How does NASCAR judge a photo finish? Here's the process

By Bob Pockrass
Published

LAS VEGAS — When three cars are separated by seven-thousandths of a second at the finish line, that would be the definition of a "photo finish."

So how does NASCAR rule on a photo finish like it had Sunday night at Atlanta Motor Speedway when Daniel Suarez finished 0.003 seconds ahead of Ryan Blaney and 0.007 seconds ahead of Kyle Busch?

NASCAR has two high-speed photo (not video) cameras focused on the start-finish line. One of the cameras is located a little bit higher than the other because if there was just one camera, there is a remote chance it could be blocked or malfunction.

Typically, the cameras are situated on pit road (NASCAR cordons off the area with a big "do not enter" sign), but sometimes they have to be placed scaffolds or above garages or infield suites depending on the race track. The cameras are kept in a case separate from other cameras NASCAR might use for the weekend for integrity purposes.

The cameras are capable of taking photos at speeds of 3,000 to 20,000 per second but usually end up taking them at 6,000 to 8,000 frames per second. The cameras are motion-generated so anytime a car (or sometimes a butterfly or piece of trash) goes across the finish line, it starts taking the photos, according to NASCAR's chief scorer Kyle McKinney.

The photos are then used to form a still photograph as they cross, using a red line to designate the start-finish line, which is the leading edge of the yellow (or other color) line painted on the track, typically in the middle of some track or checkered flag artwork. There is no artificial intelligence used.

An official in NASCAR's timing and scoring technology center truck that is typically located in the broadcast compound (NASCAR's pit-road officiating system truck also is in the compound) can call up the photos immediately to help NASCAR decide not just the winner of the race but any order of finish when it comes to the end of the stage or the end of the race. Those in the officials booth who make the decisions on cautions and penalties can also take a look if they want.

The cameras are also often used during a race to determine a lap leader. If the photo finish of the race shows a dead heat and NASCAR can't determine the leader at the line, the driver among those tied who has led the most laps is declared the winner of the race. If the same, then the driver among those tied who finishes the most laps in second is declared the winner and so on.

The cameras are similar to ones used in other sports,  such as horse racing and the Olympics.

It takes about an hour or so for NASCAR to set up the cameras each week.

Bob Pockrass covers NASCAR for FOX Sports. He has spent decades covering motorsports, including over 30 Daytona 500s, with stints at ESPN, Sporting News, NASCAR Scene magazine and The (Daytona Beach) News-Journal. Follow him on Twitter @bobpockrass.