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04-28-97

08-14-95



Night Driving

The faster you drive, the more time and distance you need to stop, and the less time you have to react.

At night, when you can see only as far as your headlights allow, the situation is worse.

Your low beam headlights will allow you to spot an object on the road about 160 feet ahead of your vehicle. Most drivers need about 1.5 seconds to react.

You might be able to swerve and miss an object or person on the road, but you might not. If you are driving too fast, the consequences could be deadly! Take a look at the illustrations and charts, below, to see what we mean...

The charts below are based on a very simple formula:

Reaction Distance + Braking Distance
= Stopping Distance


Definitions:

  • MPH — speed in miles per hour.
     
  • Reaction Distance — how far you will continue to travel before you can physically hit the brakes in response to an obstacle seen ahead or other unexpected braking situation.
     
  • Braking Distance — how far you will travel while you are braking.
     
  • Stopping Distance — the total distance you will have travelled, with everything considered, until you can bring your vehicle to a complete stop.
The charts on this page show each "type" of distance color-coded as shown in the illustration below:




Here are the charts:

At 20mph

As you can see from the first chart, above, even with low beams at 20mph you can react to a problem ahead and come full stop in 69 feet, well short of any obstacle ahead.


At 30mph

At 30mph, the margin of safety is narrower, but if you're watching the road you can still stop in time.


At 40mph

At 40mph, you'd better use your high beams when you can. While you may be able to see highly reflective objects for quite a distance, dark objects like common road hazards, animals on the roadway, etc. will be a BIG problem with just your low beams to help you.


At 50mph

At 50mph, braking alone takes 158 feet of the 160 feet illuminated by your low beams! No time to "react" at all!


At 60mph

Well, at 60mph low beams certainly aren't enough, are they?


At 70mph

At 70mph, if you're really fast you might be able to get to your foot to the brake before impact...


At 80mph

What can we say? At 80mph you only have time to think about braking. Your foot will probably still be on the accelerator pedal at impact.


Obviously there are a lot of factors that can affect the results shown on the charts above:
  • Use your "high" beams whenever possible without blinding oncoming traffic.
     
  • Reduce speed for adverse road and weather conditions. The braking distances illustrated, above, are for dry, level pavement. Wet or icy conditions can greatly affect braking distances.
     
  • Maintain your brakes in good condition. Worn and poorly maintained brakes can affect braking distance. Check your brake fluid level regularly, or have someone do it for you.
     
  • Keep a good set of tires on your car. General tire condition and tread depth affect braking distances.
     
  • Observe speed limits, and allow yourself to drive below the maximum speed limit when required by road and weather conditions. Think safety.
     
  • Know the weather forcast and condition of your car before you get on the highway. Keep your windshield wipers in good condition and check your wiper fluid level on a regular basis.
     
  • Have your headlights checked annually for proper orientation/focus. Test your high and low beams before starting on a trip.
     
    Police officers routinely test their high and low beams at the start of each shift as part of the normal pre-shift vehicle inspection. Before you get on the highway is the time to test headlights, wipers, and check fluid levels.
     
  • Be alert and keep your eyes on the road. If sleepy, find a place to stop or safely pull off the roadway.

When using snow tires, chains or studded tires in the winter, don't presume that enhanced steering or normal start-stop traction applies to emergency braking. While such devices may be quite useful and have dramatic effects under "normal" winter driving conditions, they won't have the same effect degree of effect in a high speed, sustained braking situation.

And, remember, at night, your headlights cannot follow the curves, hills, and dips in the road — there are a lot of dark/blind spots in what you can see with your headlights, high or low, at night — reduce your speed as needed. Bad weather, unexpected actions by other drivers, and fatigue can also affect your driving and what you can see.



Click HERE to go to the NHTSA websiteThe text and graphics on this page were developed by OUPD from information developed by the U.S. Department of Transportation's National Highway Traffic Safety Administration (NHTSA).

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