Only because it's apparently never been mentioned here, this is a page from the Washington County Historical Society about the original routing of US 91 through a two-lane tunnel between St. George and Washington:
http://wchsutah.org/roads/washington-tunnel.php
The deep cut in the mesa through which I-15 now travels -- and which presents a significant barrier to east-west movement between Washington and most of St. George -- was made sometime between 1948 and 1954. Before that, US 91 used the tunnel through the mesa. The tunnel still exists today but is used only for storage.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Fwchsutah.org%2Fphotos1%2Fwchs-01395.jpg&hash=a262f62e4a06a7162991301df59d8b2ec51fa959)
I thought of this because, when I-15 was expanded a while back, the cut through the mesa now carries a staggering (at least by southern Utah standards) 15 lanes of traffic between St. George and Washington: Six lanes on I-15, four on Red Cliffs Drive, and five more on Red Hills Parkway. Here's a recent Street View looking through the cut:
(https://i.imgur.com/yVbESMh.png)
Very interesting, thanks! I had never heard about that tunnel.
Quote from: usends on March 14, 2019, 08:58:59 PM
Very interesting, thanks! I had never heard about that tunnel.
This exactly. It makes sense too; Middleton Dr lines up perfectly with Telegraph Rd across the freeway, which we already knew was the old routing of US 91.
In addition, Historic Aerials confirms the modern roadcut did not exist in 1953.
Quote from: usends on March 14, 2019, 08:58:59 PM
Very interesting, thanks! I had never heard about that tunnel.
Me neither. I look forward to checking this area out next time I'm in St. George.
Thanks Max.