The law of cars (theory)

The law of cars is a theoretical law that notes that every time a pedestrians intends to cross a road or is about to cross a road, regardless of location (whether a dead end or a cul-de-sac) or time (whether 3am or 12 noon) a car must mandatorily appear to impede progress of the intending to cross pedestrian (this might be the flip side to the law of pedestrians).

Possible reasons
Unlike the law of pedestrians, which can be explained by high-intensity urban environment, the law of cars is much more difficult to explain as it's much broader. Conditions successfully tested include during early morning (3am) and dead-ends, all of which generally resulted in the law of cars occurring.

It's worth noting that the law of pedestrians is associated with the intention to cross and not the act of crossing itself (which would likely result in injury). It's effects could be considered akin to the Truman show in that, regardless of time or place, to make the act of crossing seem interesting, a car must mandatorily appear.

Related
See also:

The law of pedestrians (theory).