Some states, such as Massachusetts, have online calculators that allow drivers to calculate tolls for trips within the state. However, there is no online calculator available for interstate trips as of 2015. Mapping websites such as Maps.Bing.com, MapQuest.com, and Maps.Google.com indicate toll roads in the driving directions they provide.
Toll rates vary by state and may vary on an individual toll road, based on factors such as the time of travel, vehicle size and method of payment. An interstate traveler can estimate toll costs for a trip by generating driving directions on a mapping website, then searching for the government website for each state of travel to find the toll rates for roads in that state.
Some states use cameras to collect license plate information as vehicles drive over toll roads. If the vehicle has a toll pass for that state, then the toll is withdrawn by automatic debit. Vehicles that do not have passes may have to pay a higher rate. Even for a short trip, it may be less expensive to buy a pass than to pay the higher rate for drivers without passes.
Most mapping websites allow users to generate directions that avoid toll roads. Routes that avoid toll roads may add time, miles and gas expenses to the trip.