Driving with a trailer

By the end of this topic you can

• You can choose a safe towing speed and follow your state's towing speed and lane rules.
• You can leave enough following distance and plan stops early.
• You can make wide turns so the trailer wheels clear curbs and other vehicles.
• You can control speed on long downgrades without overheating the brakes.
• You can respond calmly and correctly to trailer sway.

What you need to know and understand

• There is no national towing speed limit; some states set a lower limit for vehicles towing trailers. California, for example, limits towing vehicles to 55 mph.
• Several states require towing vehicles to stay in the right-hand lane except when passing or turning; California is one of them.
• Stopping distance grows with weight, so increase your following distance well beyond what you use in a car.
• Trailer wheels track inside the tow vehicle's path on turns, so you must swing wider and go further into the intersection before turning.
• If the trailer blocks your view to the rear, extended side mirrors are typically required; California requires mirrors giving a view at least 200 feet behind.
• On long downgrades, a lower gear does most of the work and the brakes only help.
• Many states, including California, require slow vehicles holding up five or more vehicles on a two-lane road to pull over at a safe turnout.

Speed, space and lanes

Drive below the posted limit when it suits the trailer, the road and the wind, and never above any special towing limit in your state. Speed is the biggest factor in sway, so keeping it modest is your best protection.

Leave a big gap in front, start braking earlier than usual and give yourself more room to merge and pass. When you change lanes, remember the rig may be twice as long as your car; check both mirrors and wait until you can see the vehicle you passed in your mirror with a clear gap.

Turns, curves and hills

On a right turn, pull further forward and keep away from the curb before turning so the trailer wheels do not climb it. On curves, slow down before you enter, not in the middle.

Climbing, stay in the right lane and accept a lower speed. Going down, shift to a lower gear before the grade starts. If you must brake, use firm, short applications rather than riding the pedal, which can lead to brake fade.

• Watch for signs that ban trailers or warn of steep grades, low clearance or weight-limited bridges
• Use truck escape ramps if your brakes fail on a mountain grade
• Take extra care in crosswinds; slowing down is usually the best defense

If the trailer starts to sway

Sway is a side-to-side swing that can grow quickly. It is usually triggered by speed, a gust of wind, a passing truck or a sudden steering input, and made worse by low tongue weight.

1. Take your foot gently off the gas. Do not speed up.
2. Keep the steering wheel as straight as you can; avoid fighting each swing.
3. If you have an electric brake controller, apply the trailer brakes alone gently with the manual lever.
4. Do not slam on the vehicle brakes, which can cause a jackknife.
5. Once slow and stable, pull over safely and check the load, tire pressures and hitch before going on.

Common mistakes

• Driving at car speeds. Slow down, and know any towing speed limit in the states on your route.
• Turning too early, so the trailer wheels hit the curb. Go further into the turn and swing wider.
• Braking hard to stop sway. Ease off the gas and use the trailer brake controller instead.
• Riding the brakes downhill. Pick a low gear before the descent.
• Forgetting the trailer when changing lanes. Use both extended mirrors and allow extra room.

Test yourself: Driving with a trailer

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