Ok so let's try a few easy numbers to see if we have an issue or not.

Suppose we have a gasoline powered car that get 20 MPG. That's very realistic I think. It would produce a gallon of water for every 20 miles traveled. So if one were to scatter the ice crystals from one gallon of gas over a 20 mile track could that cause any safety problems? I don't think so.

I understand that to produce the same power one needs to consume about four times as much hydrogen gas as gasoline liquid by volume.

Let's not use the 4:1 ratio. Let's go to the extreme.

Suppose we have a hydrogen powered car that gets only 1/20th the MPG of the gas car. That would mean putting out a gallon of water every mile. So would it be a hazard if the ice crystals from a gallon of water were uniformly distributed over a 1 mile strip? Again, I don't think so.

This is totally off the cuff so please poke holes in my reasoning.