Here is a photo of the North Portal of the Liberty Tunnels in 1924, shortly before opening. Note how the lanes veer off towards Arlington Boulevard. McCardle Roadway, descending from Mount Washington, had not yet been completed and all northbound traffic had to be routed to the right. Soon, after the completion of McCardle Roadway, a circular garden was installed and traffic flowed to the left and to the right.

The photo below shows the North Portal in 1928, showing the circular garden area at the entrance and exit. At that time the large circle was a nice addition and would soon contain a monument. The Liberty bridge had just opened, and traffic now moved in all directions. Soon vehicular traffic was on the increase, and the circle was made smaller. It became quite a nuisance and was eventually removed.

Only four years old in 1928, the white facade of the "tubes" already showed the effects of the sooty atmosphere of Pittsburgh at a time when steel mills were king.

Twelve years later, in 1940, after the circle was removed from the north portal entrance, Traffic Division officers watch as traffic passes. The traffic pattern may have changed for the better, but the smog is so thick that it partially obscures the view.