Road blocks, or check points? Closing the road is not equivalent to a slowdown for a BG Check. Closing all but one lane, and checking the ID of every driver is closer
It's unclear to me what distinction you are drawing here. Check points/road blocks, everywhere I've seen them, are basically the same thing. Police officers identify a section of road, then stop every driver who comes along (though this is frequently only drivers going in one particular direction - in other words, they might stop all southbound drivers but allow all northbound traffic through). Whether you call it a road block or a check point, the driver is still stopped and the police officer free to question you at his leisure.