Thursday, 21 November 2019

Highway safety: speed enforcement devices are not enough

A study by the University of Trento published in Economics of Transportation partially contradicts the findings of other studies

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The efforts put forth in recent years to improve road safety on the Italian highway network led to a remarkable decrease in the number of accidents. From 11,300 with 600 casualties in 2001, road accidents went down to a little more than 6,300 with 230 casualties in 2017 (2017 Aiscat report).

Yet more needs to be done, and many actions are underway to further improve these numbers.

A well-known device in use in Italy is the "Safety Tutor", a speed detection system that monitors the average speed of vehicles on highways, adopted at the end of 2005 by Autostrade per l'Italia in agreement with Polizia stradale to limit speed and as an enforcement tool. This system was welcomed as a life-saving device that could reduce car crashes.

However, a study conducted by the Department of Economics and Management of the University of Trento, published days ago in Economics of Transportation, questioned the effectiveness of the system in reducing accidents and casualty rates.

The study was carried out by Mattia Borsati and Michele Cascarano, doctoral students of the Department of Economics and Management of the University of Trento, and Flavio Bazzana, director of the Department:

"We examined the data by excluding other factors that contribute to greater road safety in other ways, like the decrease in traffic due to the economic crisis, improvements on the highway network, and better vehicle safety equipment. The novelty of our study lies in the use of a longitudinal dataset – explained Borsati – and of statistical methods for causal inference. We carried out an econometric analysis of data on the number of accidents occurred between 2001 and 2017 on all 50 Italian highway networks (which means, those that use the Safety Tutor, and those that do not). We found that for a 1/10 increase in the ratio between the kilometres where this technology in is use and the total kilometres of that network, there is a decrease in the number of accidents with injuries of approximately 3.9%. Apart from this positive but limited effect, we did not find any other evidence of the positive impact of the Safety Tutor in reducing deadly car accidents".

Based on the study, the decrease in road deaths on highways in the last fifteen years may have been caused by a combination of factors, including technological innovations in the automotive industry and better road maintenance, which have nothing to do with the implementation of the Safety Tutor.

About the study:
On the impact of average speed enforcement systems in reducing highway accidents: Evidence from the Italian Safety Tutor
Mattia Borsati1., Michele Cascarano 1.2., Flavio Bazzana 1.
1.Department of Economics and Management, University of Trento, Trento, Italy
2.Economic Research Unit, Bank of Italy, Trento, Italy