these courses still technically fall under the category of ovals, their unique shape, flat corners, hard braking zones, or increased difficulty, often produces driving characteristics similar to those of a road course. Concentric oval track / legends oval Some facilities feature several ovals track of different sizes, often sharing part of the same front straightaway. The now defunct Ascot Speedway featured 1/2 mile and 1/4 mile dirt oval tracks, and Irwindale Speedway features 1/2 mile and 1/3 mile concentric paved oval tracks. Pocono Raceway once had a 3/4 mile oval which connected to the main stretch, and circled around the garage area. In 1991, Charlotte Motor Speedway connected the quad oval start-finish straight to the pit lane with two 180 degree turns, resulting in a concentric 1/4-mile oval layout. The 1/4-mile layout became a popular venue for legends car racing. The name "legends oval" was derived from this use. They have also seen use with go-karts, short track stock cars, and other lower disciplines. This idea was adopted by numerous tracks including Texas Motor Speedway, Atlanta Motor Speedway, Kentucky Speedway, Las Vegas Motor Speedway, and Iowa Speedway which has a 1/8 mile version. Perhaps the most unusual concentric oval facility is Dover Speedway-Dover Downs. The one-mile oval track encompasses a 0.625-mile harness racing track inside. By Banking / Superelevation Oval tracks usually have slope in both straight and in curves, but the slope on the straights is less, circuits without any slope are rare to find, low-slope are usually old or small tracks, high gradient are more common in new circuits. Circuits like Milwaukee Mile and Indianapolis Motor Speedway are approximately 9° tilt in curves are considered low slope, superspeedways like Talladega have up to 33° of tilt in curves, Daytona has up to 32°, both are considered high inclination. Charlotte and Dover are the intermediate with the highest bank, 24° tilt. Bristol is the short oval with up to 36° (later cut to 26° to 28°). By Surface Track surfaces can be dirt, concrete, asphalt, or a combination of concrete and asphalt. Some ovals in the early twentieth century had wood surfaces. Indianapolis Motor Speedway's track surface used to be made entirely of bricks, and today, 3 feet (0.91 m), or one yard, of original bricks remain exposed at the start-finish line. Each was hand laid over a 2-inch (51 mm) cushion of sand, then leveled and the gaps