Car safety features explained

Safety is perhaps the area of car design that’s improved the most in the last 50 years. Modern cars come with a small army of safety features designed to protect you and your passengers in the event of a crash. Not only that, but many also feature a suite of technology working non-stop to avoid a crash happening in the first place.

We’ve put together this handy guide to talk you through the most common safety systems you’ll find on modern cars.

Automatic emergency braking

• Also called: autonomous emergency braking, collision avoidance, forward collision warning, automatic city braking

Car makers have several different names for these systems but they all do more or less the same thing – keep an eye out for obstacles in your path and bring you to a stop if you don’t react in time.

Sensors on your car – often radar, laser or cameras – scan the road ahead for potential hazards. These systems are often best at detecting other vehicles but many are also able to reliably identify cyclists and pedestrians.

If the car detects something in your path and thinks there’s a risk of a collision, it will sound an audible warning noise, usually accompanied by a warning message on the screen. In the event the obstacle appears suddenly, such as a car jumping out in front of you, or if you fail to react to the warning alert in time, the car will hit the brakes to either avoid a crash or reduce its severity.

Blind Spot Monitoring

• Also called: blind spot detection system, blind spot alert, blind spot information system

This system keeps a watchful eye over your blind spots. Using sensors, the car watches out for obstacles in lanes either side of you, or upcoming traffic you might not have seen when merging into another lane. Often, an amber or red icon will flash up in your wing mirror to tell you it’s unsafe to change lanes.

If the car thinks there’s a risk you might collide with a vehicle in an adjacent lane, it will sound a warning to alert you to the danger. Some versions of this system are also able to actively steer your car back into its lane if you’ve begun to drift towards passing traffic.

Lane Keep Assist

• Also called: lane departure warning system, lane assist, lane keeping system

Lane keep assist uses the car’s on-board sensors and systems to determine where the edges of your lane are. It will then attempt to keep you centred in your lane, or will catch you should you start to drift out of your lane.

Some versions of this technology are very subtle, only intervening if they believe you’re about to cross the lane divider, while others can feel more like a nagging nanny, constantly tugging the steering wheel into line.

Adaptive Cruise Control

• Also called: active cruise control, intelligent cruise control, autonomous cruise control, radar cruise control, dynamic cruise control

As the name suggests, this is an evolution of traditional cruise control systems. Where conventional cruise control holds a vehicle at a set speed, adaptive cruise control will hold that speed unless it detects an obstacle or another vehicle in front of you.

Should the adaptive cruise control detect that it’s following another vehicle – and that vehicle is travelling slower than the speed you’ve set your cruise control – it will reduce your speed to match the car in front at a safe following distance.

Once the car in front has cleared your path or you move into an overtaking lane, adaptive cruise control will accelerate you back up to your set cruising speed. This can save a lot of ankle fatigue on long motorway journeys.

Autopilot and semi-autonomous driving systems

• Also called: Traffic Jam Assist, Super Cruise, Blue Cruise, Travel Assist, Driving Assistant Plus, Drive Pilot, ProPilot

Car makers all have different brand names for these semi-autonomous systems. Whatever the name, they combine all the above technologies to manage a car’s acceleration, braking and steering automatically.

These systems often have quite restrictive scenarios where they can be activated. Many are designed for use on motorways with longer sections of driving in the same lane, some are also able to ‘creep’ through traffic without driver input.

It’s important to remember that none of these systems – even ones with names that suggest they can drive by themselves – are truly ‘self driving’. At all times, you need to pay attention to the road and be able to take over without notice in an emergency. Most of these systems will monitor the driver in some way to make sure they’re still paying attention.

Traffic sign detection

• Also called: traffic sign assist, traffic sign recognition, road sign recognition

This system is fairly self explanatory. Your car’s sensors will look out for road signs and, using a little computer wizardry, work out what those signs say and relay that information to you on the dashboard.

This can be handy if you’ve missed a speed limit sign, for example, because the car is keeping a second set of eyes out for traffic guidance.

Intelligent speed assistance

• Also called: speed limiters

Intelligent speed assist uses GPS data or information from the on-board traffic sign detection system to actively keep a car from going over the speed limit. This can help drivers avoid speeding penalties and makes communities safer by limiting dangerous driving habits. Some systems will also preemptively slow you down if they sense that you’re approaching a corner.

The EU has announced it will soon mandate that new vehicles include this system from the factory.

Rear cross traffic alert

• Also called: rear cross traffic monitoring, rear cross traffic assist, rear cross traffic detection

Rear cross traffic alert keeps watch over you when reversing out of bay parking spaces or driveways. Sensors on the car watch for traffic that might cross your path as you reverse.

If the system detects that you might reverse into the path of another vehicle or pedestrian, it’ll warn the driver and hit the brakes to stop you from crashing into them.

Parking sensors

• Also called: park distance control, park assist

Parking sensors are small ultrasonic sensors fitted to your car’s bumper – sometimes on the rear only and sometimes front and rear. These will measure how far your car is from an obstacle when parking, using audio and visual cues to let you know how close you are. This makes tight manoeuvres much easier because it takes out some of the guesswork in positioning your car.

In many modern cars, parking sensors are also combined with a reversing camera, which brings up a live feed from your rear bumper on the infotainment screen, helping you squeeze into tight spaces.

Driver fatigue detection

• Also called: driver monitoring, driver fatigue monitoring, driver drowsiness detection

Driver fatigue detection is included on cars with semi-autonomous systems as a means to make sure the human driver is paying attention while the on-board systems are controlling the car’s speed and steering.

The most common versions will attempt to detect your hand on the steering wheel, either by you moving it slightly, or by capacitive touch sensing. More advanced versions use infrared scanning to track your eye movements, making sure you don’t look away from the road for too long.

Tyre pressure monitoring systems

• Also called: tyre pressure warning system

This system does what it says on the box – it monitors the pressure in your tyres. Driving with under or overinflated tyres can be extremely dangerous, so this system can give you an invaluable early-warning message that you need to get your wheels looked at. Remember to reset your tyre pressure warning system when you pump the tyres up or get new tyres, as the system may notice a change in pressures and warn you that something’s wrong when it might not be.

Anti-lock Brakes (ABS)

• Also called: anti-skid brakes

ABS has been saving lives for decades. This system uses sensors to determine when one or more wheels has locked up under braking. Locking your wheels in this scenario is dangerous because it makes it almost impossible to steer at the same time, and dramatically reduces overall braking performance.

If the ABS detects a wheel locking, it will release the braking pressure on that wheel for a split-second before reapplying it, rapidly repeating this cycle until braking control has been regained. You’ll feel this as a heavy vibration through the brake pedal. Doing this allows the locked wheel to rotate again, while also maintaining a strong braking force, safely slowing the car.

Traction control

Traction control, like ABS, is a component of the overall vehicle stability control, covered below. Traction control detects when a wheel has become overpowered by the engine and is spinning freely without gripping the road surface. In this scenario, traction control will briefly cut engine power to allow that wheel to regain grip of the road, allowing you to stay in control.

Overdriving the wheels without traction control intervening can be dangerous because it can quickly lead to a loss of control – especially in rear-wheel-drive cars.

Electronic stability control

• Also called: electronic stability program, dynamic stability control, active stability control, vehicle stability control

Electronic stability control (ESC) is a natural evolution of ABS and traction control systems. ESC systems use existing sensors for ABS and traction control, along with yaw and G-force sensors to determine if a vehicle has lost stability. These can kick in, for example, if you accidentally enter a corner too quickly, or if you misjudge slippery conditions.

In the event that stability is lost, the car will attempt to regain control. It does this by controlling the brakes individually, as well as cutting power from the engine, to safely bring the car back into line. High-performance cars will often have modes in their stability control systems that allow for a certain amount of ‘enthusiastic’ driving before they intervene.

High-beam assist

• Also called: adaptive high beam, adaptive high beam assist

Unlit roads often require drivers to use their full beams to safely illuminate the way. However, these can easily dazzle other motorists further up the road, necessitating you to turn them on and off repeatedly as you pass traffic.

High-beam assist can help here by automatically detecting when there’s a vehicle ahead of you in your lane or in an oncoming lane, and turning off your high beams for you. Once the traffic passes, the system will automatically turn your high beams back on.

The most advanced vehicles have fully adaptive headlights that can actively shield parts of their beam. This means they can turn off or block out areas that would dazzle other motorists while simultaneously maintaining the rest of the high beam for better illumination.

Take a look at a great choice of safe cars for sale

Motorpoint specialises in nearly new cars, which means you can get some of the latest safety tech for less. Take a look at our picks for the best nearly new safe cars you can buy or, for more information, find out what it takes to get a five-star Euro NCAP safety rating.