Don't we have the technology to just about automate the whole thing?

Drive to border, if your suspicious go to giant car wash, drive up to the line, car is hooked in, get out of car, vehicle is scanned and x rayed while you walk across border hallway and talk to greeters border agents. If nothings wrong get back into car and drive into other country.

They can detect explosive compounds (firearms/ammo/bomb), drugs, and people in the trunk very easily now with technology.