deflection Reduction for 31-Inch Guardrail: A Guide , from TRB's National Cooperative Highway Research Program, presents a guide on the use of stiffening mechanisms to reduce the deflection for 31-...
Transformational Technologies and Mobility Inclusion Playbook
4/4/2024 7:00:14 PM
Changes in technology provide opportunities and risks to mobility, particularly as they relate to traditionally and newly underserved populations. In recent years, economic, environmental, and social forces have quickly given rise to shared and on-demand mobility—a collective of entrepreneurs and consumers leveraging technology to maximize transportation and financial resources and generate capital. For instance, shared mobility services have become part of a trend that has pushed shared, on-demand mobil...
Using Cooperative Automated Transportation Data for Freeway Operational Strategies
4/4/2024 6:00:21 PM
Since the introduction of digital computers more than 50 years ago, continuous developments in computer technology, emerging data sources, and communications have created opportunities for operational strategies and performance measures to improve freeway network safety and mobility. NCHRP Research Report 1080: Using Cooperative Automated Transportation Data for Freeway Operational Strategies , from TRB's National Cooperative Highway Research Program, is an assessment of transportation operational scenar...
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 1:00:01 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 5:58:11 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...
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