safety features of a car

The safety features of your car

Safety features on cars have improved significantly over the past few decades, but it’s worth understanding what each feature is and how it works. These features aren’t as funky as your new alloy wheels or your Apple CarPlay, but they might just save your life!

How do I know how safe my car is?


We all hear about a car’s EuroNCAP rating, but what does the term actually mean? In simple terms, a EuroNCAP rating gives an indication of how safe a car is, the name coming from the European New Car Assessment Programme.

This independent body takes new cars and slams them into various walls and blocks, to see how they withstand impacts.  But it’s not just about a car’s strength; EuroNCAP also looks at what kit is fitted as standard, such as ESP (Electronic Stability Programme), seatbelt reminders and speed limiters.

Until 2009, all cars were awarded a star rating according to how well they looked after adult or child occupants, as well as how little damage they did to pedestrians. But the system has now changed so that one overall rating is given to the car – which means that to get a five-star award, the car has to be fitted with lots of safety features, be very strong so it looks after its occupants both large and small and it also can’t mangle pedestrians too much.



Also known as Supplementary Restraint Systems (SRS), airbags are designed to stop the human body coming into contact with potentially damaging hard points in a car, in the event of a collision.

As the name suggests, they’re designed to be used in addition to a seat belt – not instead of one. An airbag has to slow a car occupant’s forward motion as evenly as possible in a fraction of a second.

Three areas help to accomplish this feat; the first is a bag made of a thin nylon, which is folded into the steering wheel, dashboard, seat or door.

Triggering this is a sensor that tells the bag to inflate, if a collision takes place over 10-15mph. The airbag’s inflation system reacts sodium azide with potassium nitrate to produce nitrogen gas, a hot blast of which inflates the airbag. All of this happens in just 1/25 of a second, with the bag bursting from its storage area at around 200mph.

However, because the bag is full of tiny holes, it deflates almost immediately, so it’s all over before you can even register what’s happened. Despite the speed of it all, it’s reckoned that the fitment of an airbag reduces the chance of death or serious injury by around a third – so it’s not just a load of hot air.

Anti-lock brakes

It’s only natural; in a panic situation you jump on the brakes, lock the wheels and skid out of control. But not if you’ve got an anti-lock braking system (ABS), which sense when a wheel is about to lock up, then back off the brakes for you.

Even if you keep that middle pedal planted to the floor, the electronic gizmo responsible will release the brakes for you, then as soon as the braking is reduced the system builds up the pressure again, taking the wheel back to the point of locking once more.

It does this 50 times each second; reckon you could compete with that? It’s all down to sensors at each wheel, which work out when a tyre is losing its grip and starting to lock up.

As soon as a loss of traction is detected, the brakes are momentarily released, before being reapplied to keep the wheel on the point of locking, but not actually allowing a skid to develop.

This way, maximum braking power is always being applied, but the wheels aren’t allowed to lock – ensuring you don’t lose your steering because of locked wheels. The key thing though is that anti-lock brakes don’t necessarily reduce your stopping distance – but they do prevent you from locking the wheels and losing control.

So don’t be tempted to sit closer to the car in front, or brake later, just because your car has ABS.


ESP (Electronic stability programme)

You’re buying a used car. You’ve found one you like – in great condition, with 16-inch alloys and a leather steering wheel.

Are you going to ask whether it has ESP? ’Course not. Who cares? Alex didn’t. He’s been driving for five years and he knows about ESP and what it does. We’ll get to the techy bit later but, put simply, ESP (electronic stability programme) helps to prevent you skidding out of control – which is the cause of most fatal road accidents.

It can happen when you go too fast into a bend, when something pulls out in front of you and you swerve, or even when you hit a pothole on a twisty stretch of road. No one is immune.

Even so, Alex didn’t particularly want ESP on his own car. He didn’t see the need. So we took him to Brands Hatch and introduced him to race instructor Phil Brough.

“I get angry at those magazines which talk about ESP being ‘intrusive’ and spoiling the ‘feel’ of a car,” said Phil. “What a load of rubbish. ESP only cuts in when the car has started to go out of control. How is that ruining your fun on the road? It doesn’t brake all four wheels to slow you down: speed isn’t the important thing. It just brakes individual wheels to help steer the car.”

Phil stuck Alex in the passenger seat of a Honda Civic – which has ESP, but gives you the option of switching it off – and took him round a slalom course at full pelt. “To demonstrate how useful ESP is, the car needs to go out of control,” said Phil.

“Trouble is, a Honda Civic is such a good car that you have to really wellie it, building the speed up to 50 or 60mph through the slalom to get it unsettled. That’s why we do this on a closed bit of Brands Hatch: you couldn’t try it safely on a public road. And when we switch the ESP off, Alex is really going to notice the difference… I think he might be surprised.”

Phil then let Alex try the car for himself – first with ESP on; then with it off. Alex proved himself a pretty good driver. With the ESP on, he didn’t spin, even when hurtling through the slalom at 50mph. But with the ESC switched off, it was a different story. First time round the cones and… oops. Round he went…

According to Bosch, which invented ESP, fitting it to every car in Europe would save 20,000 lives over the next five years. But the system can’t be retro-fitted. The only solution is to buy a car which has ESP in the first place.

It’s now compulsory for all new designs of cars to have ESP but, many smaller, cheaper used ones don’t – and they’re the ones that need it most. So, whether you’re buying new or used, ask the question. Does it have ESP? If it does, you’re 25% less likely to die in a road accident. Worth it, or not? You decide.

What’s in a name?

ESP has more than 20 different names, from ESC (Electronic Stability Control) and VSC (Vehicle Stability Control) to DSC (Dynamic Stability Control) and ASTC (Active Stability & Traction Control System). But they all work in the same way to help you avoid a crash.