| AADT | Average Annual Daily Traffic |
| ADHS | Appalachian Development Highway System |
| ADT | Average Daily Traffic |
| AASHTO | American Association of State Highway and Transportation Officials |
| BCR | Benefit-Cost Ratio |
| CMF | Crash Modification Factor |
| COG | Council of Governments |
| CRF | Crash Reduction Factor |
| D-CS | Detection-Control System |
| DOT | Department of Transportation |
| FHWA | Federal Highway Administration |
| FLMA | Federal Land Management Agency |
| FLTP | Federal Lands Transportation Program |
| FMCSA | Federal Motor Carrier Safety Administration |
| HAWK | High Intensity Activated Crosswalk |
| HRRR | High Risk Rural Roads |
| HRRRP | High Risk Rural Roads Program |
| HSIP | Highway Safety Improvement Program |
| HSM | Highway Safety Manual |
| HSP | Highway Safety Plan |
| ITS | Intelligent Transportation Systems |
| kph | kilometers per hour |
| LED | Light Emitting Diode |
| LTAP | Local Technical Assistance Program |
| MAP-21 | Moving Ahead for Progress in the 21st Century Act |
| mph | miles per hour |
| MPO | Metropolitan Planning Organization |
| MUTCD | Manual on Uniform Traffic Control Devices |
| NACE | National Association of County Engineers |
| NACO | National Association of Counties |
| NCHRP | National Cooperative Highway Research Program |
| NHI | National Highway Institute |
| NHPP | National Highway Performance Program |
| NHS | National Highway System |
| NHTSA | National Highway Transportation Safety Administration |
| RPC | Regional Planning Commission |
| RPO | Regional Planning Organization |
| RRFB | Rectangular Rapid Flash Beacon |
| RSA | Roadway Safety Audit |
| SAFETEA-LU | Safe, Accountable, Flexible Efficient Transportation Equity Act: A Legacy for Users |
| SHSP | Strategic Highway Safety Plan |
| SLOSSS | Suggested List of Surveillance Study Sites |
| SP&R | State Planning & Research |
| STIP | Statewide Transportation Improvement Program |
| STP | Surface Transportation Program |
| TAP | Transportation Alternatives Program |
| TIP | Transportation Improvement Program |
| TTAP | Tribal Technical Assistance Program |
| TTP | Tribal Transportation Program |
| TWLTL | Two-Way Left Turn Lane |
| USC | United States Code |
| USDOT | United States Department of Transportation |
| VMT | Vehicle Miles Traveled |
| vpd | vehicles per day |
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