Following distance and space cushion

By the end of this topic you can

• You can measure your following distance by counting seconds.
• You can increase your gap in rain, darkness, heavy traffic and other risky conditions.
• You can stop at a safe distance behind another vehicle in traffic.
• You can manage a tailgater by adding space in front of you.
• You can keep space to the sides of your car on multi-lane roads.

What you need to know and understand

• California recommends the three-second rule.
• Oregon describes a safe gap as 2 to 4 seconds, and 4 seconds or more at speeds above 30 mph. Varies by state: check your state manual.
• You need more space on wet or icy roads, at night, behind motorcycles and large trucks, and when towing.
• When stopped, you should see where the rear tires of the car ahead meet the road.
• If someone tailgates you, increase the gap ahead rather than braking hard.
• Driving in the center of your lane gives space on both sides.

How to count your gap

1. Pick a fixed object ahead, such as a sign, pole or shadow on the road.
2. When the rear of the vehicle ahead passes it, start counting: one-thousand-one, one-thousand-two, one-thousand-three.
3. If your front bumper reaches the object before you finish the count, you are too close.
4. Ease off the gas, let the gap grow, and count again at another object.

When three seconds is not enough

The minimum gap assumes good conditions. Add extra seconds whenever stopping will take longer or your view is limited.

• Wet, snowy or icy roads
• Darkness, fog or heavy rain
• Following a motorcycle, a large truck or a bus that blocks your view
• When towing a trailer or carrying a heavy load
• When someone is tailgating you
• When stopped on a hill, in case the vehicle ahead rolls back
• In or near a work zone, where traffic may stop suddenly
• While you are still learning

Space behind and beside you

You cannot control the driver behind you, but you can make tailgating less dangerous. If someone follows too closely, open up more space in front so you can slow gently and avoid sudden stops. If it is safe, change lanes or let them pass.

To the sides, avoid driving right next to other cars for long, and keep as much space as you can from oncoming traffic. When a car merges in front of you too closely, ease off the gas to rebuild your gap.

Common mistakes

• Judging distance by eye in car lengths. Counting seconds is more reliable at every speed.
• Keeping the same gap in the rain. Add time whenever the road or visibility is poor.
• Braking hard to warn a tailgater. Make space ahead instead.
• Stopping right on the bumper of the car ahead. Leave room to see its rear tires.
• Letting the gap shrink in slow traffic. Recheck your count regularly.

Test yourself: Following distance and space cushion

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• Following Distance