Driving Combination Vehicles: Turns, Braking, Skid Recovery, Railroad Crossings
What this domain covers
This domain tests how a tractor-trailer behaves in motion. You need to plan turns for off-tracking, brake earlier than a car driver would, recover from skids without overcorrecting, and treat railroad crossings as high-risk decision points.
Turns
- A combination vehicle off-tracks: the rear wheels follow a shorter path than the front wheels.
- Swing wide, but do not swing into another lane. Start the turn from the proper lane and watch the trailer in both mirrors.
- Do not turn too soon. The trailer can cut the corner and hit a curb, sign, or vehicle.
Braking and skids
- Brake early and smoothly. Controlled braking means applying the brakes as hard as possible without locking the wheels while holding the steering wheel steady.
- Stab braking means applying fully, releasing when wheels lock, and reapplying. It is not the preferred method for a loaded combination on dry pavement.
- For a rear-wheel skid, steer in the direction you want the front of the vehicle to go. Release enough braking to let the wheels roll again.
- For a front-wheel skid, release the brakes and straighten the wheel; you cannot steer until the front tires regain traction.
Railroad crossings
- Never stop on the tracks. Check that you have enough room to clear the crossing completely before starting across.
- A combination vehicle carrying hazardous materials must stop before the tracks unless a police officer or flagger directs it across.
Worked example
You turn right at a tight intersection and the trailer’s rear wheels clip the curb. Reasoning: you turned too soon and did not allow for off-tracking. Next time, pull farther forward, swing wider without crossing lane lines, and watch the trailer’s rear wheels in the mirror.
Traps
- Braking hard in a curve.
- Overcorrecting a skid.
- Stopping on railroad tracks because traffic ahead is backed up.