Final answer:
To assist a truck driver attempting to pass, safely move to the right lane to allow the truck to pass while maintaining or slightly reducing speed.
Step-by-step explanation:
When a truck is trying to pass your vehicle, the best way to help the truck driver is by moving to the right lane, if safe and possible, to allow the truck to pass. It's important that you maintain your current speed or slightly reduce it to facilitate the truck's passing maneuver.
Actions like speeding up, braking suddenly, or honking your horn are unsafe and can lead to dangerous situations on the road. Always ensure that you're following the rules of the road and being aware of the vehicles around you to maintain safety for all road users.