The circumference of a circle = 2 * radius * pi. On the straightaways, both lanes cover the same distance.
Talladega turns have radius = 1100 feet. Assume this is to the double yellow line at the bottom...
Inside Circumference = 2 * 1100 * 3.1416 = 6,911.5 feet
For the second lane, I'd assume the radius is about 15 feet greater...
Outside Circumference = 2 * 1115 * 3.1416 = 7,005.8 feet
Difference = 7,005.8 - 6,911.5 = 94.3 feet! Before I did that math, there is no way I'd have guessed that much.