A system and method efficiently computes travel times between an origin and destination, minimizing expensive calls to a third party service by first geographically expanding both origin and destination and then searching a cache of previously computed or obtained travel times for any route satisfying the expanded origin and destination. A further embodiment concerns a system and method to prepare an optimized routing sequence to travel to a set of geographical task sites, in satisfaction of applicable conditions for one or more of the task sites. Advantageously, optimized routing may employ the disclosed method of computing travel times between origin and destination.