To reduce or not reduce — that is the blood alcohol question

By Anna Sandiford 28/07/2010


Several posts have got involved in the blood alcohol debate (examples being Blood alcohol, Categories of drunk and Wobbling into the road after a night at the pub….). Should NZ reduce the blood alcohol limit for driving a motor vehicle from 80 mg alc/100 ml blood to 50? The UK still has 80 in blood as the legal limit and we in NZ take a lot of what we do in our justice system from theirs.

One thing that has not so far been mentioned is that the NZ breath alcohol limit for driving a motor vehicle is 400 ug alc/L breath. This is established using a blood:breath ratio in the region of 2100:1. In the UK, this ratio is 2300:1, which means that the legal breath limit is 350 ug/L breath (there are plenty of studies that deal with this issue such as Cobb, P.; Dabbs, M., 1985: Report on the performance of the Lion Intoximeter 3000 and the Camic Breath Analyser evidential breath alcohol measuring instruments during the period 16 April 1984 to 15 October 1984. Her Majesty’s Stationery Office.   Jones, A., 1993: Disappearance rate of ethanol from the blood of human subjects: implications in forensic toxicology. Journal of Forensic Sciences, 38, 104-118, as well as various Home Office data.    The online version of Clarke’s Analysis of Drugs and Poisons will also be receiving an update from one of the world’s leading minds in this area but that will be next year so I can’t say too much more about it).

50 ug alc/L breath might not sound a lot but in a country like NZ that has a severe attitude problem when it comes to drink driving, it could make a difference.