Building and validating a dataset for blood alcohol concentration laws: 84 years of policy development across 185 countries

Author(s): Martinez Diaz, Balboa, Nazif-Munoz

Slidedeck Presentation:

BAC PPT_Martinez



Alcohol-related crashes remains a serious public health given its human and economic losses. Enacting a maximum blood alcohol concentration legal limit for drivers (i.e., per se laws) (BACL) effectively reduces alcohol-traffic fatality and injuries. However, little is known on the cultural, economic, political, and social forces determining how and why countries adopt BACL. An essential first step in this endeavor is to trace national and temporal variations in BACL globally.


To build and validate a dataset for national and over time variations in BACL at a global scale.


We searched for BACL and their respective amendments in 185 countries or territories since the first law of its kind in the world (Norway, 1936). The World Health Organization’s (WHO) global status reports on road safety 2009-2018 and the global road safety database (Nazif-Munoz, 2016) served as the initial sources to track national and temporal variations in BACL during the past decade. To cover the entire study period and cross-check available data, two researchers searched and systematized independently legal documents, government gazettes, reports of international or national agencies, articles in scientific journals, proceedings or conference papers, and theses or dissertations. Researchers used Google and Google Scholar as the main search engines, with keywords to identify road traffic laws and, specifically, BACL. No restriction on the searches by language, being assisted by Google Translator or DeepL Translator, was imposed. An iterative and extensive data cross-checking process, considering information from legal documents as the reference standard was conducted. BACL data were extracted in ml% (i.e., mg of alcohol by ml of blood), with country-year as the unit of analysis.


Searches were conducted between December 2020 to November 2021. We have found 247 data points corresponding to 181 countries and no information for four countries (Maldives, Saint Lucia, Tajikistan, and Turkmenistan). Legal documents contributed to most data points (54.8%). BACL have been enacted in 147 countries (81.2%), where the maximum permitted limits varied from 0.15 ml% (first regulations in Belgium and Germany) to 0.00 ml% (nine countries, including three Latin American and the Caribbean countries). Among these countries, most have not changed their BAC limit (n = 98, 66.7%) since they first enacted them, 37 (25.2%) changed their BAC limit once, and 12 (8.2%) changed their BAC limit twice or more times. The pooled BACL limit median across countries and years was 0.05.


Our comprehensive search has enabled us to trace national and temporal variations in BACL – covering 98.9% of world population. Notably, most data points were retrieved from legal documents, ensuring data accuracy and reliability. Half of the countries that have enacted BAC laws per se align with the WHO recommendations for BAC limits. Further, when countries enact for the first time, it is very unlikely they either increase or decrease the BAC limit imposed.


A database of this type will allow us to explore the factors determining the global diffusion of BACL across 84 years in 185 countries.