PIV (Particle Image Velocimetry) is not a new technique for understanding the aerodynamic drag of a vehicle, but deploying it in the uniquely repeatable environment of Catesby Tunnel is. This ground-breaking application involves seeding the test section with neutrally buoyant helium soap bubbles, shining a powerful laser through them and capturing the movement via multiple high-speed cameras. Improving the aerodynamics of a vehicle in this novel way paves the way for improving the range of EVs and reducing the size and weight of batteries which are crucial to the decarbonisation of the automotive industry. In motorsport the possibilities to improve performance are endless. Minor changes in set up, body work panels and even wheels can be scrutinised with greater confidence than ever before.