Which statement about overhead clearance is true?

The correct statement regarding overhead clearance is that the weight of a vehicle changes its height. When a vehicle is loaded, especially with heavy loads, it can experience a phenomenon known as "squat," where the rear of the vehicle lowers due to the additional weight. This means that the overall height of the vehicle can increase or decrease depending on how it is loaded. It is crucial for drivers, especially of heavy vehicles, to be aware of their vehicle's height in relation to overhead clearances to avoid accidents or damage.

The other statements do not accurately reflect the relationship between vehicle load and height. The height of a vehicle is not consistent when considering load; it can indeed change based on the weight. Similarly, overhead clearance is a significant concern for heavy vehicles, as they often have the potential to surpass height restrictions when loaded. Lastly, most overhead clearances are typically calculated with the height of trucks and buses in mind rather than just passengers, making the consideration of weight and height a crucial factor for safety and compliance.