"Deceleration values" refers to the rate at which an object slows down or decreases in speed. It is a measurement of how quickly something goes from moving fast to moving slower. Full definition
With standard tyres on appropriate road surfaces, the wheel brakes generate deceleration values of around 1.4 G. (bugatti.com)
As well as recording drives on circuits, AMG TRACK PACE can also be used to register acceleration such as the sprint from standstill to 100 km / h or over a quarter of a mile as well as deceleration values. (emercedesbenz.com)
Combined with the simultaneous application of the airbrake, an aerodynamic braking function integrated into the rear wing, the Veyron generates breathtaking deceleration values. (bugatti.com)