Pay-As-You-Drive Insurance: Actuarial Considerations

Mileage-Based Rating

Pay-as-you-drive (PAYD) insurance charges premiums based on the number of miles driven, reflecting the strong relationship between exposure (miles) and accident frequency. Actuarial studies consistently show that doubling annual mileage roughly doubles the expected number of accidents. Traditional annual premium structures charge low-mileage and high-mileage drivers the same rate (or use self-reported mileage brackets with limited verification), cross-subsidizing high-mileage drivers at the expense of low-mileage drivers. PAYD programs use odometer readings, telematics devices, or connected car data to verify actual mileage and charge accordingly.

Actuarial Framework

Pricing PAYD insurance requires modeling the relationship between mileage and loss cost while controlling for other rating variables. The per-mile rate is typically calculated by dividing the traditional annual premium by an assumed annual mileage, with adjustments for the non-linear relationship between mileage and risk (some losses occur regardless of driving, such as comprehensive claims). Actuaries must also consider the impact of PAYD on driving behavior (the price signal may reduce driving), adverse selection (low-mileage drivers migrate to PAYD while high-mileage drivers avoid it), and premium variability (monthly premiums fluctuate with driving patterns). Regulatory approval requires demonstrating that per-mile rates are actuarially justified.