DOVER, Del. (AP) — What if motorists paid taxes based on the miles they drive in each state, instead of the gasoline they burn? The concept is being tested with GPS devices recording distance and location up and down the Interstate 95 corridor. The News Journal reports that more than 100 Delaware state employees are trying it out. Commercial vehicles already pay mileage-based user fees, and something has to change to pay for road construction and maintenance costs as electric vehicles and better-mileage cars replace gas-guzzlers. But the idea of tracking private vehicles raises privacy concerns.