Operational Criteria of Causality for Observational Road Safety Evaluation Studies

Author(s):  
Rune Elvik
Author(s):  
Rune Elvik

The effects on road safety of the “Speak out!” road safety campaign are evaluated. The campaign, which began in Sogn og Fjordane County in Norway in 1993, is targeted toward teenagers and calls on car passengers to act as back-seat drivers and “Speak out!” to drivers about unsafe driving. The campaign’s effects were evaluated by means of two before-and-after studies and and a multivariate Poisson regression analysis. The results of these evaluation studies were very similar. The number of teenagers 16 to 19 years old who were killed or injured was reduced by about 10 percent; the number of occupants in this age group who were killed or injured was reduced by about 15 percent; and the number of car passengers who were killed or injured was reduced by about 30 percent. The number of killed or injured car drivers 16 to 19 years old did not change. Only the reduction among car passengers was statistically significant at the 10 percent level. It is nevertheless concluded that the “Speak out!” campaign has probably been effective in reducing the number of teenagers killed or injured in Sogn og Fjordane. This conclusion is based on a careful discussion of the logic of causal inference in nonexperimental evaluation research. Seven criteria are proposed for attributing causality to the relationship between a measure and changes in the dependent variable that the measure is intended to influence. The majority of these criteria were met in evaluations of the “Speak out!” campaign.


2001 ◽  
Vol 28 (5) ◽  
pp. 804-812 ◽  
Author(s):  
Paul de Leur ◽  
Tarek Sayed

Road safety analysis is typically undertaken using traffic collision data. However, the collision data often suffer from quality and reliability problems. These problems can inhibit the ability of road safety engineers to evaluate and analyze road safety performance. An alternate source of data that characterize the events of a traffic collision is the records that become available from an auto insurance claim. In settling an auto insurance claim, a claim adjuster must make an assessment and determination of the circumstances of the event, recording important contributing factors that led to the crash occurrence. As such, there is an opportunity to access and use the claims data in road safety engineering analysis. This paper presents the results of an initial attempt to use auto insurance claims records in road safety evaluation by developing and applying a claim prediction model. The prediction model will provide an estimate of the number of auto insurance claims that can be expected at signalized intersections in the Vancouver area of British Columbia, Canada. A discussion of the usefulness and application of the claim prediction model will be provided together with a recommendation on how the claims data could be utilized in the future.Key words: road safety improvement programs, auto insurance claims, road safety analysis, prediction models.


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