Blood Alcohol Concentrations in Chiang Mai Drivers before and after the Amendment of Ministerial Regulation Prescribing Blood Alcohol Level

Abstract

Drunk driving is a major cause of road traffic accidents.  This study aimed to analyze whether the enforcement of the new Ministerial Regulation prescribing blood alcohol levels in 2017 impacted blood alcohol concentrations in road traffic accident cases. The retrospective data were collected from 2016 to 2021 for analyzing whether the number of drunk drivers increased or reduced over 3 consecutive periods: before revising the regulation (2016), during the transition of the regulation (2017) and after the regulation has been launched (2018-2021). The information will be useful for future law enforcement and for raising awareness of the danger of drunk driving. The results represented that the majority of the drivers or riders were men with ages ranging from 20 to 29 years old.  The highest proportion of vehicles used was motorcycles with blood alcohol concentrations ranging from 151 to 200 mg% (170.23 ± 74.64 mg%).  When using the blood alcohol level at 50 mg% as the driving legal limit, 68.8 % of cases were justified as drunk drivers. When the new blood alcohol level of 20 mg% as the driving legal limit was enforced on 20 years old or younger drivers, the number of cases with alcohol levels above the cut-off value and those who were considered as drunk drivers had dropped significantly in 2017 and continually decreased until 2021. However, the trend of driving under the alcohol influence in 20 years old or older drivers remains unclear.