Side Of The Road

Context would help. General location (state, country, etc)? What kind of road? Were you near any other car infrastructure? Are the directionals pointing at anything informative?

I suspect the box facing down is some kind of short range antenna. Like for reading toll passes kind of thing, though I doubt this is that. The directionals first reminded me of like IR sensors for like emergency vehicle signalling, but you'd normally see that on a traffic light.