Automation allows for continuous operations monitoring with high-resolution data rather than relying on periodic manual reviews. New publications from TRB's National Cooperative Highway Research Program give you the tools you need to interpret the data from automated traffic signal performance measures to manage your systems and connect operational insights to safety outcomes. 

NCHRP Research Report 1170: Evaluating the Safety Effects of Automated Traffic Signal Performance Measures presents two methods to quantify changes in crash frequency and severity as well as develop crash modification factors.

NCHRP Web-Only Document 442: Crash Modification Factors for Automated Traffic Signal Performance Measures provides factors that quantify the potential safety effects of addressing issues such as split failures, inefficient signal timing, or vehicles arriving during red intervals. These allow you to estimate expected crash reductions and determine signal performance improvements to incorporate.

NCHRP Synthesis 659: Automated Traffic Signal Performance Measures: Management, Operation, and Maintenance documents how some agencies are implementing and sustaining their programs. 

When drivers drift toward the edge of the roadway on curves or around other obstacles, guardrails, barriers, and other roadside hardware make highways safer. They work best when drivers can clearly see them in time to react. TRB's NCHRP Research Report 1141: Delineation of Linear Roadside Hardware Systems and Roadside Obstacles combines crash data analysis with a human factors study to show how drivers perceive and respond to roadside barriers and obstacles, particularly in dry daytime and nighttime conditions.

Notably successful treatments include post-mounted delineators on guardrail systems and continuous retroreflective paint stripe on concrete barriers. Markers placed in front of a culvert also improved drivers' detection of a roadside obstacle. In addition to these findings, the project provided drafted updates for the Federal Highway Administration's Manual on Uniform Traffic Control Devices as well as American Association of State Highway and Transportation Officials' Roadside Design Guide and the Policy on Geometric Design of Highways and Streets.

July 12 - 15 - Register to attend TRB's 65th annual Workshop on Transportation Law in Irvine, CA