Photo: Nasr Al, Pexels
On a long, steep downgrade, shift to a lower gear before you start down and let the engine hold your speed, using the brakes only as needed. Riding the brakes all the way down overheats them until they fade or fail. On hills, assume something is just over every blind crest: slow down so you could stop in the space you can see, and never pass where a hill or curve blocks your view. Runaway truck ramps are for any vehicle that cannot stop, including a car whose brakes have failed. Never stop or park on one or in its path.
Going down steep grades
Use a low gear, not just the brakes
- Shift down before the hill, not halfway down. California’s handbook says shift to a low gear before going down a steep hill. Kentucky says slow down before you start down a grade.
- Let the engine do most of the work. Louisiana’s guide says avoid excessive braking on long downgrades and use engine compression (engine braking) as the main way to control speed.
- Never coast in neutral. Alabama’s manual says the law forbids coasting downhill with the transmission in neutral. In neutral you lose engine braking and rely entirely on the brakes.
In an automatic, your owner’s manual shows how to select a lower gear. Handbooks don’t give a universal speed or gear for downgrades, because it depends on the vehicle and the slope. Follow any posted truck or grade warnings, and treat the speed limit as a maximum, not a target.
Brake fade: why riding the brakes is dangerous
Louisiana’s guide explains that brakes can fade or fail from excessive heat when you use them too much instead of relying on engine braking. If your brakes do fail, Oregon’s advice is to pump the brakes, shift to a lower gear, apply the parking brake slowly, warn others with horn or lights, and ease onto the shoulder once you’ve slowed. More in vehicle emergencies.
Runaway truck ramps and trucks on grades
- Runaway (escape) ramps on long downgrades are built for trucks that are out of control or have lost their brakes (Kentucky). They are not trucks-only in an emergency: Colorado law, for example, lets any driver use one when the ramp is needed to stop the vehicle. Never use one as a pull-off, and never stop or park on one or in its path.
- Watch for fast-approaching trucks on mountain roads and downgrades. If one seems unable to slow down, get out of its way (Kentucky). Oregon says smoking wheels or high speed on a large vehicle can mean brake loss, so leave more space and don’t pass.
- Slow trucks on climbs: large vehicles slow down on steep hills and use the right lane. Kentucky says to avoid the right lane on hills where you can.
- Stopped behind a truck on an upgrade: stay to the left of your lane where the driver can see you, and leave extra space in case the truck rolls back slightly (Kentucky).
See sharing the road with trucks for no-zones.
Hills: blind crests, passing and hill starts
Blind crests
- When you come to a hill or curve, adjust your speed so you can stop for a stalled car or slow vehicle in your lane (Kentucky).
- Don’t stop just over a hill or just around a curve, because other drivers may not see you in time (California, Kentucky).
- Alabama warns that narrow, hilly roads have “blind pockets” where you may not see another car until it’s a few feet away. Use your horn on hazardous curves there.
No passing near hills
| State | Handbook rule |
|---|---|
| California | To pass safely, a hill or curve should be at least one-third of a mile ahead. Don’t pass when approaching a hill or curve if you can’t see whether traffic is coming. |
| Alabama | You may not cross the center line to pass on a curve or hill where you can’t see a clear passing distance of at least 500 feet. |
| Kentucky | Treat a curve or hill as if an oncoming vehicle is there. Don’t start to pass when approaching one. |
Solid yellow lines and no-passing signs often mark these areas, but the rule applies even where there are none. More in passing on rural two-lane roads.
Hill starts
Some road tests include starting on a hill. Kentucky’s road test, for example, lists stopping and starting on a hill. Hold the car on the foot brake (or parking brake), move smoothly to the gas, and release the brake as the car begins to pull so you don’t roll back. In a manual car, practice this in a quiet spot first. Oregon also warns that the car ahead of you may roll back when it starts on a hill, so leave room when you stop behind it. See Vermont’s road test hill start and the Kentucky road skills test checklist.
Parking on a hill
Set the parking brake and leave the car in park (or in gear for a manual). Then turn the wheels (California):
- Downhill: wheels into the curb, or to the right if there’s no curb.
- Uphill with a curb: wheels away from the curb, then let the car roll back gently against it.
- Uphill, no curb: wheels to the right, so the car rolls away from traffic if the brakes fail.
Mountain road rules
- Who backs up? On a steep, narrow road where two vehicles can’t pass, the vehicle facing uphill has the right-of-way. The downhill vehicle backs up, because it has more control when reversing up the hill (California).
- Use your horn on narrow mountain roads where you can’t see at least 200 feet ahead (California).
- Headlights on on mountain roads and in tunnels, even on sunny days (California).
- Snow and ice: going uphill, use just enough power to keep moving without spinning the wheels. Bridges and shaded areas freeze first (Oregon).
- Towing: slow down before every downgrade. See towing a trailer.
Watch for the yellow “Hill” warning sign. Oregon’s manual says it means a steep grade is ahead.
State guides for mountain driving
For state detail on mountain and canyon roads, see Colorado mountain and winter driving and learning to drive in Utah. For licensing in every state, start with learning to drive in the USA.
Sources
- Alabama Law Enforcement Agency, “Alabama Driver Manual”, Driving in Hilly Country and passing rules (alea.gov)
- California DMV, “California Driver’s Handbook”, Sections 5, 6, 7 and 8 (dmv.ca.gov)
- Kentucky State Police, “Kentucky Driver Manual” (updated July 2026), Sharing the Road with Large Vehicles, Passing and Driver Testing (kentuckystatepolice.ky.gov)
- Louisiana Office of Motor Vehicles, “Class D & E Driver’s Guide” (DPSMV 2052, R08/25), Brakes (public.powerdms.com)
- Oregon DMV, “Oregon Driver Manual”, Signs, Sharing the Road and Safe and Responsible Driving (oregon.gov)
- Colorado Revised Statutes, section 42-4-1011, Use of runaway vehicle ramps (olls.info)