The current operational infrastructure for Saskatchewan Highways and Transportation (the government department responsible for the operation and preservation of the province’s transportation system) includes more than 131 km of ice roads. The majority of these roads are located in northern Saskatchewan. The only major exception is the Riverhurst Crossing, an ice road constructed each year at Riverhurst and allowing vehicles to cross Lake Diefenbaker. The northern ice roads allow winter access to the communities of Wollaston Lake, Fond du Lac, and Uranium City. During the summer these communities are accessible by either watercraft or aircraft. Many other ice roads previously existed in northern Saskatchewan, but are no longer in commercial use. They included an extension of Highway 955 (Semchuk Trail) to Uranium City, built in 1955–56 by Martin Semchuk, John Midgett and Jonas Clarke; and an ice road from Flin Flon to Reindeer Lake, built by the Sigfusson Transportation Company (Winnipeg) in 1945.