Downforce

Downforce is a measure of how much vertical aerodynamicAerodynamics is the science of controlling how the air behaves as the car cuts through it at speed. F1 cars... There's more... load is created by a Formula 1Formula 1 is the pinnacle of open-wheel,  single-seater car racing and arguably the highest level of any motorsport globally. Also... There's more... car’s aerodynamic surfaces.

The same principle as an aeroplane wing, only up the other way.

As the car moves forward, it splits the air particles with some going over the car and some going under. The floorThe floor or the undertray (underbody) is the highly complex component that tunnels air under the car creating downforce. This... There's more... is designed to create a longer flow path so the air particles accelerate to get to the rear of the car at the same time as those travelling over the car, creating low pressure that pushes the car down towards the road surface. 

The payoff for downforce is dragDrag is the resistance caused by air hitting a solid object as it is propelled forward. When the solid object... There's more..., which is why F1F1 is the pinnacle of open wheel,  single seater car racing and arguably the highest level of any motorsport globally.... There's more... cars utilise the DRSThe Drag Reduction System (DRS), is designed to do exactly what it says, reduce drag, resulting in the recipient gaining... There's more... on high-speed straights. 

At high speed, the downforce created by an F1 car will be far in excess of its weight, so in theory, this would allow it to drive upsidedown along the ceiling of a tunnel.