Tollguru considers following factors to calculate gas costs for your route
Tollguru™ uses a proprietary algorithm to calculate gas costs based on traffic speeds. For example, fuel efficiency for most cars is 20 percent lower at 75 miles per hour compared to 55 miles per hour. Tollguru uses speeds for each travel leg in a route to calculate gas costs.
The gas costs are estimated using data from users around your location. If no gas cost estimates are known, the toll calculator shows a default gas price that you need to update based on what you paid at the pump.