Driving in tropical rain is pretty dangerous. The drops can be very big and it is often the case that you have to stop and sit it out.
This is usually caused when the wipers can't clear the screen quickly enough because the big drops form a very uneven film on the windscreen. The distortion of
forward vision out of the car can be quite severe.
The Water Blaster is a wall of ultrasound that disrupts the surface tension of the drops, allowing the vehicle's slipstream to push the finer droplets up and over the moving car, while they are still well clear of the windscreen surface. The windscreen wipers then have an even chance of doing their job, in even the heaviest rain.
There was some work done on water surface tension disruption, in 1978, by a scientist named Nyborg, but he was looking at the potential for ultrasonic frequencies to induce lung tissue damage, rather than practical applications in hydraulics. Ultrasound is sometimes used to atomise water in commercial humidifiers.