The facility's main entrance has a metal roof guard house to permit traffic to and from the prison.
The bridge is narrow, only wide enough to permit traffic to pass in one direction at a time.
It permits outbound traffic all the time, which is why it still makes sense to have a personal firewall running on the computer.
A ford permits vehicular traffic to cross a waterway with wet wheels.
Detroit area freeways are sometimes sunken below ground level to permit local traffic to pass over the freeway.
This allows time for the lane to clear of traffic before a green arrow permits traffic in the reversed direction.
That shift would permit traffic on Liberty Street to run in both directions.
The garage fronted on a narrow street that permitted westbound traffic only.
A. It's a way of permitting traffic to turn earlier than at the actual intersection.
Guard against falls by arranging furniture to permit unobstructed traffic through rooms.