title: Drivers' behavioral responses to combined speed and red light cameras.
abstract: BACKGROUND
  Numerous signalized intersections worldwide have been equipped with enforcement cameras in order to tackle red light running and often also to enforce speed limits. However, various impact evaluation studies of red light cameras (RLCs) showed an increase of rear-end collisions (up to 44%).
  
  
  OBJECTIVE
  The principal objective of this study is to provide a better insight in possible explaining factors for the increase in rear-end collisions that is caused by placing combined speed and red light cameras (SRLCs).
  
  
  METHODS
  Real-world observations and driving simulator-based observations are combined. Video recordings at two signalized intersections where SRLCs were about to be installed are used to analyze rear-end conflicts, interactions and driver behavior in two conditions (i.e., with and without SRLC). Furthermore, one of these intersections was rebuilt in a driving simulator equipped with an eye tracking system. At this location, two test conditions (i.e., SRLC and SRLC with a warning sign) and one control condition (i.e., no SRLC) are examined. The data of 63 participants were used to estimate the risk of rear-end collisions by means of a Monte Carlo Simulation.
  
  
  RESULTS
  The results of the on-site observation study reveal decreases in the number of red and yellow light violations, a shift (i.e., closer to the stop line) in the dilemma zone and a time headway reduction after the installation of the SRLC. Based on the driving simulator data, the odds of rear-end collisions (compared to the control condition) for the conditions with SRLC and SRLC+warning sign is 6.42 and 4.01, respectively.
  
  
  CONCLUSIONS
  The real-world and driving simulator observations indicate that the risk of rear-end collisions increases when SRLCs are installed. However, this risk might decrease when a warning sign is placed upstream.
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: evelien.polders@uhasselt.be.
authors.forename: Evelien
authors.initials: E
authors.lastname: Polders
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: joris.cornu@uhasselt.be.
authors.forename: Joris
authors.initials: J
authors.lastname: Cornu
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: tim.deceunynck@uhasselt.be.
authors.forename: Tim
authors.initials: T
authors.lastname: De Ceunynck
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: stijn.daniels@uhasselt.be.
authors.forename: Stijn
authors.initials: S
authors.lastname: Daniels
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: kris.brijs@uhasselt.be.
authors.forename: Kris
authors.initials: K
authors.lastname: Brijs
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: tom.brijs@uhasselt.be.
authors.forename: Tom
authors.initials: T
authors.lastname: Brijs
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: elke.hermans@uhasselt.be.
authors.forename: Elke
authors.initials: E
authors.lastname: Hermans
authors.affiliation: Hasselt University, Transportation Research Institute, Wetenschapspark 5/6, BE-3590 Diepenbeek, Belgium. Electronic address: geert.wets@uhasselt.be.
authors.forename: Geert
authors.initials: G
authors.lastname: Wets
mesh_terms: D000054:Acceleration; D000063:Accidents, Traffic / Q000331:legislation & jurisprudence / Q000517:prevention & control* / Q000523:psychology / Q000706:statistics & numerical data*; D000328:Adult; D000368:Aged; D001334:Automobile Driving / Q000331:legislation & jurisprudence / Q000523:psychology* / Q000706:statistics & numerical data*; D001530:Belgium; D003198:Computer Simulation; D005260:Female; D006801:Humans; D035846:Law Enforcement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009010:Monte Carlo Method; D010781:Photography / Q000295:instrumentation* / Q000331:legislation & jurisprudence; D018570:Risk Assessment / Q000706:statistics & numerical data; D014741:Video Recording / Q000331:legislation & jurisprudence; D055815:Young Adult
keywords: Behavior; Combined speed and red light cameras (SRLCs); Conflict observation; Driving simulator; Enforcement