At the loading dock, the gap between trailer and building is where most serious accidents begin. Trailer creep and premature departure — what the industry calls "dock walk" — have caused thousands of injuries and fatalities worldwide. For decades the default answer was a manual wheel chock: cheap, simple, and almost entirely dependent on human discipline.
Why the manual chock is the weak link
A chock only protects the dock if someone places it, and removes it only after loading ends. On a busy shift it gets forgotten, kicked aside, or skipped under time pressure. There is no electrical interlock and no signal to the forklift operator that the trailer is actually secured. The result: a trailer can drift or pull away while a worker is still on the leveler.
Regulations are raising the baseline
Safety codes are pushing facilities past the loose rubber block. In the U.S., OSHA 29 CFR 1910.178 (powered industrial trucks) and ANSI MH30.1 (dock levelers) frame the expectation; in the EU, EN 1398 sets the safety requirements for dock levellers. Insurers and auditors increasingly expect a positive restraint system. When a chock-only dock causes an incident, liability lands on the facility — not the chock.
The upgrade path: restraint + interlock + signal lights
- Automatic vehicle restraint (rotating hook, shadow hook, or wheel-based) engages the trailer rigging or wheel and holds it through the entire cycle — no human placement required.
- Interlock: the dock leveler and door will not operate until the restraint confirms "secured". Loading physically cannot begin unsafely.
- Signal light tower (red / green): tells the driver in the cab and the dock worker on the floor whether the truck is safe to load or must not depart. It removes the ambiguity a chock always leaves behind.
Manual chock vs. automatic system
- Manual wheel chock — low cost, zero interlock, depends on crew discipline, no status signal.
- Automatic restraint + interlock + signal — higher upfront cost, physically prevents unsafe operation, communicates status with red/green lights, audit-ready.
What buyers should specify
Treat the restraint, interlock, and signal as one safety system, not three add-ons. Confirm it interlocks with your existing leveler and door. Ask suppliers for compliance references (ANSI MH30.1 / EN 1398 where applicable), and don't let a chock-only dock become a liability line item on the next audit.
DORZONE supplies vehicle restraints, control boxes, and signal towers as a matched, interlocked set with the dock leveler and door — specified together, installed together, safe together.