A Champ Car is a single-seat (commonly called open-wheel in the US) racing car. For much of their history Champ Cars have been similar to Formula One cars, although there have traditionally been several key differences between the two. Over the years, Champ Cars race schedule included high speed oval tracks. The increased stress and speed of these tracks mean that the cars tended to be heavier and have longer wheelbases than F1 cars (increasing stability but decreasing agility). In 2007, there are no oval tracks on the schedule. When the weight of the driver is factored in, a Champ Car weighs over 30% more than a Formula One Car. The minimum weight for a Champ Car is adjusted from 1,575 lbs based on the weight of the driver compared to the field average; with the driver included, all cars have a minimum weight of 1741 lbs. A Champ Car piloted by 195 lb Paul Tracy (the heaviest driver in the series and 29 lbs heavier than the field average) must weigh at least 1,546 lbs when empty. The minimum weight of a Formula One Car, including the driver, is 605 kg (1,334 lbs). This difference of 407 lbs (184.6 kg) is just over 30% of the F1 car's weight.