2013 Session: 652

• The effect of combined speed and red light cameras on safety
  Abstract: This study evaluates the traffic safety effect of combined speed and red light cameras on 253 intersections in Flanders-Belgium that were installed between 2002 and 2007. The adopted approach was an Empirical Bayes before- and after study. The evolution in the number of crashes at the investigated locations was compared with the evolution in a comparison group of locations. These analyses show a non-significant increase of 5% in the number of injury crashes. For the severe crashes, with serious and fatal injuries, a decrease of 14% was found, significant at the 10% level. A distinction between side and rear-end crashes showed a significant increase of 44% in the number of rear-end crashes, but a non-significant decrease of 6% in the number of side collisions. The decrease for the severe crashes was mainly attributable to the effect on side-collisions, for which a decrease of 24% was found, also significant at the 10% level. Furthermore ANOVA-analyses showed RLC-equipped intersections outside the urban area yield more favorable results, compared to intersections inside the urban area.
  Authors: De Pauw, Ellen; Daniels, Stijn; Brijs, Tom; Hermans, Elke; Wets, Geert
  Authors: De Pauw, Ellen; Daniels, Stijn; Brijs, Tom; Hermans, Elke; Wets, Geert
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-1970
• Impacts of Speed Cameras on Road Accidents: Application of Propensity Score-Matching Methods
  Abstract: This paper aims to evaluate the impacts of speed limit enforcement cameras on reducing road accidents in the UK. The propensity score matching (PSM) method is employed to control for selection bias and selecting proper reference groups. A naive before and after approach and the empirical Bayes (EB) method are compared with the PSM method. We observe 771 sites and 4787 sites for the treatment and the potential reference groups respectively for a period of 9 years. Both the PSM and the EB methods show similar results that there are significant reductions in accidents number at all severities at speed camera sites. It is suggested that the propensity score can be used as the criteria for selecting the reference group in before-after control studies.
  Authors: Li, Haojie; Graham, Daniel; Majumdar, Arnab
  Authors: Li, Haojie; Graham, Daniel; Majumdar, Arnab
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-2554
• Effect of Speed Control with Mobile Radar With or Without Advanced Warning Sign: Statistical Analysis on Speeding Behavior
  Abstract: Speeding is an important risk factor in road safety. Generally, this risk factor plays a role in one out of three fatal crashes. Speed enforcement is one of the measures to tackle this problem. In this paper, we investigate the effect of a stationary police control in an unmarked police car equipped with a mobile radar with and without an advance warning sign alongside the road section. These two methods were tested on two road segments of regional roads (70 km/h and 90 km/h) in the Flemish region of Belgium by means of two field experiments. Since the use of a warning sign raises the visibility of the covert speed control we assume - partly based on previous research - that the effect on speeding behavior will be higher and longer lasting (than without the advance warning sign). The effect of both methods is evaluated by means of descriptive analyses, significance tests and multiple linear regression analyses. In this paper, we present the results of these analyses with respect to a frequently used speed behavioral indicator namely the 85th percentile of speed (“V85”). Analysis of the general effect of both enforcement methods, show a larger effect of the speed control with advanced warning sign (- 10 km/h) than for the speed control only (- 5 km/h). Results with regard to the effect in time are less conclusive. However, regression models, show only a longer lasting effect for the combination of the advanced warning sign with the speed control.
  Authors: Wilmots, Brenda; Hermans, Elke; Brijs, Tom; Wets, Geert
  Authors: Wilmots, Brenda; Hermans, Elke; Brijs, Tom; Wets, Geert
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-5358
• Effect of Speed Control with Mobile Radar With or Without Advanced Warning Sign: Statistical Analysis on Speeding Behavior
  Authors: Hermans, Elke
  Authors: Hermans, Elke
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-5358
• The effect of combined speed and red light cameras on safety
  Authors: De Pauw, Ellen
  Authors: De Pauw, Ellen
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-1970
• Impacts of Speed Cameras on Road Accidents: Application of Propensity Score-Matching Methods
  Authors: Li, Haojie
  Authors: Li, Haojie
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 652
  Paper Number: 13-2554