Passing is when the driver of slower vehicles uses passing facilities (such as passing lanes, slow vehicle bays and diagonally marked sealed shoulders) to let faster following vehicles pass. Overtaking is when the driver crosses the center line and uses the opposing traffic lane to pass a slower vehicle.

Restriction on overtaking and passing as defined in RA 4136

(a) The driver of a vehicle shall not drive to the left side of the center line of a highway in overtaking or passing another vehicle proceeding in the same direction, unless such left side is clearly visible, and is free of oncoming traffic for a sufficient distance ahead to permit such overtaking or passing to be made in safety.

(b) The driver of a vehicle shall not overtake or pass another vehicle proceeding in the same direction, when approaching the crest of a grade, nor upon a curve in the highway, where the driver's view along the highway is obstructed within a distance of five hundred feet ahead, except on a highway having two or more lanes for movement of traffic in one direction where the driver of a vehicle may overtake or pass another vehicle: Provided, That on a highway within a business or residential district, having two or more lanes for movement of traffic in one direction, the driver of a vehicle may overtake or pass another vehicle on the right.

(c) The driver of a vehicle shall not overtake or pass any other vehicle proceeding in the same direction, at any railway grade crossing, not at any intersection of highways unless such intersection or crossing is controlled by traffic signal, or unless permitted to do so by a watchman or a peace officer, except on a highway having two or more lanes for movement of traffic in one direction where the driver of a vehicle may overtake or pass another vehicle on the right. It shall not be construed to prohibit a driver overtaking or passing upon the right another vehicle which is making or about to make a left turn.

(d) The driver of a vehicle shall not overtake or pass, or attempt to pass, any other vehicle, proceeding in the same direction, between any points indicated by the placing of official temporary warning or caution signs indicating that men are working on the highway.

(e) The driver of a vehicle shall not overtake or pass, or attempt to overtake or pass, any other vehicle proceeding in the same direction in any "no-passing or overtaking zone."