The sound of the rain saves lives
Problem: Modern cars are filled up with assisting systems that we almost never use or can easily do without. Night vision camera's, head-up displays, traffic sign recognition, 360 degrees overview, and so on, and so on.
However, aquaplaning kills many people each year. Especially people who are unaware often loose control of their cars and get hurt badly.
Still the solution is rather simple. Deep puddles make a completely other sound then shallow ones and are never stand-alones. By listening to this sound the car can estimate the danger and inform the driver. He or she can then take action.
Simple technology, easy to install, vital information (especially with the climate changes), a "puddle" sensor should be compulsory on every car.