The car under the bridge

Part of my everyday commute includes a short walk under a freeway, four contiguous blocks of concrete with tonnes of load on it, what if it came crashing down? But that's not what I've been pondering on! I almost always notice a lone car parked in the dark shadows on the two+ lane road with someone in the passenger seat ... I ponder as to where the driver is, what conspiracy he is hatching that makes him want to park his ford explorer* day after day under the bridge. What about his partner who sits idle, waiting for him? Puffing along the way or waiting for his guardian angel?

*Vivid imagination could have led to distortion of facts