Speeding is widely accepted as one of the leading causes of fatalities on our roads – New South Wales statistics show it contributes to about 40% of all road deaths annually,1 while in Victoria speeding is a factor in at least 30% of road deaths each year.2
But what about the opposite – driving too slowly? Is it illegal to drive under the speed limit? The short answer: It can be. Under certain circumstances, driving significantly below the speed limit can become an offence if it unreasonably obstructs other drivers.3
“Speed is one of the key fundamentals of road safety and most people think it only refers to driving over the speed limit,” says Jerome Carslake, Director of the National Road Safety Partnership Program, “but it also applies to driving under and at the speed limit.
“For example, travelling at 20 kilometres per hour on a road with a speed limit of 80 kilometres per hour might be considered driving abnormally slowly and could lead to a fine if it obstructs other drivers.”
Below, we explore how and when slow driving becomes illegal, the penalties you might incur – and how these behaviours could potentially influence your car insurance. We’ll also look at the safety risks of slow driving – and its flipside, tailgating.
When is it illegal to drive under the speed limit?
“In most parts of Australia, slow driving isn’t illegal by itself – however, it can become an offence in certain circumstances,” says Hayley Ferreira, Membership Manager at the Australian Driver Trainers Association.
Rule 125 of the Australian Road Rules, which form the basis of the road rules in each Australian state and territory,4 states: “A driver must not unreasonably obstruct the path of another driver or a pedestrian”.3
However, the rule also states that a driver is not considered to unreasonably obstruct traffic simply because they’re driving more slowly than other vehicles, but that this might occur if a driver is driving “abnormally slowly in the circumstances”.3
Western Australia’s road rules spell things out in a little more detail, citing that drivers on a freeway must travel no more than 20 kilometres per hour below the posted speed limit unless weather, traffic or other conditions prevent them from doing so.5
“Drivers must drive to the conditions – namely, traffic, weather, road conditions – and with respect to other road users, such as oversized vehicles, a school bus or a tram, which may mean that driving under the speed limit is being safe,” says Carslake.
“For example, a truck going down a steep descent must use a low gear, which could be well under the speed limit but is required to control their journey safely.”
The key is reasonableness – driving under the limit because of weather, roadworks, congestion or adverse conditions is generally permitted, according to Rule 125. But driving considerably under the speed limit in clear conditions and causing a delay or hazard may be penalised.
Can you get a fine for driving too slow?
As with speeding fines, fines for unreasonably obstructing other vehicles by driving too slowly vary across Australia, but as there’s no fixed “minimum speed”6, any enforcement of penalties may be at the discretion of police, depending on circumstances.
Queensland drivers face the highest penalties, with the fine for obstructing the path of another driver up to $3,338,7, 8 while for drivers in the Northern Territory, the fine is $40.9
Here’s the full list of penalties for unreasonably obstructing other drivers across Australia.
| State | Fine |
| ACT | $21110 |
| NSW | $33011 |
| Qld | Up to $3,3387,8 |
| SA | $14412 |
| Tas | Up to $1,02513,14 |
| Vic | $407.0215,16 |
| NT | $409 |
In WA, there’s no specific penalty listed for regulation 108 “a driver must not unreasonably obstruct the path of another driver or a pedestrian”;17 however, failing to keep left in a multi-lane road can attract a $50 fine plus two demerit points.18
Penalties for unsafe behaviour on the road vary widely in Australia. From obstructing traffic and not buckling up to using your mobile phone while driving and speeding in a school zone, it may be worth checking in with your local transport authority to find out how each offence is handled in your state or territory.
When can slow driving become a safety risk?
Some drivers might assume driving slow means they’re being extra safe but, according to Ferreira, driving below the speed limit is not always safe or harmless.
“Driving too slowly disrupts the natural traffic flow, leading to sudden braking, tailgating, risky overtaking, and driver frustration – all of which increase crash risk,” says Ferreira.
“Slow driving can be hazardous on high-speed roads where merging or overtaking speeds differ significantly, on motorways or highways, where vehicles behind may not anticipate the slower speed, or on-ramps or roundabouts, where hesitation causes confusion or rear-end collisions.
“We often see this with learners or overly cautious drivers who hesitate when merging or entering traffic flow – which can lead to sudden braking or swerving by others.”
Is tailgating illegal in Australia?
Tailgating – or following too closely behind another vehicle – is explicitly prohibited under road rules in most Australian states and territories, except in the NT.19, 20
But while the NT doesn’t have a specific tailgating rule, the territory’s Motor Vehicle Registry’s Road Users’ Handbook recommends a three-second gap between vehicles.21
“Tailgating remains one of the most common causes of rear-end collisions in Australia. It’s often a by-product of frustration – particularly when drivers feel held up by slower traffic,” says Ferreira.
According to data from the National Road Safety Partnership Program, tailgating contributes to at least 8,000 rear-end crashes annually in Queensland alone, with younger drivers (aged 17 to 25) more likely to tailgate than older drivers.22
Rule 126 of the Australian Road Rules states: “A driver must drive a sufficient distance behind a vehicle travelling in front of the driver so the driver can, if necessary, stop safely to avoid a collision with the vehicle”.3
We’ve outlined the penalties for tailgating, or following too closely to another vehicle, in each state below.
| State | Fine | Demerit Points |
| ACT13 | $447 | 1 |
| NSW10 | $562 | 3 |
| Qld23 | $389 | 1 |
| SA24 | $414 | 1 |
| Tas25 | $202 | 1 |
| Vic26 | $296 | 1 |
| WA18 | $200 | 2 |
How slow driving and tailgating offences could affect your car insurance
Avoiding traffic offences not only helps keep you and other road users safe, it could also help keep your car insurance premiums down, according to Marni Jackson, Youi’s Head of Product – Vehicle and Lifestyle.
“That’s because insurers may take your driving history, including the frequency and severity of any violations, into consideration,” says Jackson. “If you have accrued demerit points, this might lead to a higher premium.”
Tips for safer driving
Here are some practical tips to help you drive more predictably and avoid causing potentially risky situations out on the road:
Keep left unless overtaking
If you’re travelling below the speed limit on a road with a limit in excess of 80km/h, stay in the left (slower) lanes so faster vehicles can pass safely.27
Drive to conditions
Adjust your speed for weather, visibility, road surface and traffic hazards. It’s OK to go under the speed limit, as long as you’re not creating disruption.28
Use the three-second rule
Pick a road marker such as a power pole or tree; when the vehicle ahead passes it, count “one-thousand-one, one-thousand-two, one-thousand-three”. If you reach the marker before finishing, you’re driving too close.29
Anticipate flow and signal early
In merging zones or freeway on-ramps, indicate early and move smoothly into the lane when you see a gap, merging at the same speed as the traffic.30
Stay calm and courteous
Don’t retaliate if tailgated – rein in any frustration or let the tailgater pass safely.31
Use driver assist systems
Modern vehicle safety features such as autonomous emergency braking (AEB) and collision warning systems are designed to help prevent collisions.32, 33 Adaptive cruise control may also help you maintain a safe distance from the car in front.34
1 Source: Transport for NSW – Speed Fact Sheet
2 Source: Vic Government – Road safety camera statistics, August 2025
3 Source: Australasian Parliamentary Counsel Committee – Australian Road Rules, June 2023
4 Source: National Transport Commission – Australian Road Rules
5 Source: Transport WA – Driving offences (speeding, alcohol and traffic), October 2025
6 Source: WhichCar? – Is it illegal to drive ‘too slowly’ in Australia?, November 2023
7 Source: Qld Legislation – Transport Operations (Road Use Management—Road Rules) Regulation 2009
8 Source: Queensland Department of Local Government, Water and Volunteers – Value of a penalty unit, May 2025
9 Source: Northern Territory Legislation – Traffic Regulations 1999
10 Source: ACT Legislation – Road Transport (Offences) Regulation 2005
11 Source: NSW Government – Demerit points - general driving offences
12 Source: South Australia Legislation – Road Traffic (Miscellaneous) Regulations 2014
13 Source: Tas Legislation – Road Rules 2019
14 Source: Tas Department of Justice – Penalty units indexed amounts, July 2025
15 Source: Vic Legislation – Road Safety Road Rules 2017
16 Source: Department of Justice and Community Safety Victoria – Penalties and values
17 Source: Tas Department of Justice – Penalty units indexed amounts, July 2025
18 Source: WA Legislation – Road Traffic Code 2000
19 Source: WA Government – Road rules explained, August 2025
20 Source: Drive – This Australian state is targeting tailgaters, May 2025
21 Source: Car Expert – How much could I be fined for tailgating?, June 2023
22 Source: NT Government – Road Users’ Handbook, August 2020
23 Source: National Road Safety Partnership Program – NRSPP Quick Fact: Rear-end crashes, 2025
24 Source: Queensland Government – Demerit points schedule
25 Source: SA Government – Road rules - Offences and Penalties
26 Source: Tas Government – Find a traffic offence
27 Source: Transport Victoria – Infringement notices (driving fines)
28 Source: NSW Government – Overtaking safely
29 Source: Australian Road Safety Foundation – Safe Driving Practices in Different Conditions
30 Source: SA Government – The Hazard Perception Test - Keeping a safe following distance
31 Source: Transport Victoria – Freeways
32 Source: Crime Stoppers Victoria – Avoidable Accidents: Common Causes of Collisions and How to Drive Safely, November 2024
33 Source: NSW Government – Vehicle safety features
34 Source: Qld Department of Transport and Main Roads – Forward collision avoidance technology, July 2022
35 Source: Drive – How does cruise control actually work?, August 2023
