Abstract
The Vienna Convention on Road Traffic defines the safe distance
traffic rules informally. This could make autonomous vehicle liable
for safe-distance-related accidents because there is no clear
definition of how large a safe distance is. We provide a formally
proven prescriptive definition of a safe distance, and checkers which
can decide whether an autonomous vehicle is obeying the safe distance
rule. Not only does our work apply to the domain of law, but it also
serves as a specification for autonomous vehicle manufacturers and for
online verification of path planners.