What should a truck driver do when approaching an overhead bridge or underpass marked with a height clearance of '3.6m' while driving a truck measuring 3.8 metres high?

1. Do not attempt to pass under the bridge; stop safely, turn on hazard lights, and choose an authorized alternative bypass route
2. Proceed slowly, since posted clearances always include a safety margin
3. Cross in the centre of the arch, where an arched underpass is highest
4. Continue if the trailer has passed under a bridge of similar appearance before