You've got a good start there. The clouds are very nice!
Some things:
Rain doesn't fall in the same direction all the time. A few degrees variation between the drops will add some realism.
Spray is a tricky thing to pull off. A lot of people go about it differently. Look up cars driving in the rain on google. Really study the pictures to get a good idea of what it would look like.
And don't forget the trails the tires leave behind. Add a stripe behind the tires that is lighter than the road to really sell the effect.
But since it is just starting to rain in your picture, these things should be subtle.
👍