California Motor Vehicle Code 21751
Sufficient Clearance Necessary for Safe Overtaking
California vehicle code 21751 draws attention to the space that is required to safely pass another vehicle on a two-lane highway. If a driver plans to overtake the vehicle in front of him by passing into the left lane, there must be a sufficient distance ahead where no oncoming vehicle is approaching. Trying to pass a vehicle when an oncoming vehicle is too close is very dangerous and can cause a head-on collision.
Other things to consider when passing vehicles is how long it will take to clear the vehicle in front of you. More space will be required to pass buses or trucks, as they are longer and will require the passing car to be in the left lane for longer. For this same reason, drivers should avoid passing multiple vehicles at one time. After overtaking the single vehicle in front of a driver, he should make his way back into the safety of the right lane until it is safe to pass the next vehicle.
Drivers must also remember that passing is illegal when double yellow lines divide the road. These lines are not to be crossed unless to pull into a driveway on the left hand side or unless traffic signs are posted saying that it is legal.
Attempting to use the right hand shoulder of a vehicle to pass is also illegal and a dangerous move. The right margin is typically full of debris and is normally only used to slow and stop under emergency circumstances. Passing requires a certain amount of acceleration, and speeding through a debris-filled margin to pass a car could result in a flat tire or a collision, especially since the driver in front would not expect a pass from that side.
Drivers should always pass to the left of a vehicle, whether on a two-lane road or multi-lane road.