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                Media ContactsMenu OFFICE OF RESEARCH, DEVELOPMENT, AND TECHNOLOGY AT THE TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Home
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   Ana Maria Eigen
      Ana Maria Eigen
      
                    
            Research Highway Safety Specialist
      
                    
            Office of Safety and Operations Research and Development
      
                    
            Turner-Fairbank Highway Research Center6300 Georgetown PikeMcLean, VA 22101United States
      
          
    **Email:**ana.eigen@dot.gov**Phone:** (202) 493-3168
    If you are deaf, hard of hearing, or have a speech disability, please dial 7-1-1 to access telecommunications relay services.
                
                Technical Summaries
    

    
    
    
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Research reports are often summarized in executive summaries, technical briefs, or other abbreviated formats. Included here are those road safety summaries that involved research using HSIS data.

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**Safety Effects of Horizontal Curve and Grade Combinations on Rural Two-Lane Highways**

The safety effects of horizontal curves and grades on rural two-lane highways have been quantified in the American Association of State Highway and Transportation Officials (AASHTO) Highway Safety Manual (HSM), but it was not previously known whether and how the safety performance of horizontal curves and grades interact. Furthermore, there are no established safety effects for crest and sag vertical curves, and it is unknown whether and how the safety performance of crest or sag vertical curves is affected by the presence of horizontal curves.

The objective of this study was to quantify the combined safety effects of horizontal curves and grade combinations and express the results as crash modification factors (CMFs) that can be considered for use in the AASHTO HSM.

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HRTM2130_Calculator-tool.xlsm (2.04 MB)


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**Safety Evaluation of Converting Traffic Signals from Incandescent to Light-Emitting Diodes**

Across the Nation, many agencies have been replacing conventional incandescent light bulbs in traffic signals with light-emitting diodes (LED). LEDs are primarily installed to reduce energy consumption and decrease maintenance. In addition, LEDs are expected to last much longer compared with incandescent bulbs and tend to age gradually. However, a recent study revealed several potential problems with LEDs, including their inability to melt snow and issues related to visual discomfort caused by glare at night.

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**Safety Evaluation Of Discontinuing Late-Night Flash Operations at Signalized Intersections**

During late-night flash (LNF) mode (from late night to early morning hours), traffic signals flash yellow for one road (typically, the major road), requiring caution but no stopping, and flash red for the other road (typically, the minor road), requiring drivers to stop and then proceed through the intersection after yielding to the traffic on the major road. The intent of LNF is to reduce energy consumption and delay during periods of low traffic demand. However, in recent years, many agencies have begun replacing LNF with normal phasing operation because of safety concerns.

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            Expand All
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        **2009**
        Title
			Pub Date
			Author
			Report NumberSafety Evaluation of Lane and Shoulder Width Combinations on Rural, Two-Lane, Undivided Roads
			May
			FHWA
			FHWA-HRT-09-032
  


      **2008**
        Title
			Pub Date
			Author
			Report NumberTwo Low-Cost Safety Concepts for Two-Way STOP-Controlled, Rural Intersections on High-Speed Two-Lane
			September
			Hughes, W., R. Jagannathan, and F. Gross
			FHWA-HRT-08-063NCHRP Research Results Digest 329: Highway Safety Manual Data Needs Guide
			June
			NCHRPSafety Evaluation of Center Two-Way Left-Turn Lanes on Two-Lane Roads
			March
			FHWA
			FHWA-HRT-08-046Safety Evaluation of Flashing Beacons at Stop-Controlled Intersections
			March
			FHWA
			FHWA-HRT-08-048Safety Evaluation of STOP AHEAD Pavement Markings
			March
			FHWA
			FHWA-HRT-08-045
  


      **2007**
        Title
			Pub Date
			Author
			Report NumberNCHRP Research Results Digest 318: An Expert System for Recommending Speed Limits in Speed Zones
			
			May
			NCHRP
  


      **2005**
        Title
			Pub Date
			Author
			Report NumberNCHRP Research Results Digest 299: Crash Reduction Factors for Traffic Engineering and Intelligent Transportation System
			November
			NCHRP

    
          Last updated: Tuesday, July 18, 2023 U.S. DEPARTMENT OF TRANSPORTATION

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