IndyCar racers use LEDs to show their positions in real-time
 

It's sometimes hard to keep track of positions in an IndyCar race, especially if you're in the stands and don't have the luxury of a broadcaster or data stream to point things out. Never fear, though: as of this weekend, the league's cars are carry...

http://www.engadget.com/2015/08/02/i...cid%3Drss_semi