California Motor Vehicle Code 21804
Entering Onto a Highway
Vehicle code 21804 discusses the way drivers must enter onto or cross a highway. If the driver intends to enter onto a highway from a space of public or private property or an alley, the driver must yield the right-of-way to all closely approaching traffic already present on the highway.
After slowing and yielding, the driver may continue onto the highway if no oncoming vehicles are too close such that entering the road would be hazardous. As the driver enters the highway, however, all the oncoming vehicles must yield so the driver can merge with the flow of traffic and reach an appropriate speed.
Using common sense and being aware of the surroundings is essentially when operating a vehicle and crossing other vehicles' paths. Pulling out into a road too closely to oncoming traffic could cause an accident. Drivers on the road who continue to speed up behind drivers who are merging also cause a hazard.
Making space for other drivers, maintaining a reasonable speed, and keeping a reasonable distance from the vehicle in front are important factors for the success of merging entry roads with highways.