What is harsh braking and why is it an issue?

Braking is a key aspect of driving, and one often neglected when people think about safe driving. In fact, it’s one of the top 10 causes of traffic accidents. And knowing what classes as harsh braking could help improve your telematics score.

What is harsh braking?

Harsh braking, also known as hard braking or sudden braking, occurs when a vehicle slows down sharply over a short period. This typically involves applying the brakes more forcefully than would be needed for a routine, controlled stop.

It can be a necessary response to an unexpected hazard, but it can also indicate driving habits that increase the risk of collision.

Braking suddenly isn’t an automatic indicator of poor driving. For example, braking sharply would be an appropriate response to a car pulling out in front of you.

It's important to distinguish between an isolated incident and frequent harsh braking, which could suggest a habit of leaving too little time or space to react to changing road conditions.

The difference between harsh braking and emergency braking

Harsh braking describes how a vehicle slows down, while emergency braking describes the circumstances that make an immediate stop necessary.

Harsh braking is a sudden reduction in speed. It is usually avoidable, such as when a driver approaches stationary traffic too quickly.

Emergency braking is when a driver needs to brake immediately to respond to an imminent danger.

Sometimes, sudden braking is necessary. However, frequent harsh braking in non-emergency situations can indicate driving habits that increase the risk of collision.

What causes harsh braking?

Harsh braking can result from the road conditions, other road users, driving habits or a combination of all three.

• Traffic conditions: Congestion, queues, merging traffic and sudden changes in traffic flow can all require drivers to reduce their speed quickly.
• Unexpected hazards: A pedestrian entering the road or a vehicle pulling out unexpectedly will require an immediate response that the driver couldn’t have anticipated.
• Following distance: The space between vehicles affects how much time a driver has to respond when the car in front of them slows down. If the gap is too small, a sudden stop by the vehicle ahead may leave drivers forced to brake sharply.
• Speed and road conditions: Driving at higher speeds means covering more distance before you can react to a hazard. Wet or icy roads can also increase stopping distances, making it particularly important to anticipate when you might need to slow down.

What is considered harsh braking?

There is no universal threshold for harsh braking across all vehicles and telematics systems. The precise definition depends on how a system measures changes in speed and identifies sudden deceleration.

Marshmallow Move, for example, records a hard braking event when you reduce your speed suddenly, such as slamming on the brakes in a lower-speed zone or drastically reducing speed on the motorway.

The Highway Code provides a useful guide on distances that it takes to brake at certain speeds.

• 20 mph = 12 metres
• 30 mph = 23 metres
• 40 mph = 36 metres
• 50 mph = 53 metres
• 60 mph = 73 metres
• 70 mph = 96 metres

This shows that if you are driving closer to the car in front than these distances at these speeds, then you might be forced to brake suddenly.

What are the dangers of harsh braking?

Harsh braking can create risks for you, your passengers and other road users. It can also put additional strain on your vehicle.

• Following vehicles may be forced to react suddenly: A sudden stop can cause drivers behind to brake sharply or swerve, potentially leading to a rear-end collision or a chain reaction involving multiple vehicles.
• Loss of vehicle control: Sudden braking can increase the risk of skidding, particularly on slippery roads. The Highway Code identifies harsh braking as one of the factors that can contribute to skidding.
• Passenger safety: Sudden deceleration can also throw passengers forward against their seatbelts and cause unsecured items to move around the vehicle.
• Increased wear and tear: Frequent harsh braking can put additional strain on brake pads, discs and tyres, potentially increasing maintenance needs over time.

How can you reduce avoidable harsh braking?

Recent analysis of Marshmallow Move telematics data found that more than half (51.5%) of the drivers analysed received a braking rating of 'Poor' or worse.

Harsh braking can happen for many reasons, and not every sudden stop is avoidable. However, anticipating changes in traffic and allowing more time and space to react can help reduce unnecessary harsh braking.

For practical advice on following distances, speed, hazard awareness and other ways to reduce sudden stops, read our guide to avoiding harsh braking.

How Marshmallow can help

If you’re looking for car insurance that provides feedback to help you drive safely, Marshmallow Move can help.

You’ll get data directly in the app on your braking, speeding and phone use. Plus you’ll get a lower price up front, with a fixed price all year.

Find out more about Marshmallow Move telematics or get a quote today.

Harsh braking as on of the top 10 causes of traffic accidents as reported by Gov.uk.