How does interpolation work?
Interpolation of the velocity data is done in data processing between the sample points to increase the accuracy of measured data.
For example, during an 80 km/h deceleration the point at which the vehicle crosses 80 km/h may be between two measured samples, i.e. 80.127 and 79.738. Over such a small period of time as one sample it can be assumed that the deceleration or acceleration is linear, and therefore the measurement in time of where the 80 km/h point was crossed is more accurately measured by interpolating between measured samples. This is used to calculate the exact time the vehicle was at 80 km/h.
Note that no vehicle is dynamic enough to exhibit any behavior that cannot be assumed to be anything but linear between the normal time periods of 20 – 100 Hz VBOX samples.