Sump buster

A sump buster (also known as a sump breaker) is type of bus trap, a device used in urban areas to restrict traffic access on various routes by intentionally destroying the oil pan of any vehicle with an insufficient ground clearance to avoid the obstacle. Similar (in use but not design) to rising bollards, sump busters are often used in bus lanes to prohibit their use by cars.
Function
The sump buster uses a non-mechanical solid mass of concrete (sometimes other aggregates or metal) to demobilise a vehicle when access to a restricted area is attempted. When (for instance) a car attempts to transverse the sump buster, the device will demolish the vehicle's oil pan (literally "busting the sump"). The track (distance between wheels on either side of the vehicle) and ground clearance on permitted vehicles (usually, but not restricted to buses) is such that they may clear the device with ease. In some cases, advisory or mandatory speed limits are given...