Headchopper

Track comes close to the riders heads, creating a headchopper effect

A headchopper is any point in a roller coaster where the structure of the ride, theming or another section of track comes close to the rider's heads, or at least appears to do so. The entrance to a tunnel is also a headchopper. A keyhole is a similar feature used on winged roller coasters, where the train travels through a letterbox-shaped hole, often during an in-line twist or zero-g roll.

Safety

On modern roller coasters, headchoppers are designed to be out of reach to the tallest rider with both hands up. However if a rider exceeding the maximum height limit is allowed on, the ride could potentially be dangerous.

Often, a pull through is conducted to check that all scenery and supports are at safe distances from the ride vehicle.

Footchopper

On an inverted roller coaster, footchoppers create the same effect. Footchoppers are designed so that the rider's legs appear to come close to water, the structure of the ride or other scenery.