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The effect of data transformation on the severe event prediction in road traffic using extreme value theory

Chen, Zhankun LU ; Johnsson, Carl LU orcid and D'Agostino, Carmelo LU orcid (2025) In Accident Analysis and Prevention 221.
Abstract

Extreme Value Theory (EVT) is the state-of-the-art method for proactive prediction of accident frequency from traffic interactions on a microscopic scale. The main advantage of using EVT is to predict unobserved critical events based on one or more Surrogate Measures of Safety (SMoS) (single- or multivariate EVT) through a mathematical extrapolation of extreme interactions. Such interactions are quantitatively described by SMoS, which commonly measure the proximity of two road users, increasing the probability of a collision as the proximity decreases. Those events with a higher likelihood of turning into an accident are defined as severe interactions, and they are considered extremes and are used in the EVT model. Since EVT analysis... (More)

Extreme Value Theory (EVT) is the state-of-the-art method for proactive prediction of accident frequency from traffic interactions on a microscopic scale. The main advantage of using EVT is to predict unobserved critical events based on one or more Surrogate Measures of Safety (SMoS) (single- or multivariate EVT) through a mathematical extrapolation of extreme interactions. Such interactions are quantitatively described by SMoS, which commonly measure the proximity of two road users, increasing the probability of a collision as the proximity decreases. Those events with a higher likelihood of turning into an accident are defined as severe interactions, and they are considered extremes and are used in the EVT model. Since EVT analysis focuses on the upper tail of the distribution, decreasing transformations are a prerequisite, without which it is impossible to model the extremes. However, prediction results depend on the shape of the indicators’ distributions. Some studies use simple transformations, such as negation, while others employ nonlinear methods that adjust the relationship between proximity and severity. In the present study, the theory of tail analysis has been used to rigorously formulate the effect of a set of conventional linear and nonlinear transformations of SMoS. The approach was tested on a Swedish dataset, and the effects of the transformations on the prediction of extreme events were evaluated based on an accident model built on local data and Empirical Byes correction. The novelty of this study is that one of the most fundamental concepts in traffic conflict theory, such as conflict-crash relationships, has been examined with mathematical interpretation. The results of this study can be further extended to become a standard procedure in modelling traffic conflicts using EVT.

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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Conflict severity, Crash prediction, Data transformation, Extreme Value Theory, Interaction severity, Surrogate Measures of Safety, Tail analysis, Traffic safety, VRU
in
Accident Analysis and Prevention
volume
221
article number
108186
pages
15 pages
publisher
Elsevier
external identifiers
  • scopus:105012919232
ISSN
0001-4575
DOI
10.1016/j.aap.2025.108186
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 The Author(s)
id
48e00e8b-b0c4-46ab-8fc5-f9af972bd6d0
date added to LUP
2025-08-22 05:39:52
date last changed
2025-08-25 09:29:30
@article{48e00e8b-b0c4-46ab-8fc5-f9af972bd6d0,
  abstract     = {{<p>Extreme Value Theory (EVT) is the state-of-the-art method for proactive prediction of accident frequency from traffic interactions on a microscopic scale. The main advantage of using EVT is to predict unobserved critical events based on one or more Surrogate Measures of Safety (SMoS) (single- or multivariate EVT) through a mathematical extrapolation of extreme interactions. Such interactions are quantitatively described by SMoS, which commonly measure the proximity of two road users, increasing the probability of a collision as the proximity decreases. Those events with a higher likelihood of turning into an accident are defined as severe interactions, and they are considered extremes and are used in the EVT model. Since EVT analysis focuses on the upper tail of the distribution, decreasing transformations are a prerequisite, without which it is impossible to model the extremes. However, prediction results depend on the shape of the indicators’ distributions. Some studies use simple transformations, such as negation, while others employ nonlinear methods that adjust the relationship between proximity and severity. In the present study, the theory of tail analysis has been used to rigorously formulate the effect of a set of conventional linear and nonlinear transformations of SMoS. The approach was tested on a Swedish dataset, and the effects of the transformations on the prediction of extreme events were evaluated based on an accident model built on local data and Empirical Byes correction. The novelty of this study is that one of the most fundamental concepts in traffic conflict theory, such as conflict-crash relationships, has been examined with mathematical interpretation. The results of this study can be further extended to become a standard procedure in modelling traffic conflicts using EVT.</p>}},
  author       = {{Chen, Zhankun and Johnsson, Carl and D'Agostino, Carmelo}},
  issn         = {{0001-4575}},
  keywords     = {{Conflict severity; Crash prediction; Data transformation; Extreme Value Theory; Interaction severity; Surrogate Measures of Safety; Tail analysis; Traffic safety; VRU}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Accident Analysis and Prevention}},
  title        = {{The effect of data transformation on the severe event prediction in road traffic using extreme value theory}},
  url          = {{http://dx.doi.org/10.1016/j.aap.2025.108186}},
  doi          = {{10.1016/j.aap.2025.108186}},
  volume       = {{221}},
  year         = {{2025}},
}