Curves matter less than tires at legal speeds, yet the tunnel still decides a coupe’s fate. Air drag only overtakes rolling resistance as velocity climbs, because drag scales with the square of speed and power demand with the cube, while hysteresis losses in rubber stay almost linear with load and speed.
Designers keep chasing airflow because physics is only half the story. At modest speeds, a lower drag coefficient and smaller frontal area still trim fuel or battery use, cut noise generated by turbulent boundary layers, and stabilize yaw behavior in crosswinds, so a sleek coupe feels planted instead of vague.
The tunnel also doubles as a branding lab. A specific pressure distribution over the body lets stylists lock in a signature roofline without triggering flow separation, while active aero devices and underbody diffusers are tuned for future high-speed or performance variants, long before drivers ever reach those conditions on a track.
