Bonneville Speedway

Bonneville Speedway (also known as the Bonneville Salt Flats Race Track) is an area of the Bonneville Salt Flats northeast of Wendover, Utah, that is marked out for motor sports. It is particularly noted as the venue for numerous land speed records. The Bonneville Salt Flats Race Track is listed on the National Register of Historic Places.
The salt flats were first used for motor sports in 1912, but did not become truly popular until the 1930s when Ab Jenkins and Sir Malcolm Campbell competed to set land speed records.
A reduction of available racing surface and salt thickness has led to the cancellation of events at Bonneville, such as Speed Week in 2014 and 2015. Available racing surface is much reduced with just 2.5 miles (4.0 km) available instead of the 9-mile (14 km) courses traditionally used for Speed Week.
Historically, the speedway was marked out by the Utah Department of Transportation at the start of each summer. Originally, two tracks were prepared; a 10-mile (16 km) long straightaway for speed trials and an oval or circular track for distance runs, which was typically between 10 and 12 miles (16 and 19 km) long depending on the condition of the salt surface.
Since at least the 1990s, track preparations have been the responsibility of the event organizers. Days or weeks in advance, the track preparers identify an area best suited for their track layouts and begin grading the tracks. Surveyors are brought in to survey the timing trap distances. A day before racing begins, the track markers are added.
Originally, the straightaway was marked with a broad black line down its center. This was eventually changed to lines down either side, as the center line wore out too quickly. As the costs for painting the lines has gone up, organizations have switched to flags and cones as track markers. The last event to use black lines was Speed Week, August 2009.
The number of tracks and the timed sections for each track are set according to what is most beneficial for each event. Large public meets such as Speed Week run as many as four tracks with several timed miles, usually starting with the second mile and running to the fifth mile. Smaller meets that typically only run world record attempts will utilize a single track, with one timed mile and one timed kilometer in the middle of the track. Additional marks and cones indicate the end of the track and the position of timing equipment.
The annual Speed Week was cancelled in both 2014 and 2015, as were many land-speed racing events, due to deteriorating track conditions. Heavy rains caused a layer of mud from surrounding mountains to flow onto the flats, covering approximately 6 mi (9.7 km) of the track. Although another section of the flats would normally be used, nearby salt mining operations had reduced the size of the alternative track.
The depth of the salt crust at Bonneville has also been decreasing, possibly leaching into a saltwater aquifer. Measured at as much at 3 ft (0.91 m) in the 1940s and 50s, it has been reduced to just 2 in (0.051 m) in 2015.
Though recent studies have been made (since 1960), the causes of this deterioration are not clear, although the evidence points toward both local climatic changes and salt mining. Some strategies were devised to revert the decreasing salt surface, such as pumping back salt, though this had no effect.
In August, the Southern California Timing Association and Bonneville Nationals Inc. organize Speed Week, the largest meet of the year, which attracts several hundred drivers who compete to set highest speed in a range of categories. Bonneville Speed Week has been taking place since 1949.
In late August, the Bonneville Motorcycle Speed Trials are held.
In September each year is the World of Speed, (similar to Speed Week) organized by the Utah Salt Flats Racing Association (USFRA). The USFRA also hosts a "Test-n-Tune" event in the summer prior to the World of Speed.
In October, the Southern California Timing Association puts on World Finals, a scaled-down version of Speed Week. This event tends to have cooler weather and often drier salt than Speed Week does. There are less spectators and it tends to draw serious racers, as this event is the last chance to break a land speed record and be in the SCTA record book for that year.
Each year, there are usually a few private meets that are not publicized scattered among the larger public meets.
Numerous land speed records in various vehicle categories and classes have been set on the Bonneville speed way. In 1960, Mickey Thompson became the first American to break the 400 miles per hour (640 km/h) barrier, hitting 406.60 miles per hour (654.36 km/h) and surpassing John Cobb's 1947 one-way Land speed record of 403 miles per hour (649 km/h). Other notable examples of Bonneville speed records include:
Several motor-paced racing speed records have been attempted at Bonneville.
In 1985, American cyclist John Howard set a then world record of 244 km/h (152 mph).
On 15 October 1995, Dutch cyclist Fred Rompelberg achieved 268.831 km/h (167.044 mph), using a special bicycle behind a dragster with a large shield.
In 2016, Denise Mueller-Korenek claimed a women's bicycle land speed record at 147 mph (237 km/h). She was coached by Howard. It is not clear which authority was supervising the record attempt.
In 2018, Mueller-Korenek broke her own women's record and the men's record at a speed of 183.9 miles per hour (296.0 km/h).