Pulling Double/Triple Trailers
Pulling Double/Triple Trailers
This domain tests the en route discipline that keeps a multi-trailer combination legal and connected: pre-trip planning, first-stop checks, parking, and periodic walk-arounds.
Core rules
- Plan the route for clearance, weight limits, tight turns, and construction. A route that works for a single trailer may not work for a dolly and rear trailer.
- After coupling, check the rear trailer’s brakes and lights before you move. After driving a short distance, stop and recheck the coupling, safety chains, line routing, and tire condition.
- At each stop, walk around the combination. Check the dolly’s fifth wheel, pintle hook, chains, glad hands, and green cord. Look for chafing, loose plugs, and shifted loads.
- Park on level ground. Set the parking brakes, place chocks if needed, and do not use the trailer hand valve as a parking brake.
- On downgrades, select a safe lower gear and use controlled braking. Do not ride the brakes.
- Give yourself more room for lane changes, merging, and passing; signal early and confirm the rear trailer is clear.
Worked example
After 40 miles you stop for fuel and find the dolly’s air line chafing on the frame. The line has not failed yet, but a chafed line can burst and trigger a rear trailer brake emergency. You reroute the line, check the glad hand, and test the brakes before continuing. The first-stop walk-around exists to catch exactly this kind of wear before it becomes a breakdown.
Traps
- Driving away without checking rear trailer lights.
- Skipping the first-stop recheck.
- Using the trailer hand valve to hold a parked combination.
- Parking on a slope without chocks.
- Riding the brakes on a long downgrade.
- Forgetting that the rear trailer needs room to clear a lane change.