Union City, California Roadblocks

I was traveling southeast on Alvarado Niles and saw a police roadblock for vehicles traveling the other direction. This was on a Sunday afternoon in the vicinity of Decoto Rd. Locals later informed me that this thoroughfare was a common DWI checkpoint location on weekends. If our government truly cared about preventing alcohol-related accidents, shouldn’t all vehicles have alcohol-sensing ignition systems (that could be overridden in absolute life/death emergency)?