Question: what is the average speed of a nascar car

title: Monster Energy NASCAR Cup Series
text: Race speeds vary widely depending on the track . The fastest track is Talladega Superspeedway , where the record average speed is 188.354 mph ( 303.126 km / h ) and the record qualifying lap is 212.809 mph ( 342.483 km / h ) , set by Bill Elliott in 1987 . The record stands unlikely to be broken , as restrictor plates were made mandatory at superspeedways in 1988 to reduce speeds . The slowest tracks are Sonoma Raceway , a road course with a record average speed of only 83.6 mph ( 134.5 km / h ) and a record qualifying lap of 99.3 mph ( 159.8 km / h ) , and Martinsville Speedway , a short , nearly flat `` paper clip '' oval , with a record average speed of 82.2 mph ( 132.3 km / h ) and a record qualifying lap of 99.9 mph ( 160.8 km / h ) . The average speed of a race is determined by dividing the winner 's race time ( from the waving of the green flag to the waving of the checkered flag , including laps spent under caution ) by the distance of the race . Time elapsed during red flag periods is not included in the calculation of the average speed . 

Answer: answer: Race speeds vary widely depending on the track . The fastest track is Talladega Superspeedway , where the record average speed is 188.354 mph ( 303.126 km / h ) and the record qualifying lap is 212.809 mph ( 342.483 km / h ) , set by Bill Elliott in 1987 .The slowest tracks are Sonoma Raceway , a road course with a record average speed of only 83.6 mph ( 134.5 km / h ) and Martinsville Speedway , a short , nearly flat `` paper clip '' oval , with a record average speed of 82.2 mph ( 132.3 km / h ).