Usage-based insurance (UBI), also known as pay as you drive (PAYD), pay how you drive (PHYD) and mile-based auto insurance, is a type of vehicle insurance whereby the costs are dependent upon type of vehicle used, measured against time, distance, behavior and place.
This differs from traditional insurance, which attempts to differentiate and reward "safe" drivers, giving them lower premiums and/or a no-claims bonus. However, conventional differentiation is a reflection of history rather than present patterns of behaviour. This means that it may take a long time before safer (or more reckless) patterns of driving and changes in lifestyle feed through into premiums.