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                Media ContactsMenu OFFICE OF RESEARCH, DEVELOPMENT, AND TECHNOLOGY AT THE TURNER-FAIRBANK HIGHWAY RESEARCH CENTER Home
                        Research


            
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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.
                
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HSIS data are sometimes used in research studies that result in other types of finished products, such as dissertations, theses, and conference proceedings.

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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.

Download PDF versionView HTML version

HRTM2130_Calculator-tool.xlsm (2.04 MB)


Highlight Products

**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
      Collapse All
        **2021**
        Title
			Publication Date
			AuthorDevelopment of Safety Performance Functions for Two-Lane Rural Highways in The State of Ohio
			January
			Abdulrahman Faden and Deogratias Eustace
  


      **2020**
        Title
			Publication Date
			AuthorThe Safety Impact of Raising Speed Limit on Rural Freeways In Ohio
			January
			Oluwaseun Olufowobi
  


      **2018**
        Title
			Publication Date
			AuthorPassenger Vehicle-Motorcycle Pre-Crash Trajectory Reconstruction Results Based on an Extended Application of the NHTSA-Honda-DRI ACAT Safety Impact Methodology
			January
			R Michael Van Auken, John Lenkeit, and Terry SmithRisk Factors Affecting Crash Injury Severity by Work Zone Area
			January
			Krupanidhi Koilada, Srinivas S Pulugurtha, and Ajinkya S Mane
  


      **2017**
        Title
			Publication Date
			AuthorEvaluating the Interactive Effects of Traffic Volumes and Access Density on Crash Frequency
			January
			Ali Mohammed Alsubeai
  


      **2016**
        Title
			Publication Date
			AuthorIntersection Lighting Impacts on Nighttime Crashes Reduction and Safety Improvement
			January
			Mohammed Said Obeidat and Malgorzata J Rys
  


      **2015**
        Title
			Publication Date
			AuthorModeling of Guide Sign Illumination and Retroreflectivity to Improve Driver’s Visibility and Safety
			January
			Mohammed ObeidatThe Impacts of Illumination on Nighttime Safety at Roundabouts
			January
			Franklin E GbologahNighttime Safety and Pavement Marking Retroreflectivity on Two-Lane Highways: Revisited with North Carolina Data
			January
			Paul J Carlson, Raul Avelar, Eun Sug Park, and Don Kang
  


      **2011**
        Title
			Publication Date
			AuthorInfluence of Seasonal Temperature on Pavement Reliability Performance: A Case Study
			May
			Roya Amjadi, Jim Sherwood, and Gerardo FlintschAnalysis of Factors Affecting Traffic Accident Severity Based on Heteroskedasticity Ordinal Logit
			May
			Zhangcun Yan, Xiaozhao Lu, and Wanxin HuA Framework for Developing Road Risk Indices Using Quantile Regression Based Crash Prediction Model
			January
			Hui WuReliability-Based Safety Evaluation of Traffic on Rural Highway
			January
			Feng Chen
  


      **2010**
        Title
			Publication Date
			AuthorSafety Evaluation of Transverse Rumble Strips on Approaches to Stop Controlled Intersections in Rural
			January
			Srinivasan, R., Baek, J., and Council, F.
  


      **2009**
        Title
			Publication Date
			AuthorA Methodology to Explore the Relationship Between Pavement Marking Retroreflectivity and Traffic Crash
			January
			Donnell, E., V. Karwa, and S. SathyanarayananCollision Prediction Models for Three-Dimensional Two-Lane Highways: I. Horizontal Curves
			January
			Easa, S. and Q. YouCollision Prediction Models for Three-Dimensional Two-Lane Highways: II. Horizontal Tangents
			January
			Easa, S. and Q. YouApplication of Bayesian Statistics to Identify Highway Sections with Atypically High Rates of Median
			January
			Davis, G., H. Xiong, and H. TaoThe Benefits of Pavement Markings: A Renewed Perspective Based on Recent and Ongoing Research
			January
			Carlson, P.J., E.S. Park, and C.K. Anderson
  


      **2008**
        Title
			Publication Date
			AuthorNo-Fault Insurance and Automobile Accidents
			October
			Heaton, P. and E. HellandEvaluation of Alternative Hyper-priors for Bayesian Road Safety Analysis
			January
			Miranda-Moreno, L.F., D. Lord, andDevelopment of a Web-Based Expert System for Setting Speed Limits in Speed Zones
			January
			Srinivasan, R., D.L. Harkey, D. Tharpe, R. Sumner, and M.R. ParkerOptimization of Network Safety Improvements Using Empirical Bayes Analysis for Models with Accident
			January
			Banihashemi, M.Exploratory Analysis of Relationship between the Number of Lanes and Safety on Urban Freeways
			January
			Kononov, J., B. Bailey, and B.K. AlleryWork Zone Safety and Mobility Issues: Case Study on Dan Ryan Reconstruction Project
			January
			Shi, J.Use of Single Vehicle Collisions to Model Fatigue-Related Crashes on Rural Two-Lane Highways
			January
			Xu Lin
  


      **2007**
        Title
			Publication Date
			AuthorDetermining the Extent and Characteristics of Overrepresentation of Large Truck Crashes in Daytime a
			December
			Mokkapati, N.Weather-Related Crashes on Public Land
			August
			Moore, L.Risk Factors for Trucks on Freeways
			August
			Amjadi, R., J. Fife, C. Tan, and G. DavisIdentification of High Car-Truck Crash Corridors on North Carolina Interstate Roadways
			March
			Council, F.M., R. Srinivasan, and B. HejaziSafety Assessment of the Interchange Spacing on Urban Freeways: Enhanced Models
			January
			Pilko, P., J.G. Bared, P.K. Edara, and T. KimAppraisal of the Interactive Highway Safety Design Model's Crash Prediction and Design Consistency
			January
			Donnell, E.T., B.P. Stodart, and F. GrossEB Analysis in the Micro Optimization of the Improvement Benefits of Highway Segments for Models
			January
			Banihashemi, M.Safety Assessment of Interchange Spacing on Urban Freeways: Enhanced Models
			January
			Pilko, P., J.G. Bared, P.K. Edara, and T. KimEstimating the Variance in Before-After Studies
			January
			Ye, Z. and D. LordBayesian Multivariate Poisson-Lognormal Regression for Crash Prediction on Rural Two-Lane Highways
			January
			Ma, J., K.M. Kockelman, and P. DamienFactors Contributing to Pedestrian and Bicycle Crashes on Rural Highways
			January
			Carter, D.L. and F.M. Council
  


      **2006**
        Title
			Publication Date
			AuthorSafety Impacts of Interchange Spacing on Urban Freeways
			January
			Bared, J.G., P. Edara, and T. KimSafety Impacts of Differential and Uniform Car-Truck Speed Limits on Illinois and North Carolina Int
			JanuaryIdentifying Secondary Crash Characteristics for California Highway System
			January
			Hirunyanitiwattana, W. and S. MattinglyNumerical Examination of Freeway Rear-End Accidents Considering Mechanism of Accident Occurrence
			January
			Kim, J.K., G. Ulfarsson, and Y. Wang
  


      **2004**
        Title
			Publication Date
			AuthorFreeway Speeds and Speed Variations Preceding Crashes, Within and Across Lanes
			January
			Kockelman, K.M. and J. MaAnticipating Injury & Death: controlling for New Variables on Southern California Highways
			January
			Ma, J. and K.M. KockelmanEvaluation of the Effectiveness of Shoulder Rumble Strips on Rural Multi-lane Divided Highways in Minnesota
			January
			Carrasco, O., J. McFadden, and P. ChandhokSafety of U-Turns at Unsignalized Median Openings on Urban and Suburban Arterials
			January
			Potts, I.B., D.W. Harwood, H.S. Levinson, and J. Gluck
  


      **2001**
        Title
			Publication Date
			AuthorGIS Safety Analysis Tools, Version 3.0
			January
  


      **1992**
        Title
			Publication Date
			AuthorInvestigation of Appropriate Objects Stopping Sight Distance
			December
			Karen B. Kahl
  


      **1991**
        Title
			Publication Date
			AuthorCorrelation of Truck Accidents with Highway Geometry
			January
			Mohamedshah, Yusaf M
  


      **Publication Year Unknown**
        Title
			Publication Date
			AuthorThe Application of an Improved Highway Safety Evaluation
			
			Jun WangSafety Evaluation of Continues Shoulder Rumble Strips Installed on Freeways
			
			Michael S. GriffithThe Effects of Freeway Management Systems and Motorist Assistance Patrols on the Frequency of Report
			
			Todd OlmsteadThe Effect of Infrastructure and Demographic Change on Traffic-related Fatalities and Crashes: A Ca
			
			Robert B. Noland, and Lyoong Oh

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

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