Final answer:
You are in a truck's blind spot if you cannot see the truck's side mirrors. Making sure you're visible to the truck driver is essential to road safety.
Step-by-step explanation:
When driving directly behind a large truck, it's important to be aware of the truck's blind spots. The correct way to determine if you are in the truck's blind spot is if you cannot see the truck's mirrors. If you can see the truck's side mirrors from your driving position, it is more likely that the truck driver can see you. However, if you cannot see the truck's side mirrors, you are probably in the trucker's blind spot and should adjust your position on the road accordingly to ensure your safety and visibility.