Calculating a Safe Speed
Stopping a snowmobile is trickier than stopping a wheeled vehicle on a street or trail. To ensure that you can stop safely in any situation, you must be able to calculate a safe speed based on stopping distances.
- Maintaining a safe speed allows you to control your machine and stop in time to avoid a collision.
- The greater the speed, the greater the stopping distance.
- To determine a safe speed, you must know stopping distances and how to factor in sight distance and reaction time.
- Sight distance is the distance from which you can see and identify a hazard, not necessarily the total distance you can see. You often see an object before you’re able to identify it as a hazard.
- If the stopping distance to an object is greater than the sight distance, you’re in danger of hitting the object.
- Reacting to a sudden need to stop involves these steps:
- Seeing something
- Recognizing it’s a hazard
- Deciding what to do
- Braking or steering around the object
Reaction Time Distance
- Reaction time distance is the distance the snowmobile travels during the time it takes you to react.
- The distance depends on the reaction time (in seconds) and speed (in feet per second), and is calculated as: Reaction Time Distance = Reaction Time x Speed.
- Accidents occur in just a few seconds, so think of your speed in feet per second (multiply mph by 1.46667).
- 15 mph = 22 feet per second
- 30 mph = 44 feet per second
- 45 mph = 66 feet per second
- 60 mph = 88 feet per second
- At 30 mph with a reaction time of three seconds, the reaction time distance is 132 feet (3 sec. x 44 ft./sec.).