At one time, Hawaii had a network of railroads on each of the larger islands that helped move farm commodities as well as passengers. These railroads were all narrow gauge (3 ft (914 mm) gauge for the majority although there were some 2 ft 6 in (762 mm) gauge on some of the smaller islands – standard US gauge is 4 ft 8 1⁄2 in (1,435 mm)). The largest by far was the Oahu Railway and Land Company (OR&L) which ran multiple lines from Honolulu across the western and northern part of Oahu. The OR&L was an important player moving troops and goods during World War II. Traffic on this line was busy enough that there were signals on the lines facilitating movement of trains and wigwag signals at some railroad crossings for the protection of motorists. The mainline was officially abandoned in 1947, although part of it was bought by the US Navy and operated until 1970. Thirteen miles (21 km) of track remain and preservationists occasionally run trains over a portion of this line.
A system of state highways encircles each main island. Only Oʻahu has federal highways, and is the only area outside the contiguous 48 states to have signed Interstate highways. Travel can be slow due to narrow winding roads, and congestion in cities.
Admiral Clarey Bridge, also known as the Ford Island Bridge, is a floating concrete drawbridge providing access to Ford Island, a United States Navy installation situated in the middle of Pearl Harbor. The causeway bridge was completed and opened in 1998, named the Admiral Clarey Bridge after former AdmiralBernard A. Clarey. The bridge has a total length of 4,700 ft (1,400 m), including a 930 ft (280 m) pontoon section that can be retracted to allow water traffic to pass through.
Nu‘uanu Pali Tunnels are a set of four highway tunnels (two in each direction) on the Pali Highway (Hawaii State Highway 61) which pass through the Nuʻuanu Pali. These tunnels serve as one of three trans-Koʻolau routes between Honolulu (leeward Oʻahu) and the communities of windward Oʻahu.
Also, the Nuuanu Pali Tunnels serve as a major transportation route from Kaneohe & Kailua over to Honolulu.
Private steamships and ferries were the sole way of traveling between the islands from the 19th century until the 1950s.Seaflite operated hydrofoils between the major islands in the mid-1970s. The Hawaii Superferry operated between Oʻahu and Maui between December 2007 and March 2009, with additional routes planned for other islands. Legal issues over environmental impact statements and protests ended the service, though the company operating Superferry has expressed a wish to begin ferry service again at a future date. Currently there is passenger ferry service in Maui County between Moloka'i and Maui, and between Lana'i and Maui, though neither of these takes vehicles. Norwegian Cruise Lines also provides passenger cruise ship service between the islands.