1. Reduced Datasets from Roadway Information Database (RID)
U.S. Department of Transportation
Federal Highway Administration
Office of Safety Research and Development
Reduced Datasets from Roadway Information Database (RID)
Yusuf Mohamedshah
Traffic Records Forum
August 04, 2019
Source: FHWA

2. OUTLINE
Brief description of Second Strategic Highway Research Program (SHRP2) Naturalistic Driving Study (NDS) and RID.
New Reduced Datasets:
Annual Average Daily Traffic (AADT).
Intersection Width.
Intersection Crashes.
Curve Crashes.
Homogeneous Segments.
Future Enhancements:
Reduced Datasets.
All Road Network of Linear Referenced Data (ARNOLD) as RID Linear Referencing System (LRS).

3. RID NDS SHRP2 Safety Data (GIS) Data Complete Captured System
Naturalistic Driving Study
Roadway Information Data
Geographic Information Systems (GIS)
Source: FHWA

4. 5.4 Million trips – 30+ million miles Passenger car, Van, SUV, Pickup
NDS Data
3,500 Participants
5.4 Million trips – 30+ million miles
Passenger car, Van, SUV, Pickup
1,400+ crashes
1 Million hours of continuously recorded video (exposure data)
Physical Size: 4 petabytes of data
Source: FHWA

5. RID Provides context to the NDS data. Contains four types of data:
Mobile van-collected data.
Acquired data from each site.
Existing data from State DOTs and ESRI.
Highway Performance Monitoring System (HPMS) data.

6. Mobile Van Data Collection Sites
Data collected from six States:
Florida (Tampa).
Indiana (Bloomington).
Pennsylvania (State College).
New York (Buffalo).
North Carolina (Durham).
Washington (Seattle).
Approximately 25,000 centerline miles of data collected.

7. Mobile Van Collected Assets
33,000 miles of shoulders
518,570 signs
11,852 miles of rumble
10,756 miles of median
7,376 miles of lighting
6,129 miles of barriers
43,195 intersections
Source: FHWA

8. Reduced Datasets Can be used off-the-shelf.
Does not need expert GIS skills.
Addresses highway safety research questions.
Is available with full copy of RID.
Provides step-by-step documentation.
Supplies a user guide.

9. AADT Description: Data used: Usage:
Single separate layer for each State.
AADT values by year in a single record.
Data used:
State-provided traffic data.
Multiple values for same year.
HPMS data.
Usage:
Crash prediction models.
Development of Safety Performance Functions (SPFs).
Development of Severity Distribution Functions (SDFs).

10. Intersection Width Description: Data used: Usage:
Calculated width of intersection.
Location of median openings and driveways.
Data used:
Divided/Undivided Reduced Dataset.
Lane-Reduced Dataset.
Usage:
Safety performance of intersections.
Design of yellow and red signal times.
Safety of vulnerable road users crossing intersections.

11. Intersection Crashes Description: Data Used: Usage:
Summary of intersection and intersection-related crashes.
Summary of crashes by year.
Ability for users to define their own buffer distance.
Data Used:
Crash history files provided by each State.
Intersection Reduced Dataset.
Usage:
Safety performance impacts of various intersection features.
Cross-sectional analysis.

12. Curve Crashes Description: Data Used: Usage:
Summary of curve crashes attached to individual curves in curve-reduced dataset.
Curve variables attached to each curve crash.
A relational table.
Data Used:
Curve crashes from historic crashes collected from States.
Reduced Curve Database.
Usage:
Safety performance impacts of various features of horizontal curves.
Cross-sectional analysis.

13. Homogeneous Segments Description: Data used: Usage:
Homogeneous segments based on various features from mobile-collected data.
Data used:
Alignment.
Lane-Reduced Dataset.
Rumble Strips.
Usage:
Cross-sectional analysis.
Comparison of similar sites.
Summary of roadway characteristics.

14. Planned Reduced Datasets
Five additional reduced datasets:
Roadway Attributes for All Crashes.
Comprehensive LRS (merged States).
Link-based Crash Experience.
Update Link Road Attributes.
Relating Opposite Direction on Divided Highways.
ARNOLD as RID LRS.

15. More Information Contact:
Safety Training and Analysis Center (STAC) website: