Sep 22, 2012 - WHY a 50mg LIMIT? by ALCOHOL HEALTHWATCH (New Zealand)

Overseas Limits

Most of the Western world now has a 50mg blood alcohol limit, and international trends have shown that a 50mg limit dramatically reduces drink driving, saves lives, and reduces injuries from alcohol-related road crashes. The greatest reduction was seen in Queensland with an 18 percent reduction in fatal collisions and a 14 percent reduction in serious accidents.

Why a 50mg Limit?

  • International studies have suggested that lower blood alcohol levels may contribute to positive changes in public attitudes toward drinking and driving.
  • Studies have shown that drivers with high blood alcohol concentrations are more likely to underestimate their blood alcohol concentration levels than people with low blood alcohol concentrations6.
  • A lower blood alcohol limit allows the driver the opportunity to make more rational decisions about whether to stop drinking and whether or not to drive.
  • When a 50mg limit is introduced some drivers further restrict their drinking for reasons including:


  • The behavioural chain or sequence is more easily broken early on in the drinking session than in the later stages. By forcing people to consider the issue of drinking and driving at the start of their drinking session it is easier for them to a break the habit.
  •  Lower blood alcohol limits encourage drivers to keep a better count of the drinks they consume in order to stay below the limit. An Australian survey of drinking behaviour suggested that the lower limit made people more aware of the need to control their drinking before driving.

Opponents of a 50mg Blood Alcohol Limit

Many of the opponents to the 50mg blood alcohol level state arguments such as:

  • It is safe to drive at the current level: This is incorrect. There has been much research since the current level was established showing that important driving skills including vision, steering, and braking are adversely affected by even small amounts of alcohol.
  • Lowering the level means that I cannot have my wine with my dinner and then drive home, it also takes the fun out of life: A blood alcohol level of 50mg means that the sensible drinker can still enjoy a glass or two of wine with dinner and then drive. Australian recommendations state that a male can consume two standard drinks (10g) of alcohol in the first hour, and one per hour after that. Females can consume one drink per hour, from the first hour. However there is information to indicate that it is possible to drink even more, and still remain below the lower limit.
  • A lower blood alcohol concentration would cost too much to enforce and is a waste of taxpayers money: While enforcement costs may initially increase, the general deterrent effect of the lower limit should eventually lead to fewer charges and a reduction in the enforcement and courts costs. Moreover the benefits definitely outweigh the costs when considering the lives saved and injuries prevented.
  • Most drink drive deaths are caused by drivers with high blood alcohol levels not those between 50-80mg, therefore a lower limit won’t see great reductions: This argument is only half true. While most of the alcohol-related crashes are caused by highly intoxicated drivers, there is much research showing that a lower limit reduces drunk driving at all levels. Australian research from alcohol tests of crash-involved drivers and from police random breath testing found that the change to the 50mg limit had the greatest impact on reducing the number of drivers with a high blood alcohol concentration.

Source: Healthwatch New Zealand


Last updated on: 2013-07-01 | Link to this post