Final answer:
When merging onto an expressway as part of a convoy, you should accelerate to match the speed of traffic and merge smoothly without causing disruption. Hazard lights should be reserved for indicating a hazard, and waiting for an excessively large gap or slowing down could be unsafe.
Step-by-step explanation:
When driving as part of a convoy and needing to merge onto an expressway, the appropriate action is to accelerate and merge into the traffic smoothly. Using hazard lights is not a standard signal for merging. Instead, they should be used to indicate a hazard or a stopped vehicle. It's important to adjust the vehicle's speed to match the flow of traffic on the expressway for a safe merger. Waiting for a very large gap may cause unnecessary delays and could be unsafe if it leads traffic behind you to slow down unexpectedly. Slowing down significantly can also be dangerous and disrupt the flow of the convoy. Make sure to check mirrors and blind spots, signal your intent to merge, and safely align your speed with the vehicles on the expressway before blending into the lane.