“I did not see that coming”: A latent variable structural equation model for understanding the effect of road predictability on crashes along horizontal curves

“I did not see that coming”: A latent variable structural equation model for understanding the effect of road predictability on crashes along horizontal curves

Afghari, A.P. (TU Delft Safety and Security Science)
Vos, J. (TU Delft Transport and Planning)
Farah, H. (TU Delft Transport and Planning)
Papadimitriou, E. (TU Delft Safety and Security Science)

2023

Driver anticipation plays a crucial role in crashes along horizontal curves. Anticipation is related to road predictability and can be influenced by roadway geometric design. Therefore, it is essential to understand which geometric design elements can influence anticipation and cause the road to be (un)predictable. This exercise, however, is not straightforward because anticipation is individual-specific whereas road geometric design is location-specific; anticipation is latent and measuring it may not be trivial; anticipation may have several stages from the preceding tangent until the midst of the curve; and not all drivers anticipate in the same way and thus there may well be unobserved heterogeneity in the effect of anticipation on crash risk. Despite methodological advancements in crash risk modelling, there is no econometric model that can adequately explain the above complexities. This study aims to fill this gap by developing an econometric model with a new latent variable, named ‘predictability’ that is measured by individual-specific driving behaviour indicators and predicted by location-specific road geometric factors. The model is specified with random parameters to account for unobserved heterogeneity and is empirically tested by a unique dataset including detailed geometric design and driver behaviour data obtained for 156 curves in the Netherlands. Results indicate that higher exposure and uphill vertical grade are associated with increased likelihood of vehicle crashes along horizontal curves, whereas adequate superelevation and higher predictability are associated with decreased likelihood of those crashes. Pavement friction influences this likelihood too but it has varied effects. Road predictability is influenced by the differences in angle of horizontal curves, vertical grades, and width of consecutive road segments.

Anticipation
Crash risk
Horizontal curve
Predictability
Structural equation modelling

http://resolver.tudelft.nl/uuid:720c7697-54c6-4519-a567-e755837d118a

https://doi.org/10.1016/j.aap.2023.107075

0001-4575

Accident Analysis & Prevention, 187

Institutional Repository

journal article

© 2023 A.P. Afghari, J. Vos, H. Farah, E. Papadimitriou