Four classes of sports cars compete within the American Le Mans Series for overall wins and the overall championship, as well as class victories and class championships. The classes are easily identified by a color-coded race position lights on the cars as well as matching car numbers as noted below.

LMP1 (Le Mans Prototype - LMP - 1) Red position lights and red car numbers
Purpose-built race cars such as the Audi R10, Lola B06/10 and Zytek 04S Minimum weight of 2,040 lbs Speeds of 200+ mph 600 - 700 horsepower
LMP2 (Le Mans Prototype - LMP - 2) Blue position lights and blue car numbers
Purpose-built race cars such as the Lola B05/40, Courage C65 and Porsche RS Spyder Minimum weight of 1,708 lbs Speeds of 180 – 200 mph 500 - 550 horsepower
GT1 (Grand Touring - GT - 1) Green position lights and green car numbers
Production-based, two-wheel drive race car such as the Aston Martin DBR9, Chevrolet Corvette C6-R and Ferrari 550 Minimum weight of 2,480 lbs Speeds of 180 - 195 mph 600 - 650 horsepower
GT2 (Grand Touring - GT - 2) Yellow position lights and yellow car numbers
Production-based, two-wheel drive race cars such as BMW M3, Ferrari 430 and Porsche 911 GT3 RSR Minimum weight of 2,480 lbs Speeds up to 180 mph 450 - 500 horsepower

The Leader Light System signals, via lights on the cars, the top three positioned cars in each class.
One light for the leader, two lights for second place, three lights for third place.