In search of the severity dimension of traffic events: Extended Delta-V as a traffic conflict indicator.
Most existing traffic conflict indicators do not sufficiently take into account the severity of the injuries resulting from a collision had it occurred. Thus far, most of the indicators that have been developed express the severity of a traffic encounter as their proximity to a collision in terms of time or space. This paper presents the theoretical framework and the first implementation of Extended Delta-V as a measure of traffic conflict severity in site-based observations. It is derived from the concept of Delta-V as it is applied in crash reconstructions, which refers to the change of velocity experienced by a road user during a crash. The concept of Delta-V is recognised as an important predictor of crash outcome severity. The paper explains how the measure is operationalised within the context of traffic conflict observations. The Extended Delta-V traffic conflict measure integrates the proximity to a crash as well as the outcome severity in the event a crash would have taken place, which are both important dimensions in defining the severity of a traffic event. The results from a case study are presented in which a number of traffic conflict indicators are calculated for interactions between left turning vehicles and vehicles driving straight through a signalised intersection. The results suggest that the Extended Delta-V indicator seems to perform well at selecting the most severe traffic events. The paper discusses how the indicator overcomes a number of limitations of traditional measures of conflict severity. While this is a promising first step towards operationalising an improved measure of traffic conflict severity, additional research is needed to further develop and validate the indicator.
Transport and Roads, Department of Technology and Society,Faculty of Engineering, LTH Lund University, Box 118,SE-22100 Lund, Sweden; Institute of Transport Economics, Gaustadalléen 21,NO-0349 Oslo, Norway. Electronic address: aliaksei.laureshyn@tft.lth.se.
Aliaksei
A
Laureshyn
Transport and Roads, Department of Technology and Society,Faculty of Engineering, LTH Lund University, Box 118,SE-22100 Lund, Sweden; Transportation Research Institute, Hasselt University, Wetenschapspark 5, bus 6,BE-3590 Diepenbeek, Belgium.
Tim
T
De Ceunynck
Transport and Roads, Department of Technology and Society,Faculty of Engineering, LTH Lund University, Box 118,SE-22100 Lund, Sweden.
Christoffer
C
Karlsson
Transport and Roads, Department of Technology and Society,Faculty of Engineering, LTH Lund University, Box 118,SE-22100 Lund, Sweden.
Åse
Å
Svensson
Transportation Research Institute, Hasselt University, Wetenschapspark 5, bus 6,BE-3590 Diepenbeek, Belgium.
Stijn
S
Daniels
D000063:Accidents, Traffic / Q000401:mortality / Q000706:statistics & numerical data*; D001334:Automobile Driving / Q000523:psychology*; D003220:Conflict, Psychological; D003654:Deceleration; D004779:Environment Design; D006801:Humans
Crash severity; Extended delta-V; Surrogate safety measures; Traffic conflicts; Traffic safety