|Bonneville Salt Flats|
Aerial view of the Bonneville Salt Flats in 2015; the race track is located in the upper left
|Floor elevation||1,291 m (4,236 ft)|
|Area||40 sq mi (100 km2) |
|Borders on||Interstate 80 in Utah (south)|
West Wendover, Nevada (west)
The Bonneville Salt Flats are a densely packed salt pan in Tooele County in northwestern Utah. The area is a remnant of the Pleistocene Lake Bonneville and is the largest of many salt flats located west of the Great Salt Lake. The property is public land managed by the Bureau of Land Management and is known for land speed records at the "Bonneville Speedway". Access to the flats is open to the public.
Geologist Grove Karl Gilbert named the area after Benjamin Bonneville, a U.S. Army officer who explored the Intermountain West in the 1830s. In 1907 Bill Rishel and two local businessmen tested the suitability of the salt for driving on by taking a Pierce-Arrow onto the surface of the flats.
Entertainment filmed at the salt flats include portions of Knight Rider, Warlock, Independence Day (1996) and its sequel, SLC Punk, Cremaster 2 from Cremaster Cycle, The Brown Bunny, The World's Fastest Indian, Gerry, The Tree of Life, Top Gear, and Pirates of the Caribbean: At World's End. Furthermore, the Pontiac Bonneville (former flagship sedan of the Pontiac motor division), the Triumph Bonneville motorcycle, and the Bonneville International media company are all named for the salt flats.
The Bonneville Salt Flats hosts the annual US Flight Archery Championships. The goal of flight archery is to shoot arrows from bows at the greatest distance possible without regard to hitting a target, and so the vast flat plane of the flats serves as an ideal location to measure the linear distance traveled by arrows without geographic interference. Both the 1977 (archer Don Brown) and 1982 (archer Alan Webster) world records were set at the Bonneville Salt Flats, while the current world record, achieved in 1987 (archer Don Brown), was set at the salt flats near Smith Creek, Nevada.
The thickness of salt crust is a critical factor in racing use of the salt flats. The Bureau of Land Management (BLM) has undertaken multiple studies on the topic; while a 2007 study determined that there was little change in the salt crust thickness from 1988 to 2003,  more recent studies have shown a reduction in thickness, especially in the northwest area where racing occurs. Overall area of the salt flats has reduced significantly over the past several decades. The cause or causes of this remain unclear, but many believe adjacent evaporative potash mining is the primary factor.
Collaboration between racing organizations, the potash mine, and the BLM lead to a pilot program begun in 1998 to release excess brine onto the salt flats during winter. Plans to increase the volume of brine returned to the salt flats are hoped to halt loss of crust thickness, or possibly restore it in places where it has become too thin to sustain human use.
Motorcar racing has taken place at the salt flats since 1914. Racing takes place at part of the Bonneville Salt Flats known as the Bonneville Speedway. There are five major land speed events that take place at the Bonneville Salt Flats. Bonneville "Speed Week" takes place mid-August followed by "World of Speed" in September and the "World Finals" take place early October.
These three events welcome cars, trucks, and motorcycles. The "Bub Motorcycle Speed Trials" are for motorcycles only. World records are contested at the Mike Cook ShootOut in September. The Southern California Timing Association and the Utah Salt Flats Racing Association organizes and plans the multi-vehicle events, but all event promoters contribute to prepping and maintaining the salt. "Speed Week" events in August were canceled for the second year in a row in 2015, due to poor conditions of the salt in certain parts of the flats. The salt flats had been swamped by heavy rains earlier in the year, which usually happens, but the rains also triggered mudslides from surrounding mountains and onto a section of the flats used for the land-speed racing courses.