Which rule is suggested for backing a straight bus?

When backing a straight bus, the most effective practice involves using mirrors to maintain visibility and to ensure safety. This is crucial because large vehicles like buses have significant blind spots, and relying solely on mirrors can help the driver monitor their surroundings more effectively.

Using a spotter can also be a beneficial practice, particularly in tight spaces or crowded areas, as a spotter can provide real-time feedback about the bus's position and help prevent accidents. Backing up quickly is generally not advisable, as doing so can increase the risk of collisions and reduce the driver's ability to react to any unexpected obstacles or pedestrians.

Therefore, the best rule to follow when backing a straight bus is to always utilize mirrors, ensuring that the driver can adequately scan the area behind and around the bus while maneuvering in reverse.