Sonoma Raceway, formerly Sears Point Raceway and Infineon Raceway is a 2.52-mile (4.06 km) road course and drag strip located in Sonoma, California. The road course features 12 turns on a hilly course with 160 feet (49 m) of total elevation change. It is host to one of only two NASCAR Sprint Cup Series races each year that are run on road courses (the other being Watkins Glen International in Watkins Glen, New York). It is also host to the Verizon IndyCar Series and several other auto races and motorcycle races such as the American Federation of Motorcyclists series.
Sonoma Raceway continues to host amateur, or club racing events which may or may not be open to the general public. The largest such car club is the Sports Car Club of America.
Variations of Sonoma’s circuits are often used. Motorcycles use a 2.22 miles (3.57 km), 12-turn course. It is based on the full layout, and does not include the Chute. This layout, opened in 2003, skips the later section of the Esses (8A and 9) and the run from Turn 10 to Turn 11 (the hairpin), using instead Turn 11a as Turn 11 has no runoff. This hairpin is located just past the drag strip control tower and offers a fairly straight run to the start-finish line.
When the Pirelli World Challenge returned to Infineon Raceway in 2011, the modified course was used (as the series doubleheader was acting as a support event for the Indy race). During the broadcast, it was explained that the Indy course skips much of the high-speed esses due to the curving section from Turn 9 to 10 ending with no runoff, especially on the outside of the curved section (bordered by the drag strip), and precariously little runoff in the high-speed Turn 10.
Another factor in removing the hairpin is the fact that the turn is only visible from the garages or the bleachers behind the esses. This is due to grandstands built along the front straight that serve also as the drag strip’s grandstands.
For the 2012 IndyCar race, the course was modified again. The Magny Cours-style hairpin in Turn 7 was used to create a passing zone. Turn 9A (the chicane similar to Spa’s new Bus Stop) is being widened by ten feet (~3 meters) to allow for more room. A new Turn 11B has been made, moving further past the drag strip tower (Motorcycle Turn 11), being lengthened by 200 feet (~61 meters) to create a passing zone (it is located just before the race logos painted in Turn 11), and is located where the drag strip staging area is located.