Halo requires 'London bus' Formula 1 car strengthening

Adapting the chassis to take the halo, which will be introduced this season, has proved to be a big task for F1 teams.

Williams chief technical officer Paddy Lowe has said integrating the halo was proving more challenging than dealing with any aerodynamic impact the device will have.

Speaking in a video released by Mercedes, Allison said adopting the halo had been "a significant challenge" for the world champion outfit.

"This is not a light piece of work, it is several kilos of titanium that needs to be put in the car," he said.

"There are changes that we needed to do to accommodate it to ensure the overall car would still stay below the weight limit.

"It's also not light because it takes really high loads.

"We had to strengthen the design of the chassis so it would be able to take roughly the weight of a London double decker bus sitting on top of the halo.

"We needed to make sure it would be strong enough to withstand the type of event it was designed to protect the driver against."

Allison said he expected the halo to evolve in the coming years as teams look to minimise the negative aerodynamic impact while also improving the aesthetics.

"This round tube is quite bad aerodynamically so we're all permitted to modify the halo in a way which will be individual for each team," he said.

"We're permitted to fit an aerodynamic fairing around it, which gives us a certain amount of scope to mitigate the effect it has on the aerodynamics of the car.

"What we're aiming to do is ensure the wake of the halo does not affect the smooth running and performance of the engine so we make sure the wake of the halo does not get ingested by the engine.

"We also make sure it is designed so that it doesn't damage the behaviour of the rear wing.

"This is the first generation head protection that goes up, over and around the driver's head. But it won't be the last.

"Nothing in F1 stands still for long. We will all be taking this first go and trying to improve it, trying to make sure the safety gets better but also the aesthetics.

"It's bit of an acquired taste and we're still acquiring it and everyone else too but I'm sure there are things we can do in coming seasons to make it also look nicer.

"The imperative to look after the driver safety and our desire to give us cars that are going to set the pulse racing aesthetically will see us continue to develop this concept in the seasons to come."