|
|
 |
 |
|
| |
|
What is a Safe Following Distance? |
|
| |
|
Most experienced drivers would agree that the more distance between you and the vehicles around you the more time you have to adjust to developing situations. In the case of an emergency, having enough time can mean the difference between life and death. But, what is a safe distance to keep between your car and other vehicles? This question is not as straightforward as we are sometimes led to believe.
 The distance at which one should follow another vehicle is directly related to the distance required to bring your vehicle to a complete stop, and is in turn dependent on multiple factors.
Total stopping distance involves:
- Human perception time. This relates to the time required for a person to recognise a potential hazard. It is highly variable as some hazards are much more easily perceived than others. Generally, however, this time is assumed to be 0.75 seconds.
- Human reaction time. Once a hazard has been perceived, the driver must respond by applying the brakes. The average reaction time is about 0.75 seconds. It should be noted that, according to the American Association of State Highway and Transportation Officials, it takes the average driver 1.64 seconds to perceive and react to a roadway hazard. Ninety-five percent of people react within 2.5 seconds.
- Vehicle reaction time. This refers to the time it takes for the vehicle to react once the brakes have been applied by the driver. Vehicle reaction time is very quick, usually assumed to be about 0.05 seconds.
- Vehicle braking capability. This refers to the vehicle's ability to come to a complete stop once the brakes have been applied. Many factors affect a vehicle's ability to stop, including:
- speed of vehicle;
- weight of vehicle;
- type and condition of brakes;
- type and condition of tires;
- physical condition of pavement;
- slickness of pavement;
- grade of road.
On the road when following another vehicle, your following distance must be at least enough to provide you with the opportunity to react to a potential hazard. If you are following a vehicle at 100 kilometres per hour and this vehicle brakes suddenly, on average, you will need about one and a half seconds to react. If you do not have this distance between you and the vehicle in front, you will likely not be able to stop in time.
As noted previously, roughly one in twenty people require more than two seconds to react to hazards. In addition, if at first you do not brake with the same intensity as the vehicle in front of you, you will quickly close the gap between you and the other car. Finally, there is no guarantee that the vehicle in front of you will break in time to avoid the hazard, in any case. Thus, we recommend that you keep a distance between you and the vehicle in front of two to three seconds.
|
|
|
