When following a truck, what should you ensure to see?

When following a truck, ensuring that you can see the side mirrors of the truck is crucial for safe driving. This visibility indicates that the truck driver can also see your vehicle. It creates a safe zone around both vehicles and significantly reduces the risk of a collision. If you cannot see the truck's side mirrors, you are likely in a blind spot, which is an area where the truck driver has limited or no visibility of vehicles around them. Maintaining this awareness allows for better positioning on the road and enhances overall safety for all drivers involved.

The other options do not provide the same level of safety assurance. For example, seeing the truck's rear lights only informs you that the truck is active on the road but does not indicate whether the driver knows you are behind them. Likewise, attempting to see the truck driver's face is not practical and does not contribute to an understanding of the overall road dynamics. Observing the truck's bed does not provide any useful information about your position relative to the truck or the driver's awareness of your presence. Thus, being able to see the truck's side mirrors is the most effective indicator of a safe following distance.