Ideas que utilizan imanes

Autonomous Tech with in-Road Magnets

Existing technologies including GPS and forward-facing cameras have limitations. Physical obstacles can block their scanning abilities as can adverse weather. Magnets embedded right in the road have no such disadvantages.
The magnets are round and measure about 40 by 15 millimeters – roughly an inch and a half by half an inch. They’re safely buried 200 millimeters (approximately eight inches) below the road surface where they are totally safe from weather or damage.
These magnets create an invisible railway that guides autonomous vehicles. Accuracy is pretty impressive, with variation of less than one decimeter, which is about four inches. Beyond self-driving cars these embedded magnets can help other vehicles as well. For instance, they can guide plow trucks more accurately in adverse conditions so they don't damage things buried in snow.