You can always measure a racing game's graphics by its weather effects. Project CARS delivers very well indeed on that front, boasting dynamic weather with some utterly convincing spray effects. You even have to manually turn on the wipers.
DriveClub gives it a serious run for its money, though, as Evolution went the extra mile by adding water droplet movement physics so that the water dynamically sloshed around the windscreen as you drove.
Not to be outdone, Slightly Mad are already working on improving the rain effects in Project CARS, and will also be adding physics-based water droplet movement to match DriveClub as shown in a couple of work-in-progress developer videos.
https://youtube.com/watch?v=U8ybUufKSJE%3Frel%3D0
As such, Slightly Mad Studios are said to be working on optimising the weather effects so that the new water droplet physics won't have an adverse effect on the performance.
https://youtube.com/watch?v=MegtkiOmpHU%3Frel%3D0
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