Stopping takes more room than most people think: first you notice, then you react, then the brakes work. Maine's default speed limits and the stopping-distance chart are favorite test material.
What affects total stopping distance:
- Speed: the faster you go, the more time and distance it takes to stop
- Perception time: about ¾ to 1 second for an alert driver to recognize the need to stop
- Reaction time: about ¾ to 1 second to move your foot from gas to brake
- Braking distance: about 158 feet at 50 mph on dry pavement; perception and reaction nearly double it
Know the rule
Posted speed limits don't tell you what speed to drive, only that you may not go faster. If conditions make the posted speed unsafe, you must slow down.
Handbook p. 81 ↗Maine maximum speeds, unless posted otherwise
| Where | Limit |
|---|---|
| Outside business, residential or built-up areas | 45 mph |
| Business, residential or built-up areas | 25 mph |
| Passing a school at recess or opening/closing hours | 15 mph |
Know the rule
Speeding in a school zone brings twice the usual fine. School hours are hard to know, so when in doubt, use extreme care.
Handbook p. 82 ↗Know the rule
Racing and reckless driving are not allowed. You also may not drive so slowly that you block normal traffic, except when safety requires it; some highways post minimum speeds.
Handbook p. 82 ↗Know the rule
Your four tires together have only about one square foot of rubber on the road; its grip depends on road and tire condition.
Handbook p. 82 ↗Stopping distance on dry, level pavement
| Speed | Reaction + braking | Total | Car lengths |
|---|---|---|---|
| 10 mph | 11 + 9 ft | 20 ft | 1 |
| 20 mph | 22 + 23 ft | 45 ft | 3 |
| 30 mph | 33 + 45 ft | 78 ft | 5 |
| 40 mph | 44 + 81 ft | 125 ft | 8 |
| 50 mph | 55 + 133 ft | 188 ft | 13 |
| 60 mph | 66 + 206 ft | 272 ft | 18 |
| 70 mph | 77 + 304 ft | 381 ft | 25 |
Know the rule
Headlights let you see clearly only about 250 feet ahead. Driving faster than about 50 mph on a dark road means you're really "driving blind."
Handbook p. 82 ↗Know the rule
In very heavy rain, a snowstorm or thick fog, if you can't see well even at low speed, pull off the road and wait until conditions improve.
Handbook p. 82 ↗Slow down where you can't see far:
- Blind intersections with trees, bushes or buildings
- Steep hills and sharp curves
- Along parked cars, where people may step out
Reduce speed in heavy traffic and at:
- Shopping centers, parking lots and downtown areas
- Narrow bridges and tunnels
- Toll plazas
- Schools, playgrounds and residential streets
Know the rule
Going faster than traffic means constant passing and more chances for a collision, and saves only a few minutes an hour. Going much slower is just as dangerous; if many cars pass you, slow a bit or pull right to let them by.
Handbook p. 83 ↗Know the rule
When turning off a road, don't slow too early or too much (below 5 to 10 mph). On an expressway, don't slow until you're in the exit lane.
Handbook p. 83 ↗Know the rule
Farm tractors, animal-drawn carts and road maintenance vehicles usually go 25 mph or less and display a red-edged orange slow-moving vehicle triangle.
Handbook p. 84 ↗Put it into practice
You're driving 50 mph and see a deer step onto the road. Before your foot even reaches the brake you've traveled about 55 feet, and it takes about 188 feet in total to stop on dry pavement.