Overview

There are several factors that can affect your blood alcohol concentration (BAC) including:

  • your sex
  • your weight
  • an empty stomach
  • medications
  • mood
  • fatigue level
  • the rate of consumption

Some people can be impaired even after consuming a small amount of alcohol. It is important that you assess your ability to drive regardless of how much you consume.

Impaired driving, regardless of the amount of alcohol consumed, is a criminal offence.

0.05% BAC limit

Under Alberta’s Traffic Safety Act, the Government of Alberta imposes administrative sanctions for drivers with a blood alcohol concentration (BAC) between .05% (50 milligrams of alcohol in 100 millilitres of blood) and .079% (or 79 milligrams of alcohol in 100 millilitres of blood), which is below the legal threshold associated with the Criminal Code of Canada.

Other jurisdictions in Canada impose similar BAC limits. Research on BAC sanctions has indicated that casualty collisions involving alcohol have decreased in jurisdictions with 0.05 BAC limits. (3)

National and international jurisdictions

The results of administrative and legal sanctions at 0.05% across Canada and in other countries.

Canada – results of introducing tougher sanctions at 0.05%

British Columbia (6) – reduced alcohol-related fatalities by 40%

Prince Edward Island – reduced alcohol involvement in fatal crashes from 64% to 36%

Newfoundland and Labrador – reduced alcohol involvement in fatal crashes from 47% to 27%

International – results of lowering the legal limit from 0.08% to 0.05%

Belgium – reduced fatalities by 10% in the first year and by a further 11% in the next year

France (5) – reduced alcohol-related fatalities by 36%

Australia (2, 4)

  • Australian Capital Territory – reduced drinking and driving
    • High BAC (greater than 0.15) by 41%
    • Low BAC (0.05% to 0.08%) by 90%
  • Queensland
    • Reduced fatal collisions by 18% and all serious collisions by 14%
  • New South Wales
    • Reduced fatal collisions by 8%, serious collisions by 7% and single vehicle nighttime collisions by 11%
  • Austria (1)
    • Reduced alcohol-related collisions by 9%

References

  1. Bartl G, Esberger R (2000) Effects of lowering the legal BAC limit in Austria. Proceedings of 15th Conference on Alcohol Drugs and Traffic Safety Stockholm. International Council on Alcohol, Drugs and Traffic Safety.
  2. Brooks C, Zaal D. (1993). Effects of a reduced alcohol limit for driving (PDF, 400 KB). Australia: Federal Office of Road Safety.
  3. Chamberlain, E., and Solomon, R. (2002). “The case for a 0.05% criminal law blood alcohol concentration limit for driving.” (PDF, 324 KB) Injury Prevention 8(Suppl III):iii1-iii17.
  4. Henstridge, J., Homel, R. and Mackay, P. (1997). The Long-Term Effects of Random Breath Testing in Four Australian States: A Time Series Analysis (PDF, 4.4 MB). Canberra: Federal Office of Road Safety.
  5. Mercier-Guyon, C., 1998. Lowering the BAC limit to 0.05: results of the French experience. Paper presented at the Transportation Research Board 77th Annual Meeting, January 11–15, Washington, DC.
  6. Ministry of Public Safety and Solicitor General, British Columbia (November 2011). News Release: B.C.’s tough impaired laws: one year, 45 lives saved.

How alcohol affects you

BAC 0.02%

Typical effects:

  • some loss of judgment
  • relaxation
  • slight body warmth
  • altered mood

Predictable effects on driving:

  • decline in visual functions (rapid tracking of a moving target)
  • decline in ability to perform two task at the same time (divided attention)

BAC 0.05%

Typical effects:

  • exaggerated behaviour
  • may have loss of small-muscle control (for example, focusing your eyes)
  • impaired judgment
  • usually good feeling
  • lowered alertness
  • release of inhibition

Predictable effects on driving:

  • reduced co-ordination
  • reduced ability to track moving objects
  • difficulty steering
  • reduced response to emergency driving situations

BAC 0.08%

Typical effects:

  • muscle co-ordination becomes poor (for example, balance, speech, vision, reaction time and hearing)
  • harder to detect danger
  • judgment, self-control, reasoning and memory are impaired

Predictable effects on driving:

  • loss of concentration
  • short-term memory loss
  • speed control
  • reduced information process capability (for example, signal detection, visual search)
  • impaired perception

BAC 0.10%

Typical effects:

  • clear deterioration of reaction time and control
  • slurred speech, poor co-ordination and slowed thinking

Predictable effects on driving:

  • Reduced ability to maintain lane position and brake appropriately

BAC 0.15%

Typical effects:

  • far less muscle control than normal
  • vomiting may occur (unless this level is reached slowly or a person has developed a tolerance for alcohol)
  • major loss of balance

Predictable effects on driving:

  • Substantial impairment in vehicle control, attention to driving task and in necessary visual and auditory information processing

Source: Centers for Disease Control and Prevention

Increased risk of collisions

The risk of a being in a collision increases with a BAC of 0.05%.

A 2010 Department for Transport (United Kingdom) report found that drivers with a BAC above zero have an increased risk fo being killed in a crash compared to drivers with a BAC of zero.

This risk also increases as the BAC increases.

Driver’s BAC range Increased fatality risk factor compared to drivers with zero BAC
0.02% to 0.05% Three times greater risk
0.05% to 0.08% Six times greater risk
0.08% to 0.10% Eleven times greater risk

The majority of studies examined in one comprehensive literature review report significant impairment and effects on driving ability by 0.05% (1). Impairments were seen in several skill areas, including attention, tracking, perception, psychomotor skills and reaction time.

As shown above, the risk of dying in a collision increases if the driver has been drinking.

Similarly, the risk that a driver will be involved in a crash also increases if they had been drinking. Because most people’s driving performance is impaired at 0.05%, the probability of being involved in a collision increases by 100% in most cases (2).

Sanctions at 0.05% BAC would not interfere with drinking socially, but may discourage excessive consumption (3).

References

  1. Moskowitz & Fiorentino (2000)
  2. Howat, Sleet, and Smith (1991)
  3. Chamberlain & Solomon (2002)

Alberta statistics

Overview

In Alberta, over 5 years, from 2012 to 2016, collisions involving drinking drivers:

  • injured 5,494 people
  • killed 368 people

In 2016 alone, 57 people were killed and 916 injured in alcohol-related collisions.

Investigating police officers report:

  • 1,579 drivers who had consumed some alcohol were involved in casualty collisions and:
    • 134 people died
    • 772 people were seriously injured
    • 1,402 people sustained minor injuries
  • 2,330 impaired drivers were involved in casualty collisions and:
    • 234 people died
    • 1,172 people were seriously injured
    • 2,148 people sustained minor injuries

Who

As the severity of the collision increases, so does the likelihood that the collision involved a drinking driver.

On average in Alberta, one in 6 drivers involved in fatal collisions had been drinking prior to the collision (2012 to 2016). This compares to an average of about one in 32 drivers involved in injury collisions.

Males between 18 and 21 years of age are most likely to have been drinking before a collision.

When

Casualty collisions consist of both fatal and injury collisions. The highest number of casualty collisions involving alcohol occur from May to October.

Most casualty collisions involving alcohol occur on the weekends.

The most likely time for these collisions is between 11 pm and 3 am.

Drinking and driving collisions are often associated with long weekends.

Suspensions and convictions

Over the last 5 years, there have been 34,185 criminal convictions for impaired driving in Alberta (April 1, 2013 to March 31, 2018).

See the complete list of Alberta traffic collision statistics.

Contact

To connect with the Office of Traffic Safety:

Hours: 8:15 am to 12:00 pm, and 1:00 pm to 4:30 pm (open Monday to Friday, closed statutory holidays)
Phone: 780-427-8901
Toll free: 310-0000 before the phone number (in Alberta)
Email: collisiondata@gov.ab.ca

Address:
Main Floor, Twin Atria Building
Room 109, 4999 98 Avenue NW
Edmonton, Alberta  T6B 2X3