Alcohol, drugs, speed and driving
[3-000] Alcohol and road accidents
While alcohol-related road fatalities have trended downward since the 1980s (389 people killed in alcohol-related collisions in 1980, compared with 45 in 2015), in the years preceding 2023, this trend appeared to flatten or increase slightly: Transport for NSW (TfNSW), Attitudes and behaviours in NSW summary report. Drink driving is a factor in about 1 in every 7 fatal collisions in NSW: TfNSW, Alcohol & driving. There are more than twice as many fatal drink driving collisions in regional NSW than in metropolitan areas with 73% of all fatal drink drive collisions occurring in regional NSW: NSW Centre for Road Safety, Drinking & driving. The majority of drink drivers in fatal collisions across NSW are male (87%): NSW Centre for Road Safety, Drinking & driving. Around one third of all fatal drink driving collisions occur between 9 pm and 3 am on Thursday, Friday and Saturday nights: TfNSW, Alcohol and drugs.
Self-reported drink driving
In 2019, 25% of NSW drivers self-reported to have (either “knowingly” or “might have”) driven over the legal blood alcohol concentration (BAC) limit. This was particularly high for those aged 16–25. Female regional drivers aged 16–25 self-reported more drink driving than their metropolitan counterparts whereas male metropolitan drivers aged 16–25 self-reported more drink driving than their regional counterparts. Self-reported “drink drivers” were more likely than all NSW drivers to rely on judging how they feel to determine if they are over the limit, less likely to plan ahead, and more likely to display overconfidence: TfNSW, Drink driving attitudes and behaviours in NSW.
[3-020] Increased risk with alcohol
The risk of a collision increases as the driver’s blood alcohol concentration (BAC) increases such that:
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at 0.05 BAC, the risk is double than at zero BAC
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at 0.08 BAC, the risk is 7 times higher than at zero BAC, and
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at 0.15 BAC, the risk is 25 times higher than at zero BAC: NSW Centre for Road Safety, Drinking & driving.
On Thursday, Friday and Saturday nights about 50% of collisions involve alcohol, and collisions involving alcohol are generally more serious: TfNSW, Road User Handbook.
[3-040] Measuring your blood alcohol concentration
Measuring a person’s blood alcohol concentration (BAC) accurately is impossible without an Australian standards approved breath testing machine. Counting standard drinks to estimate a person’s BAC is often inaccurate because:
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drinks come in non-standard sizes — pre-mixed drinks sold in bottles or cans may contain more than one standard drink
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alcohol concentrations vary between drinks, such as light beer (2.5%), full strength beer (5%), wine (14%) and spirits (40% or higher)
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beer may be served in glass sizes ranging from a middy to a pint. Wine glasses vary in size from 100 ml to 280 ml or more
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drinks are often topped up and therefore it is impossible to know how many standard drinks have been consumed: TfNSW, Alcohol & driving.
Various physiological and situational factors will affect a person’s BAC including:
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Time of day — this can affect the rate at which alcohol is processed.
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Sex — generally males and females process alcohol at different rates such that a woman of the same height and weight as a man drinking the same amount of alcohol may have a higher BAC.
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Age — being older or younger can affect how much alcohol the body can process.
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Size and weight — a person’s size and body fat percentage can influence how quickly alcohol is processed such that a smaller person may have a higher BAC despite drinking the same amount of alcohol.
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Health — many medical conditions and medications can affect how alcohol is processed by the body. A person’s general health condition and level of fitness can affect their ability to process alcohol such that a person’s BAC can be higher if they are feeling unwell, tired or stressed.
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Liver function — an unhealthy liver processes alcohol slower than a healthy liver.
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Food consumption — lack of food in the stomach means faster absorption of alcohol into the blood stream. Eating may slow down the rate at which alcohol is absorbed by the body, but it will not necessarily bring a person’s BAC below the legal limit.
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Tolerance to alcohol — everyone’s body processes alcohol differently so it is impossible to tell how long it will take for a person’s body to react.
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Other drug consumption — this may affect a person’s ability to process alcohol.
See Transport Accident Commission, Drink driving; Alcohol and Drug Foundation, Blood Alcohol Concentration.
[3-060] How alcohol affects driving
Alcohol affects people in different ways and to varying degrees. Some common effects include:
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slowing brain function and reflexes such that drivers cannot respond to situations, make decisions or react quickly
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reducing ability to judge speed and distance
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reducing coordination
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giving a false sense of confidence
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making it harder to multitask
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making drivers feel drowsy or fatigued
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affecting a driver’s sense of balance and coordination.
See TfNSW, Alcohol & driving; TfNSW, Alcohol and drugs.
In the Court of Criminal Appeal decision of Rummukainen v R [2020] NSWCCA 187, in the context of an offence of dangerous driving causing death, the Court observed the road toll in NSW remains at far too high a level and the consumption of alcohol in this case should be seen as significantly increasing the risk to other road users: [29].
[3-080] Zero tolerance approach to drink driving
The NSW Government takes a zero tolerance approach to drink (and drug) driving, to stop drivers putting themselves and others at risk by getting behind the wheel after drinking alcohol (and using drugs): TfNSW, Alcohol and drugs. Transport for NSW does not suggest counting standard drinks as a method of estimating blood alcohol concentration (BAC) due to variations in the factors discussed at [3-040] that may affect a person’s BAC. TfNSW recommends a person does not drink alcohol if they plan to drive: TfNSW, Alcohol & driving.
[3-090] Mandatory Alcohol Interlock Program
The Mandatory Alcohol Interlock Program (MAIP) is a court-ordered requirement for some drink driving offenders. All drivers convicted of mid-range, high-range, repeat and other serious drink driving offences in NSW are required to have an interlock device installed (unless exempted). After serving an initial disqualification, offenders may:
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drive with an interlock device in their vehicle, which requires a negative breath test to start the vehicle, and at other times, or
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serve out a 5-year automatic disqualification period.
See [2-000] Mandatory alcohol interlock program for high range drink drivers, second offence drink drivers and certain other specified offences.
Most offenders who start the MAIP complete the program (91%). Offenders are less likely to start the MAIP if they are:
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already disqualified at the time of the offence
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aged 55 years and above
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Aboriginal, or
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sentenced to imprisonment for the relevant offence.
See S Rahman, Predictors of commencement and completion of the NSW Mandatory Alcohol Interlock Program (2022) 160 Crime and justice: bureau brief 1.
[3-100] Speed and driving
Each year, speeding while driving contributes to about 42% of all road fatalities and 25% of serious injuries: TfNSW, Speed — Fact sheet. Even though drivers aged under 26 years make up only about 14% of all licence holders, in 2021, they were involved in almost 25% of annual road fatalities: TfNSW, Young drivers. Small increases in speed can significantly exacerbate the impact of a collision. In a collision between a car and a pedestrian, there is a 90% chance the pedestrian will survive if the car was travelling at 30km/h, a 60% chance at 40 km/h, and a 10% chance at 50 km/h: TfNSW, Speeding.
In the Court of Criminal Appeal decision of Byrne v R [2021] NSWCCA 185, Bell P (as his Honour then was) (Button J agreeing) said at [5], in the context of a street race resulting in the death of an innocent road user:
… motor vehicles are not playthings or dodgem cars to be raced by young people for fun or thrills and with impunity. They are to be used responsibly and strictly in accordance with the rules of the road. These rules exist not only for the safety of the drivers and passengers themselves, but for pedestrians and other road users. The holding of a driver’s licence conferring the right to drive a motor vehicle is a privilege which carries heavy responsibilities.
[3-120] Illicit drugs and driving
Around 24% of NSW road fatalities (equating to around 79 lives lost) involve illicit drugs, and between 2019 and 2023, 23% of drivers or motorcycle riders who had an illicit drug present in their system, were also over the legal blood alcohol concentration limit. Male drivers make up 85% of drivers of fatal collisions involving illicit drugs, and in 31% of illicit drug-related collisions, the driver is aged between 20 and 29 years. Cannabis is present in a driver’s blood in 69% of fatal collisions involving illicit drugs making it the most common drug present in such collisions. Methylamphetamine is present in a driver’s blood in 43% of fatal illicit drug collisions.
See TfNSW, Illicit drug involvement in NSW fatal crashes 2019-2023; TfNSW, Alcohol and drugs.
[3-140] Drug driving trends
The number of people proceeded against by NSW police for drug driving offences increased significantly between 2014 (1,409 people) and 2023 (13,815 people) — an 836% increase. There is no evidence suggesting these trends are driven by changes in drug use or drug driving behaviours, rather the two main reasons for the growth in drug driving charges are:
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two expansions of the Mobile Drug Testing (MDT) program which increased testing volumes from around 20,000 to 156,000 tests per year, and
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a recent increase in the detection rate from around 2–3% to more than 10%, due to police targeting repeat drug driving offenders.
See A Teperski et al, Trends in drug driving charges, roadside drug testing and drug use in NSW, 2008-2023 (2024) 172 Crime and justice: bureau brief 1.
[3-160] Driving offences generally
“Driving while disqualified” offenders comprise a substantial proportion of offenders appearing before the Local Court, representing approximately 1 in 8 persons charged: P Nelson, Driving while disqualified (2015) 103 Crime and justice: bureau brief 1. Between July 2024 and June 2025, driving while licence disqualified or suspended was the most common driving offence prosecuted in the Local Court with 21,127 people being charged with this offence, representing over 40% of Local Court driving offenders. Drink and drug driving offenders were the second most common type of offenders with more people being charged with drug driving (12,595) than drink driving (9,502). Significantly fewer people were charged with reckless driving not causing serious injury (4,325).
See NSW Bureau of Crime Statistics and Research, NSW Criminal Court Statistics Jul 2020 to Jun 2025.