Texas Interstate 35 that runs North and South. Appears to be the section between the border town Nuevo Laredo and San Antonio.
It doesn’t look “random”. I think I saw some permanent structures and fixtures in that video. So, is this an illegal checkpoint? If a guy is travelling from one US town to another I would think it technically is. But I’m no expert.
A lot of people don’t know this, but during the depression California had border crossings with other states. They would not let you in unless you had proof of a waiting job, California citizenship, etc.
This is I-8, the last CP is in East San Diego county. They are manned by the BP and have assistance from the CHP. Primary use is in alien smuggling and narcotic interdiction including the money involved. About 5-10 miles N of the border, in an area rife with smuggling of both kinds. Likely had a dog sniffing his car while he was waiting. The Ag CP he refers to is on the Az/Cal border, also on I-8. They ask if you have any fruits or other agriculture products with you.