IAP Project: Concept to Countermeasure- Research to Deployment Using the 2nd Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) Data: The Interrelationships between Speed Limits’ Geometry and Driver Behavior

Project Description This research study was sponsored by Federal Highway Administration Implementation Assistance Program with funds flowing through the Michigan Department of Transportation. This study proposed to examine the rates of crash and near-crash events along freeway segments with various statutory speed limits. In addition to examining the naturalistic driving study (NDS) event data, additional support data will be obtained from the roadway information database (RID). Additionally, speed data will also be compared for select drivers over common freeway segments. The metrics to examine as a part of this effort will include the mean speed and speed variance for the same driver over various trips on the same segment, as well as for different drivers on these same segments. Data Request Scope The dataset delivered consisted of a sample of detailed event tables (including trip summaries, vehicle, and driver survey results) and time series variables collected for multiple drivers as part of the SHRP2 Naturalistic Driving Study. Time-series data (de-identified) was requested approximately for 300 near-crashes and 3700 baseline events. In particular, identified features of road geometry and driver behavior-related factors contributing to speed-related crashes/near crashes using data available from the InSight website were used to select relevant events (crashes, near-crashes, or baselines) on roads segments with “locality” type of “interstate/bypass/divided highway with no traffic signals” features. Data Specification The time series data included: vehicle trajectory data (e.g. latitude, longitude, speed, acceleration, and velocity) and vehicle control data (e.g., pedal gas position, pedal brake state steering wheel position). Additionally, a shape file of the travel density maps similar to those shown on the InSight website for all six states (FL, IN, NY, NC, PA, WA) including a layer with the number of trips and the number of drivers traversing each Link ID were added as well.