What must a driver do before entering a highway from a private road or driveway?

Before entering a highway from a private road or driveway, a driver must yield the right of way to all vehicles that are already on the highway. This is crucial for ensuring the safety of both the driver entering the highway and the vehicles on the highway, which may be traveling at higher speeds. Yielding the right of way means that the driver must allow any approaching vehicles to pass before merging into the traffic flow.

This requirement is in place to prevent accidents and ensure smooth traffic movement. It encourages drivers to be aware of their surroundings and assess the speed and distance of incoming traffic before making a turn or crossing into the highway. By prioritizing the right of way for oncoming vehicles, drivers are promoting safer driving practices for everyone on the road.

In contrast, other options like sounding the horn, entering quickly, or giving hand signals do not provide the necessary precaution and consideration for oncoming traffic, which could lead to dangerous situations on the road.