Thunderhill Raceway Park is a motorsport complex located in northern California, an hour and a half drive away from Sacramento. It is without a doubt the most versatile racing facility in America, having several possible layouts such as 2-mile, 3-mile, and 5-mile road courses, as well as a 315’ x 550’ skidpad and a 662’ x 363’ autocross pad. Thunderhill follows designs planned by Steve Crawford, who envisioned building two independent road courses next to one another: a 2.87 miles East track and a West track with 1.99 miles. The 5-mile combination of both racetracks forms the longest road course in the United States.
Thunderhill East started operations in 1993, adding the West course in 1995. The East track takes advantage of the natural elevation changes in the field, having 15 exhilarating turns where drivers often lose sight of what is coming right ahead of them. The straight segments are ample and long enough to allow easy passing between drivers. Thunderhill West is more technical, requiring top driving skills to leverage momentum while taking its ten turns, which come in quick succession. The 25 Hours of Thunderhill, the most famous event of the circuit and longest endurance racing competition in America, takes place on the combined 5-mile road course since 2003.
The standard direction for racing in Thunderhill West is counterclockwise, but it is also possible to race it in the clockwise direction. For the CW variation, the average speed is a little slower, with 80 mph, compared to 82 mph when running CCW. Average lap times are also minor, with 1:29.364 for the CW direction versus 1:29.364 in the CCW one. Nevertheless, the challenging and enjoyable ride more than compensate for the slower time marks.