Could Moving Cars Help Measure Rainfall?

A recent study looks at how some cars may be helpful in tracking the amount of rainfall.

"If moving cars could be used to measure rainfall the network density could be improved dramatically," explains project-leader Uwe Haberlandt, who says the idea for RainCars emerged during a brainstorming session between geoinformatics researchers and hydrologists, according to a press release.

The study authors note that over 40 million cars in Germany may be able to successfully track the amount of rainfall with a rain machine that measures liquid via wiper speed.

In one of set of experiments, participants in the cars adjusted the wiper speed mutually, depending on the windscreen visibility.

"The experiments have shown that the front visibility is a good indicator for rainfall intensity," said Ehsan Rabiei, Haberlandt's collaborator and the paper's lead author, via a press release. However, researchers note that the measurements via the windshield wipers may not always be so accurate as individuals can adjust the speed of the wiper.

Another set of experiments had researchers use the rain machine to test optical sensors that are installed in many modern car's automatic wipers. They use a system of infrared laser beams in order to detect when drops of rain accumulate on the surface of the device.

"The optical sensors measure the rain on the windshield in a more direct and continuous manner so, currently, they would be the better choice for rain sensors in cars," said Haberlandt, via the release.

The team also tested the effects of car movement on the measurements by placing the sensors on a rotating device and stimulating the speed of the car while under a rain stimulator.

However, Rabiei emphasizes that speed is not the only thing that can alter rain measurements. "Our experiments so far were carried out in an ideal and controlled environment. In nature there are external effects like wind, spray from other cars or shielding trees that can affect the readings, and rainfall characteristics are different from the rain simulator."

More information regarding the study can be found here.