90% of driver’s reaction depends on vision, and vision is severely limited at night. Depth perception, color recognition and peripheral vision are compromised after sundown. Your low beam headlights will allow you to spot an object on the road about 160 feet ahead of your vehicle. Sometimes you can take evasive action and swerve to miss the object and in some cases you might not be able to. Most drivers need about 1.5 seconds to react. If you are driving too fast, the consequences could be deadly! Driving requires constant attention and focus.
Your equation is Reaction Distance plus Braking Distance equals Stopping Distance. If the reaction time is 1.5 sec and at 60 mph a vehicle travels at 88ft per sec then at 20mph you will react at 44 feet start to brake at 25 feet which equals a stopping distance of 69 feet. At 30 mph that is 66ft + 57ft = 123ft. Remember that your low beams illuminate 160 feet ahead of your vehicle. At 40 mph that is 88ft + 101ft = 189ft. At 50 mph you react at 110 ft brake at 158ft which makes your stopping distance 268ft. At 60 mph 132ft + 227ft = 359ft. At 70 mph 154ft + 310ft = 464ft. At night, your headlights cannot follow the curves, hills and dips in the road, so you must reduce your speed. Bad weather, unexpected actions by other drivers, and fatigue can also affect your driving and what you can see.
The National Safety Council recommends these effective measures to help minimize after-dark dangers:
- Keep all lights and windows on your vehicle clean
- Headlights should be properly aimed
- Do not drink and drive
- Avoid smoking when you drive, nicotine and carbon monoxide hamper night vision
- Increase following distance
- Reduce your speed
- Keep headlights on dim when following another vehicle
- If an oncoming vehicle doesn’t dim their headlights, use the right edge of the road as a steering guide to avoid the glare
- Frequent stops should be made for exercise and snacks-if you’re too tired to drive, stop and rest
Driving when the sun sets is also one of the most difficult times to drive because your eyes are constantly adjusting to the growing darkness.
See the word document or pdf file below to access a chart.