Lowering the legal alcohol limit in Belgium: Potential effects on the number of traffic victims. (March 2022)

• Record Type: Journal Article
• Authors: Moreau, Nathalie; Martensen, Heike; Daniels, Stijn
• Is Part Of: Accident analysis and prevention. Volume 166(2022)
• Publication Date: 2022-03
• Subjects: Drink-driving -- Zero limit -- Ex ante evaluation -- Belgium; Accidents -- Prevention -- Periodicals; Accident Prevention -- Periodicals; Accidents -- Prévention -- Périodiques; 363.106
• DOI: 10.1016/j.aap.2021.106542
• Languages: English
• ISSNs: 0001-4575

Abstract

Highlights: 10 to 17 out of the 430 fatalities could be prevented every year. The success of the measure depends on its impact on already illegal alcohol levels. The methodology developed can be applied "mutatis mutandis" in other countries. Abstract: Background: Since 1994, the legal limit of Blood Alcohol Concentration (BAC) is 0.5 g/L for the general drivers' population in Belgium. Since 2015, this limit has been lowered to 0.2 g/L for professional drivers. So far, no specific limitation has been adopted for novice drivers in Belgium. Recently, two bills were submitted to the House of Representatives: the first one proposed to impose a zero-limit for every driver, the second one proposed to restrict this zero-limit only to novice drivers. Objective: The present study evaluated the potential impact of the two bills that aim to reduce the legal BAC limit from 0.5 to zero, either for all drivers or for novice drivers only. We elaborated three scenarios related to the BAC categories for which lowering the legal BAC limit to zero would affect drink-driving behaviour: "Targeted BAC levels" scenario assumed that the new policy would impact only the specifically targeted BAC category, i.e., drivers in the category BAC below 0.5 g/L. "Extended impact" scenario corresponded to the "Targeted BAC levels" scenario to which we added a "halo effect" on drivers in the BAC category "0.5 g/L ≤ BAC < 0.8 g/L". "Broad range impact" scenario corresponded to the "Extended impact" scenario to where we extended the "halo effect" to drivers in the BAC category "0.8 g/L ≤ BAC < 1.2 g/L". Methods: The effect estimates were based on firstly, scientific literature on risks related to drink-driving at different BAC-levels, secondly data on crashes in Belgium and thirdly data on drink-driving behaviour in Belgium and in other European countries. Results: In case of a zero limit for all drivers, an annual reduction can be expected of 10 to 17 fatalities (i.e., a decrease of 2.4% to 3.9%), 8 to 20 severe injuries (i.e., a decrease of 0.3% to 0.8%) and 135 to 315 slight injuries (i.e., a decrease of 0.4% to 0.8%). In case a zero limit is only applied to novice drivers, an annual decrease can be expected by 2 to 4 fatalities (i.e., a decline of 3.7% to 6.2%), 8 to 16 serious injuries and 135 to 262 slight injuries (i.e., a decline of 1.7% to 3.2% in both cases). Discussion: There is no clear evidence on which of the three scenarios would be the most plausible. As the relative risk of a car crash increases strongly with the BAC level, the success of either measure will strongly depend on its ability to also affect drink driving at concentrations that are forbidden already. This also means that most of the casualties could be prevented if compliance with current rules increased.