Approach angle determines the steepest step that a vehicle can approach without its nose grounding. The closer to 90° the better.

Departure angle determines the steepest step that a vehicle can drive off without its tail dragging. The closer to 90° the better.

The Foers Ibex (right) has excellent approach and departure angles.

Ramp-over angle determines the sharpest ridge that a vehicle can drive over without its belly grounding. The sharper this angle is the better.

In this case the LWB Defender (right) is resting on its chassis, the tyres barely touching the ground, i.e. no traction. It had to be man-handled over.