Which side of the vehicle is referred to as the "blind side" when backing?

The side of the vehicle referred to as the "blind side" when backing is primarily considered to be the right side because the driver's position in most vehicles limits visibility to that area. When reversing, the driver's ability to see the right side is often obstructed by the vehicle's structure, making it difficult to detect obstacles or traffic.

In contrast, the left side, which is generally more visible due to the driver's line of sight, is not classified as the blind side. The rear side does have limited visibility, but it is not specifically termed the "blind side" in backing scenarios. The front side may obstruct a driver's view of oncoming vehicles but does not relate to the blind spot created while reversing. Thus, understanding that the right side is typically the most challenging area to monitor while backing up helps to reinforce proper driving and safety practices.