Choosing a safe and sustainable car

Features to prevent crashes

ABS (anti-lock) brakes and TCS

An ABS system detects when a wheel locks and starts to skid. It then ‘pumps’ the brake (applying and releasing it) at a much quicker rate than the driver can.

ABS brakes prevent skidding, reduce the stopping distance and allow the car to be steered around an obstacle it would otherwise hit.
Some facts about ABS:

• ABS isn’t automatic – it works only when the brakes are on. It is activated by pressing the brake quickly and firmly, and maintaining pressure.
• Pumping or easing off the brakes, which good drivers do to avoid skidding, stops ABS working.
• ABS will not prevent skids on corners caused by excessive speed. Drivers should never drive faster or follow other cars more closely because they’re in a car with ABS.
• Stopping distance tends to be shorter on wet and slippery roads, but can actually increase on shingle or soft snow.
• When ABS is activated, the brake pedal may vibrate or there may be a thumping noise.

In a car without ABS the driver could correct a potential skid by pumping the brake. But in practice this is hard to do and most drivers will skid. It’s a good idea to do a practical driving course to become familiar with ABS.

TCS (traction control system) is an enhanced version of ABS (anti-lock brakes), which improves traction on slippery surfaces when accelerating.

Active head restraints

An active head restraint will move closer to the head during the crash, reducing the chance of neck extension and whiplash. Although head restraints have been a feature of car interiors for many years, their design has improved over the last couple of decades. Active head restraints are now increasingly common.

Active suspension

Active suspension works by adjusting the 'hardness' of shock absorbers during cornering. This limits the vehicle's roll in the corner and improves road holding and stability. This is often promoted as a feature to improve the driving experience, but the extra stability also reduces the chance of leaving the road or rolling over.

Adaptive cruise control

This is a feature that helps to avoid crashes by slowing down a car on cruise control, as it approaches a slower vehicle ahead. See ITS.

Alcohol interlocks

Alcohol interlocks prevent drinking and driving. The driver must blow into a device on the key fob. If there’s alcohol on the breath, a computer in the fob won’t let the car be started. In some cases, the car can’t even be unlocked without a clear test.

Alcohol interlocks are not yet widely available in New Zealand, but are available in Europe, mainly as a feature for company fleet buyers.

Anti-submarining seats

Anti-submarining seats are designed to stop the driver or passengers sliding down and under their seat belt in a crash. They can also work with ‘pretensioners’ which tighten the seat belt over the hips before a crash, reducing the likelihood of the belt sliding off the hips.

Audible warning devices

Horns are fitted to all cars as warning devices, but you may also like to consider buying a vehicle with an warning beeper that sounds when the vehicle is reversing. These beepers can prevent many crashes in areas with a lot of pedestrians and cyclists, such as city streets and car parks.

Collision notification

Advanced collision notification systems work after a crash. They use in-vehicle sensors, GPS technology and wireless communication to tell rescue services the crash location and in some cases, the number of injured people and the nature of their injuries. See ITS.

Collision warning systems

There are a variety of systems that warn drivers when a collision is likely, including front and rear warnings and intersection collision warnings. See ITS.

Daytime running lamps

These are lights which work during the day. They increase a car’s visibility to other road users, particularly when the car is moving from sunlight into shadow, or at times of poor light such as around dawn and dusk.

Doze alert / drowsy warning

This detects when the driver is showing signs of tiredness, such as fixed staring or slow reactions – and alerts them that they may be fatigued. It can also be called a ‘driver fatigue countermeasure’. See ITS.

Electronic stability control (ESC)

Electronic stability control is a new safety technology that helps drivers to avoid crashes by reducing the danger of skidding.

It uses intelligent sensors to detect when a car has deviated from its steered direction, then reduces engine torque and selectively applies brakes to individual wheels to bring the vehicle back on track. It incorporates the functions of anti-lock braking systems and traction control and is particularly effective during sudden evasive manoeuvres.

• Single vehicle fatal crashes by 32%

Breaking down by vehicle type gives:

• Cars: single vehicle injury crashes by 27%
• 4WDs: single vehicle injury crashes by 68%

How does it work?

Electronic stability control works by using a number of intelligent sensors that detect any loss of control and automatically apply the brake to the relevant wheel, putting your car back on the intended path.

Electronic stability control is of assistance to the driver in:

• correcting impending oversteering or understeering;
• stabilising the car during sudden evasive manoeuvres;
• enhancing handling on gravel patches, such as road shoulders; and
• improving traction on slippery or icy roads.

Not all electronic stability control systems are identical. The hardware is similar, but there are variations in how electronic stability control systems are programmed to respond once loss of control is detected.

Naturally, the degree of effectiveness of electronic stability control is dependent upon the amount of traction between the road and the vehicle. Therefore a vehicle with old, worn or inappropriate tyres (eg: non winter tyres on ice and snow), will have the effectiveness of electronic stability control and other control systems reduced, compared to a vehicle with new tyres or tyres specific to a road environmental condition.

Electronic stability control has many different names including:

• Electronic Stability Program (ESP) - Holden, Audi, Chrysler, Mercedes, Saab, Volkswagen
• Dynamic Stability Control (DSC) - Ford, BMW, Jaguar, Land Rover
• Vehicle Stability/Swerve Control (VSC) - Toyota, Lexus
• Active Stability Control (ASC) - Mitsubishi
• Dynamic Stability And Traction Control - Volvo
• Vehicle Stability Assist - Honda
• Vehicle Dynamic Control - Subaru, Nissan.

EBD and EBA

EBD (electronic brake-force distribution) is also known as EBS (electronic brake stabilisation). This system evens out the braking effect on all four wheels, to make braking more effective, reduce stopping distance and prevent the wheels from locking up.

EBA (emergency brake assist) or EBO, relies on the driver hitting the brake pedal very suddenly, as in an emergency. When the sensors detect sudden braking, the pressure is boosted to apply the brakes faster and stop the vehicle in the shortest possible distance.

Forward collision warning

This is system that senses the distance and closing speed of an object in the path of a car, and sounds an alarm to alert the driver if a collision is likely. See ITS.

GPS

GPS (global positioning system) uses satellite signals to determine your exact location and send this information to the driver. These systems can be fairly sophisticated, showing your car’s position on a street map which is displayed on a screen on the dashboard. GPS allows a driver to keep track of where they are and can suggest the best route to follow to reach a designated location. See ITS.

Headlight cleaning system

This is a feature that is automatically activated to clean the headlights when the windscreen is washed.

ITS

ITS (Intelligent Transport Systems) are systems which use computer monitoring for a range of functions such as redirecting traffic away from congestion, advising drivers of weather and road conditions, and alerting rescue services to accidents.

ITS includes ‘intelligent vehicles’ which have features to help drivers avoid accidents, advise them of congestion and route alternatives. Many ‘driver assistance’ features come under ITS, such as:

• navigation / route guidance to avoid congestion and accidents – GPS based
• vision enhancement for night time driving
• adaptive cruise control – slows down a vehicle on cruise control as it approaches a slower vehicle from behind
• intelligent speed control – GPS tells the vehicle and / or driver what the speed limit in the area is
• lane keeping assistance – can make minor changes to steering to keep car in lane
• roll stability control (Electronic Stability Control - ESC) – prevents loss of control while changing lanes, on blind bends or slippery surfaces
• drowsy driver warning systems.

Some ITS systems include collision warning and avoidance – such as intersection and forward collision warning, obstacle detection, lane change assistance, lane departure warning, rollover warning, road departure warning and rear impact warning.

ITS also includes collision notification, which uses sensors and GPS to advise emergency services of the location of crashes and even the number of injured passengers.

While some ITS systems are starting to be available in cars in New Zealand now, others are still in development and may become common features in cars for some years. Some of the systems that come under ITS depend on a supporting network within the roading system. Without this network, the technology can’t be used. Before paying extra for a car with an ITS system, consider whether you will be able to use it.

Lane departure warning

A buzzer alerts the driver if the car is about to leave its lane. Some cars also have a lane change / merge warning which warns the driver when there is a vehicle in their ‘blind spot’. See ITS.

Night vision technology

These systems use non-visible light frequencies to enhance driver vision.

Reverse assist

This sounds a warning tone to alert the driver if they are about to reverse into something or someone, such as pedestrians and / or children. There are also systems that sound a warning tone to alert people outside the car if they are in the path of a vehicle while it is reversing.

Reversing camera

This is a camera with a screen on the dashboard, which allows the driver to see the road immediately behind them. These are particularly useful for avoiding injury to pedestrians by reversing into them. Some vehicles, such as some SUVs, have limited rear visibility due to being high off the road, or having small rear windscreens.

Intelligent seat belt reminders

These give an audible warning to fasten the seat belt, often rising in volume until the belt is in place.

TCS

TCS (traction control system) is an enhanced version of ABS (anti-lock brakes), which improves traction on slippery surfaces when accelerating. See ABS for more.

Tyre pressure warning

This feature warns the driver if a tyre is under-inflated or flat, which can be dangerous. For more on safe tyre choice and maintenance, see tyres under the basics.