Vision Zero is a multi-faceted road safety framework that aims to eliminate all traffic-induced fatalities and lifelong injuries. One aspect of achieving Vision Zero is choosing roadway speeds that do not exceed the biomechanical limits of crash-involved road users. Previous work has attempted to use speed-based metrics, such as the last recorded travel speed, to build injury risk prediction models to help inform safe speed selection. However, these metrics can be somewhat unreliable severity metrics in some crash modes and with some collision partners. Maximum delta-v (change in vehicle velocity during the crash) is a well-known indicator of crash severity but lacks a robust relationship to posted speed limits. The objective of this study was to quantify the relationship between posted speed limits and crash-involved road user injury risk based on maximum delta-v. Worst-case crash scenarios were developed for seven crash types to compute maximum delta-v. These maximum delta-v values were then applied to previously developed frontal, oblique, or rear crash injury risk prediction models. The injury risk values were parsed by crash type distributions to determine the total annual number of moderate to fatal injuries for a given roadway type and posted speed limit. These annual injury totals were then divided by the actual annual number of crashes to obtain injury-to-crash ratios, also known as injury modification factors. The result of this study was a tool that can inform posted speed limit selection by comparing safety benefits among various posted speed limit and roadway type combinations.
World Health Organization. Global Status Report on Road Safety 2018: Summary. WHO/NMH/NVI/18.20. World Health Organization, Geneva, 2018.
2.
National Center for Statistics and Analysis. Traffic Safety Facts 2020: A Compilation of Motor Vehicle Crash Data. National Highway Traffic Safety Administration, Washington, D.C., 2022.
BelinM.-A.JohanssonR.LindbergJ.TingvallC.The Vision Zero and Its Consequences. Proc., 4h International Conference on Safety and the Environment in the 21st Century, Tel Aviv, Israel, November 23–27, 1997.
7.
LarssonP.TingvallC.The Safe System Approach – A Road Safety Strategy Based on Human Factors Principles. In Engineering Psychology and Cognitive Ergonomics. Applications and Services (HarrisD., ed.), Lecture Notes in Computer Science, Vol. 8020, Springer Berlin Heidelberg, 2013, pp. 19–28. https://doi.org/10.1007/978-3-642-39354-9_3.
National Highway Traffic Safety Administration, Federal Highway Administration, and U.S. Department of Transportation. The Effect of Increased Speed Limits in the Post-NMSL Era. National Highway Traffic Safety Administration, Washington, D.C., February1998.
AminK.HedlundJ.ForsmanÅ.VadebyA.FredrikssonRikardHurtigP.LarssonP.LindholmM.RizziM.SternlundS.Analysis of Road Safety Trends 2020. No. 2021:173. The Swedish Transport Administration, 2021, p. 96.
15.
Early Estimates of Motor Vehicle Traffic Fatalities and Fatality Rate by Sub-Categories in 2021. National Center for Statistics and Analysis, NHTSA, Washington, D.C., 2022.
16.
Early Estimate of Motor Vehicle Traffic Fatalities for the First 9 Months (January–September) of 2022. National Center for Statistics and Analysis, NHTSA, Washington, D.C., 2022.
DoeckeS. D.BaldockM. R. J.KloedenC. N.DutschkeJ. K.Impact Speed and the Risk of Serious Injury in Vehicle Crashes. Accident Analysis & Prevention, Vol. 144, 2020, p. 105629. https://doi.org/10.1016/j.aap.2020.105629.
25.
JurewiczC.SobhaniA.WoolleyJ.DutschkeJ. K.CorbenB.Exploration of Vehicle Impact Speed–Injury Severity Relationships for Application in Safer Road Design. Proc., 6th Transport Research Arena, Warsaw, Poland, April 18–21, 2016.
26.
EugenssonA.IvarssonJ.LieA.TingvallC.Cars Are Driven on Roads, Joint Visions and Modern Technologies Stress the Need for Co-Operation. Proc., 22nd Enhanced Safety of Vehicles Conference, Washington, D.C., June 13–16, 2011.
27.
StigsonH.KullgrenA.RosénE.Injury Risk Functions in Frontal Impacts Using Data from Crash Pulse Recorders. Annals of Advances in Automotive Medicine/Annual Scientific Conference, Vol. 56, 2012, pp. 267–276.
28.
DoeckeS. D.KloedenC. N.DutschkeJ. K.BaldockM. R. J.Safe Speed Limits for a Safe System: The Relationship Between Speed Limit and Fatal Crash Rate for Different Crash Types. Traffic Injury Prevention, Vol. 19, No. 4, 2018, pp. 404–408. https://doi.org/10.1080/15389588.2017.1422601.
29.
WramborgP.A New Approach to a Safe and Sustainable Road Structure and Street Design for Urban Areas. Presented at the Road Safety on Four Continents: 13th International Conference Swedish National Road and Transport Research Institute (VTI) Ministry of Infrastructure, Poland Global Road Safety Partnership Forum of European Road Safety Research Institutes European Conference of Transport Research Institutes Transportation Research Board Council for Scientific and Industrial Research National Road Safety Council, Poland, October 2005. https://trid.trb.org/view/851729.
30.
DeanM. E.LubbeN.FredrikssonR.SternlundS.GablerH. C.Assessing the Applicability of Impact Speed Injury Risk Curves Based on US Data to Defining Safe Speeds in the US and Sweden. Accident Analysis & Prevention, Vol. 190, 2023, p. 107151.
31.
KusanoK. D.GablerH. C.Comprehensive Target Populations for Current Active Safety Systems Using National Crash Databases. Traffic Injury Prevention, Vol. 15, No. 7, 2014, pp. 753–761. https://doi.org/10.1080/15389588.2013.871003.
32.
BurdettB.LiZ.BillA. R.NoyceD. A.Accuracy of Injury Severity Ratings on Police Crash Reports. Transportation Research Record: Journal of the Transportation Research Board, 2015. 2516: 58–67.
National Highway Traffic Safety Administration. Comparing Demographic Trends in Vulnerable Road User Fatalities and the U.S. Population, 1980–2019. DOT HS 813 178. National Center for Statistics and Analysis, NHTSA, Washington, D.C., August2021.
35.
ISO 12352-2 Road Vehicles - Traffic Accident Analysis - Guidelines for the Use of Impact Severity Measures. International Standards Organization, 2003. https://www.iso.org/standard/25945.html.
36.
GablerH. C.HamptonC.RostonT. A.Estimating Crash Severity: Can Event Data Recorders Replace Crash Reconstruction?Proceedings: International Technical Conference on the Enhanced Safety of Vehicles, Vol. 2003, 2003, p. 12.
37.
TatemW. M.The Crash Injury Risk to Rear Seated Passenger Vehicle Occupants. Virginia Tech, Blacksburg.
TingvallC.IfverJ.KrafftM.KullgrenA.LieA.RizziM.SternlundS.StigsonH.StrandrothJ.The Consequences of Adopting a MAIS 3 Injury Target for Road Safety in the EU: A Comparison with Targets Based on Fatalities and Long-term Consequences. Proc., IRCOBI Conference, Sweden, 2013.
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