Decelerometers

Here we will explain what a decelerometer (AKA ‘Tapley’ / Tapley Brake Meter) is, and when it is called into use.

Copied from another website (will need editing):
A Tapley Brake Meter is a scientific instrument, a decelerometer or MOT Brake Tester a Tapley Brake Meter is used as a back up to a Roller Brake Tester within an MOT Testing Station.
A Tapley Brake Meter is in the main used to test 4×4 vehicles or used if a Roller Brake Tester is faulty within an MOT Test station, this decelerometer can also be used to test all types of vehicles, from heavy trucks and buses to vans. A Tapley Brake Testing Meter needs no electrical connections and it’s so portable that you can take the Tapley Meter to the vehicle instead of the other way around.

Separate page, or combined with Roller Brake Testers?