After persistent rain prevented the 2021 Belgian Grand Prix from concluding any racing laps, the wheel arch or "mudguard" idea was born. In order to ensure that track activity can take place under extremely wet conditions, the concept is that every car will have the wheel arches fitted. The "mudguards" will remain on the cars even if the track dries, freeing teams from the responsibility of removing the device during a pitstop.

Following the World Motor Sport Council meeting in Abu Dhabi in November of last year, the FIA presented its plans for the testing.
The FIA said, “Driver feedback has suggested that there has been reduced visibility in extremely wet conditions with this latest generation of cars, which is a key determinant on starting, or needing to suspend sessions.

“Therefore, the FIA commenced a study to define a package of parts aiming to suppress the spray generated when running in wet conditions.”

The test took place at the Silverstone Circuit on July 13, 2023, post the British GP. Parts of the circuit were artificially made wet to simulate low visibility conditions.

To enable a direct comparison, the Mercedes’ test driver Mick Schumacher had the arches while the McLaren driver Oscar Piastri did not, with the cars running simultaneously and independently. The gathering of aero data to understand the effect of the arches was another goal of the testing.

But German automobile magazine Auto Motor und Sport reported the testing to be complete "failure" with their correspondent Andreas Haupt writing, “And according to observers, the aesthetics of the fenders left a lot to be desired."

While preparing for the Hungarian Grand Prix, Andrew Shovlin, Mercedes trackside engineering director, said on the testing “I mean, there's more work to do on them." 

"They're not ready to be moved into production and regulation at the moment. There's definitely work to do."

Even while the devices lessen spray, according to Shovlin, "you still get a lot coming from the diffuser, in the way that the rear wing is pulling it up."

He further went on, "That's all very powerful,”

"But it was interesting first steps and we're providing the car and some bits to do that development.”

"It's the FIA's project to decide where that goes next and what happens in the future."