Video here.
What could be possible reasons? Highway seems to be in U.S .
Magnetized rebar.
It could also be something natural like an iron ore deposit in the area. Magnetism was discovered by folks who were playing around with naturally formed magnetic rocks. Google “magnetite” and “lodestone” for more info.
First of all, that’s not a straight highway: You can see the twists and turns ahead of the car. Second, it could also be fairly easily staged (not saying that it is, necessarily, just that it could be) by someone just off camera with a strong magnet.