Following distance

Dangers of Tailgating: The Facts

Driving too close to other vehicles, or tailgating as it is more commonly known, is one of the most widespread dangerous driving behaviours in Australia. Unlike many other dangerous driving behaviours, tailgating doesn’t need to involve inappropriate speed to increase accident risk. Because of this, tailgating is responsible for a high proportion of non-fatal low speed accidents.

As is the case with driving while fatigued and reckless cornering or braking, tailgating can be difficult to police and prevent. Otherwise responsible drivers may indulge in this behaviour because they are not aware of appropriate following distances, or even due to poor eyesight and other factors which impact driver perception of distance.

Tailgating is therefore best addressed by developing awareness of the risks involved, as well as appropriate following distances are at various speeds. Newer cars with automatic braking and active cruise control features are also likely to assist in preventing tailgating accidents in future by automatically enforcing appropriate following distances.

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What is driver tailgating?

Tailgating is driving too close to a leading vehicle, at any speed, where:

  • the tailing driver will have insufficient time to react to prevent a collision with the leading vehicle if it emergency brakes
  • once the tailing driver has applied emergency brakes, there will be insufficient distance between the two vehicles to prevent a collision with the leading driver.

The above definition will typically be applied to situations where the leading vehicle will not come to an immediate stop, and will instead continue moving forward after brakes are applied. This allows for both more time and distance for the tailing driver to react and come to a stop.

However, for maximum safety on the road, tailgating should be considered to be driving at a following distance where the tailing driver will not have sufficient time or distance to avoid a collision if the leading vehicle collides with an immovable object and stops immediately.

Why tailgating is dangerous

Reduced reaction time

As soon as a leading vehicle brakes, a tailing vehicle has a fixed period of time in which the driver can react and apply the brakes before colliding with the leading vehicle.

The closer the tailing driver is to the leading driver, the less time and distance there is available to stop the vehicle. This is particularly noticeable in low speed tailgating accidents, where the trailing driver will frequently collide with the leading driver without even having time to apply their brakes.

The average driver takes between 1.5 and 2 seconds to recognize and respond to a road hazard. However, older drivers can take as long as 2.5 seconds to respond, while any form of distraction will further increase threat recognition and reaction times.

The Queensland government’s transport department provides the following data demonstrating how far a car will travel in the time in the 1.5 seconds it takes the average driver to recognize and respond to the need to brake their vehicle.

SpeedReaction distance

If the distance between two vehicles is less than the reaction distance, the cars will collide if the lead driver brakes and the tailing driver takes 1.5 seconds or more to react to this. Therefore reaction distance is the absolute minimum following distance that should be observed between two vehicles.

Braking distance

Drivers may expect their vehicles to come to an abrupt stop once brakes are fully applied. In reality a car will instead continue moving forward for a distance proportional to its speed at the moment of braking. Wet or icy roads will further increase braking distances.

In many tailgating accidents braking distance may not be a critical factor. This is because, all things being equal, two cars will have similar braking distances when fully applying their brakes. A tailing vehicle may take 50 meters to come to a stop after braking, but the same will apply to the leading vehicle, which compensates for the distance the tailing vehicle requires to come to a stop.

However, braking distance can still become an important factor in a tailgating accident in a couple of scenarios where all things are not equal.

The first of these is where the tailing vehicle’s braking distance is impacted by its weight or the effectiveness of its braking systems. A simple example is a freight vehicle. A freight vehicle will require a much larger distance to come to a stop than a light passenger vehicle in front of it, and therefore needs to take this into account when maintaining a following distance.

The second situation where braking distance becomes important is in rear end accidents in which the leading vehicle comes to an abrupt stop as the result of colliding with an immovable object. In these cases the leading car’s own braking distance is removed from the overall equation. This means that if the tailing vehicle’s following distance is less than the required braking distance, a collision is inevitable even if the tailing driver reacts instantly to the hazard.

The Queensland government’s transport department provide the following data demonstrating braking distances (where brakes are applied with full force) for the average family car at a range of speeds.

SpeedBraking distance (dry roads)Braking distance (wet roads)

If you wish to protect yourself from the risk of a leading vehicle coming to a complete stop, you would therefore need to add the distances in this table onto the following distances required to compensate for reaction times. We’ll cover the appropriate following distances for various scenarios, and how to estimate them in the ‘What this means for you’ section of this report.

Loss of vehicle control

Appropriate following and stopping distances become an abstraction the moment a driver loses control of their vehicle. And this is something that can easily happen when a driver suddenly applies their brakes at full force – particularly at higher speeds.

Emergency braking significantly reduces the performance of a car’s braking systems, and it is easy for the vehicle’s tyres to reach their friction limit in an emergency braking situation and lose contact with the road. Furthermore, any driver who has been indulging in a pattern of hard braking or reckless acceleration or cornering is at increase risk of brake system or tyre grip failure.

As soon as the vehicle experiences loss of traction with the road the braking distance will be increased and the driver may lose partial or complete control of their vehicle’s steering. This in turn increases the risk of involvement in a collision with surrounding vehicles, and means that the car will be travelling at higher speed at the point of collision, increasing the collision’s destructiveness.

Tailgating accident statistics in Australia

Recording of accident types and causes varies between Australian states and territories, and not all of these keep tabs on accident types when compiling accident reports. However, three states do record rear-end collision fatality statistics, which are typically caused by trailing vehicles observing inadequate following distances.

Rear end collision fatalities20122013201420152016

The available stats indicate that while rear end collisions can be lethal, they are not a major cause of road deaths in Australia. One has to dig deeper into the available statistics to understand the risks posed by tailgating.

ACT, which has made impressive progress in reducing its road toll over recent decades, is the only state that compiles detailed statistics on all rear end accidents. These provide a clearer idea of how pervasive tailgating is on Australian roads and how common tailgating accidents are. Most notably, tailgating accidents make up nearly half of reported accidents on the territory’s roads every year.

Rear end collisions in ACT20122013201420152016
Percentage of all accidents45.67%43.84%44.53%44.14%44.58%

What this means for you

It is as easy to cause a tailgating accident as it is to become involved in one due to the negligence of another driver. Therefore to avoid this type of accident you’ll need to understand what appropriate following distances are, as well as how to compensate from poor driving by other road users.

Observe an appropriate following distance

Following distance is determine by using a landmark to time the amount of time it takes you car to reach a roadside feature that the leading vehicle just passed – typically a streetlight. Counting out the number of seconds it takes to reach the feature provides a more effective guide to following distance than attempting to estimate the distance by the physical space between the two vehicles.

A two second following distances is the minimum following distance that should be observed at any speed up to 110 km/h on both dry and wet roads. This will provide just enough time to stop a tailing vehicle in the event that a leading vehicle applies their brakes with full force. However, this relies on the tailing driver reacting to the hazard and braking within two seconds of perceiving it.

Furthermore, a two second following distance will not be sufficient if the tailing driver is in a heavy vehicle, towing a trailer or has any sorts of issues with its tyres or breaking systems.

The two second following distance is therefore not considered safe. Instead a three second following distance is considered sufficient at speeds of up to 110 km/h on both wet and dry road surfaces. This will compensate for the issues mentioned above, and allow the tailing vehicle sufficient time to brake their vehicle.

For optimal safety, a four second following distance should be observed. This will allow the tailing driver sufficient time and distance to bring their vehicle to a complete stop in the event the leading vehicle comes to an abrupt halt.

For more information about following distances, please consult our guide to stopping and following distances.

Be aware of the behaviour of tailing drivers

Even if you exercise due caution while driving, you’re likely to find other drivers observing insufficient following distances. You’ll often have a good sense when someone is driving too close to you, but if you aren’t sure you can use visual cues to estimate the following distance in the same way you would to determine your own following distance.

How to handle a tailgating driver depends on the road and circumstances:

  • If you are driving in multi-lane road, the best way to avoid tailgating is to keep left and only use the right land to overtake. If you are in the right lane and a driver is tailgating, simply move to the left lane and allow them to pass.
  • If you are driving on a single lane road with an emergency lane, you can give way to the tailing driver by briefly entering the emergency lane when it is safe to do so and allowing the tailing driver to pass.
  • If you are on a single lane road without an emergency lane, but which allows passing, move your car to the left of the lane to signal to the tailing driver that they should overtake you.
  • If you are on a winding road without many safe places for passing, slow down on straight sections with passing lanes in order to allow the tailgating driver to pass. In the event they attempt to pass you in a place where overtaking is not safe, slow down as soon as they are out of your lane, as an oncoming vehicle may suddenly force them back into your lane.
  • Do not feel intimidated into driving faster when another driver is tailgating. Rather attempt to maintain a constant speed which makes it as easy as possible for them to time and execute an overtaking manoeuvre.
  • Avoid becoming emotional. The quickest way to resolve a tailgating situation where another driver flashes their lights or otherwise tries to force you out the way is to calmly allow them to overtake. Any retaliatory behaviour can quickly escalate the situation.

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