The fuel tax is a per-gallon tax on gasoline and diesel used in cars and trucks for driving on public roads. The state and counties use money from the tax to maintain and improve Hawaii’s roads. The state collects 16 cents for every gallon of fuel sold in Hawaii, which in 2018 added up to about $82 million. This money is dedicated to maintaining and improving the 2,500 lane-miles of state highways across the islands. The county tax rates on gasoline and diesel vary, and the monies are used to maintain and improve roads within each county. The rates are 16.5 cents per gallon on Oahu, 17 cents on Kauai, and 23 cents on Maui, Molokai, Lanai and Big Island.