Aero Research Partners (Arp) carry out aerodynamic tests with the vehicles moving inside the Catesby Tunnel. The 'environment' is free of disturbing elements such as the wind found on the tracks for dynamic tests and is more realistic than those found in wind tunnels.
The measurements on aerodynamic resistance which are carried out using the 2.7 km long strip of asphalt "are perfectly aligned with those of traditional wind tunnels" but with the crucial addition that the vehicle is evaluated in real operating conditions.