Urban road costs tend to be higher than rural costs per vehicle mile, so urban driving costs are increased and rural costs decreased by 25%. Since electric vehicles pay no fuel taxes, their road costs are all external. Rideshare passengers are considered to impose no additional roadway costs. Since public transit buses are often exempt from some fuel taxes their total cost is used, but this would not apply where such exemptions do not exist. A trolley that travels on tracks does not impose road wear costs, but comparable public costs are required to maintain rails and right-of-way.