Its a pretty big area, and its somewhat remote. I've never actually been there though.
A quick Google:
The Bonneville Salt Flats is administered by the Bureau of Land Management for public use and enjoyment. Due to its unique geology, history, and scenic beauty, the Bonneville Salt Flats was designated an Area of Critical Environmental Concern in 1985.
Help preserve the Bonneville Salt Flats!
- Stay on existing roads or areas designated for vehicles. Despite the appearance of a hard surface, much of the area is a thin salt crust over soft mud. It easily breaks under the weight of a vehicle.
- Stay off the salt surface when it is covered by water. When wet, the salt surface is soft and easily damaged by vehicles. Furthermore, the salt water is highly corrosive and can "short-out" the electrical system in your vehicle.
- Be prepared for desert conditions. Temperatures can exceed 100 degrees Fahrenheit in the summer and drop well below 0 in the winter.
- There are no facilities or services on the salt flats. Temporary facilities are available during racing events.
- Overnight stays are prohibited on the salt flats. Camping is encouraged on surrounding public lands. Private campgrounds and hookups are available in nearby Wendover, ten miles west of the Bonneville Salt Flats. Other accommodations and services are also available in Wendover. Call 1-866-299-2489 for more information.
http://www.utah.com/playgrounds/bonneville_salt.htm