The authors of this report greatly appreciate the time, information, insights, and access provided by representatives of the following public agencies:
- District of Columbia Department of Transportation
- Texas Department of Transportation
- Michigan Department of Transportation
- Arkansas State Highway and Transportation Department
- North Carolina Department of Transportation.
The authors also greatly appreciate the cooperation and assistance with data collection and archiving as provided by the following vendors:
- ASTI Transportation Systems Incorporated
- Give 'Em A Break Safety
- International Road Dynamics
- Protection Services Incorporated
- Scientex Corporation
- United Rentals Highway Technologies.