Riding directly alongside another vehicle is discouraged because:

Question

Riding alongside another vehicle is dangerous because you could be riding in the vehicle's blind spot. The driver may enter your lane without warning if they can't see you. The vehicle will also block your route of escape if a hazard arises.

Accepted Answer

You may be in the other vehicle’s blind spot.

Answer

You may have a difficult time getting to a highway exit.

Answer

You may block the driver's view.

Answer

It prevents other drivers from passing both of you.