What Is the Best Stopping Brake At Speed?
Speed is a critical factor in all road crashes and casualties. Driving is unpredictable and if something unexpected happens on the road ahead – such as a child stepping out from between parked cars – it is a driver’s speed that will determine whether they can stop in time and, if they can’t stop, how hard they will hit.
Reducing and managing traffic speeds is crucial to road safety. Breaking the speed limit or travelling too fast for conditions is recorded (by police at crash scenes) as a contributory factor in almost one in four (24%) fatal crashes. This is arguably a gross underestimate, because whether or not a vehicle is judged to have been speeding or going too fast for conditions, the fact it was involved in a collision means it was going too fast to have stopped in time. In this way, speed is always a contributory factor, albeit often in combination with other causes: no one was ever killed by a stationary vehicle.
Dutch research has found drivers with one speeding violation annually are twice as likely to crash as those with none, and this increases further for drivers who commit repeated speed violations .
The simple truth about speeding is: the faster you go, the longer it takes to stop and, if you crash, the harder the impact. Even small increases in speed could have severe consequences. If a pedestrian steps out into the path of an oncoming vehicle which is speeding the difference could be a matter of life or death.
Which Factors are affecting the Braking/Stopping distance?
An effective braking system and driver ability behind the wheel are most important to ensure swift and safe braking. There are however also a few other factors to consider:
Tyres and braking: Tyres are one of the most important elements when stopping a vehicle quickly and efficiently. One of the factors used in calculating braking distance is traction coefficient. The higher the traction coefficient is, the shorter the braking distance will be. Braking distance can change greatly based on the type and condition of the vehicle’s tyres. Tyres with little or no tread will be more susceptible to skidding during heavy braking. When the tyres skid (a decrease of the traction coefficient), they lose traction and increase the braking distance. The tyre compound or makeup can also change braking distance. Some high performance tyres offer better adhesion under heavy braking and won’t break loose or skid as easily as harder tyres.
Braking and Suspension Systems: If any of these components aren’t up to specification or in poor condition, the vehicle’s braking distance can change. Worn brake drums, rotors, pads, shoes or leaky brake lines will have an adverse effect on braking. Since weight transfer has so much to do with braking, worn shock absorbers and springs will only add distance during braking. When these components are worn, the weight wants to move to the front of the vehicle when you hit the brakes hard. [See Shock Absorbers and Safe Driving]
Road conditions: The condition of the road and our ability to adapt to these conditions will affect braking distance. Dirt and gravel roads don’t offer good traction and increase braking distance. Freshly paved asphalt offers the best adhesion.
Weather Conditions: We always need to consider the weather conditions and how this impacts on the road surface and the vehicle. Wet roads increase braking distance. Snowy and icy roads decrease traction even more.
Driver ability: Driver experience and knowing your vehicle are important for safe and fast braking. Drivers can only benefit from additional driver training and advanced driving courses to enhance their driving skills.
The Braking system: Whether or not the vehicle is equipped with an anti-lock braking system (ABS) must also be taken into consideration in calculating stopping distances.