Watching this commerical... couple is late for something... guy is
driving through construction zones, a tunnel, and then he's closing in on
what looked like a bus with no other vehicles on the road and an empty
left lane, getting dangerously close, and this red light starts flashing
on the dash and there is an alert sound. He swerves left and avoids
hitting the bus.

It would seem they've added an invisible bus detector to their cars.