Minefields right next to the road beyond that point. Roadblocks probably put by Militech personnel to prevent patrols from blowing themselves up. Probably nothing to patrol out there, too. There is some shards in the game about Militech wishing to expand their sphere of influence further from the Night City, to push back wraiths deep and far into the desert, but i understand this push is not any much done "yet" by the time we play.
That road leads to one of the Night City-NorCal border checkpoints, the Interstate 5 (I-5) freeway, (fictional) Stateline town and Fresno. If I had to guess, I'd say that roadblock is part of a unfinished cutcontent or a future DLC location (or both). 
