Hard core 3-second freeway drafter here.

70 mph = 102.667 ft/sec
1 Mirage car length = 12.45 ft

7 car length gap = 87.15 ft = 0.85 sec
10 car length gap = 124.5 ft = 1.21 sec
24.74 car length gap = 308 ft = 3.0 sec