Safety Rules and Prohibited Operations for Doubles/Triples
Safety Rules and Prohibited Operations for Doubles/Triples
This domain tests the rules that apply specifically to multiple-trailer combinations. Many are prohibitions, so the exam expects you to recognize what you must not do.
Prohibited operations
- Carrying passengers in a trailer.
- Riding on the outside of the vehicle.
- Using the trailer hand valve while driving.
- Coasting in neutral.
- Following too closely for the combination's stopping distance.
Route and speed
- Some roads prohibit doubles/triples; obey posted signs and permit conditions.
- Reduce speed for curves, downgrades, and high winds.
- Obey lower posted limits for trucks where signed.
Following distance
- Allow at least one second for each 10 feet of vehicle length at speeds below 40 mph, and more above 40 mph. For triples, add extra time.
Worked example
You approach a sign prohibiting trailers over a certain length. Even if your combination is legal elsewhere, you must not proceed. Check the route before driving rather than backing out of a restricted road.
Traps
Using the hand valve to "test" brakes while moving, assuming all highways allow triples, and following at the same distance as a single trailer.