U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
Ranges for Design Speed | |
Relative Risk of Differential Speed Caused by Changes in Roadway Geometry | |
Ranges for Lane Width | |
Operational Effects of Freeway Lane Widths | |
Operational Effects of Lane and Shoulder Width on Two-Lane Highways | |
Lane Width: Potential Adverse Impacts to Safety and Operations | |
Ranges for Minimum Shoulder Width | |
Operational Effects of Freeway Shoulder Widths | |
Shoulder Width: Potential Adverse Impacts to Safety and Operations | |
Bridge Width: Potential Adverse Impacts to Safety and Operations | |
Horizontal Alignment: Potential Adverse Impacts to Safety and Operations | |
Accident Modification Factors for Superelevation on Rural Two-Lane Highways | |
Superelevation: Potential Adverse Impacts to Safety and Operations | |
Accident Modification Factors for Grade on Rural Two-Lane Highways | |
Grade: Potential Adverse Impacts to Safety and Operations | |
Relative Safety Risk of Various Conditions in Combination with Non-Standard Stopping Sight Distance | |
Stopping Sight Distance: Potential Adverse Impacts to Safety and Operations | |
Cross Slope: Potential Adverse Impacts to Safety and Operations | |
Ranges for Minimum Vertical Clearance | |
Vertical Clearance: Potential Adverse Impacts to Safety and Operations | |
Lateral Offset to Obstruction: Potential Adverse Impacts to Safety and Operations | |
Potential Mitigation Strategies | |
Combinations of Lane and Shoulder Width Considered | |
Types of Before-and-After Data Collected |