Final answer:
If a load extends more than four feet past the body of a vehicle, visibility markings like flags or lights need to be used, and additional measures such as escort vehicles or travel time restrictions may be required by law.
Step-by-step explanation:
When the load extends more than four feet past the body of a vehicle, specific safety measures must be taken to ensure the safety of other vehicles and pedestrians. In most jurisdictions, this involves marking the load with flags or lights to increase its visibility, especially during times when visibility is poor, such as at dusk, dawn, or in inclement weather. Depending on local laws, there may also be requirements to have an escort vehicle following the load-bearing vehicle, or restrictions about traveling at certain times of the day.