Saturday, July 11, 2020

Highways West of St. George

One of the most interesting segments of interstate highway today is the portion of I-15 through the Virgin River Gorge - the canyon on the Virgin River between St George, Utah and Littlefield, Arizona. But something a lot of people don't realize is that before the interstates were built, there was simply no road through the gorge. The previous highway connecting the two places took a major detour to the northwest, through the Beaver Dam Mountains.

The highway running northwest from St. George was first added to the state highway system in 1910, but it only went as far as Shem - essentially, that is at the modern Old 91/Gunlock Road split. The state highway would be extended southwest towards Littlefield in 1916. This highway was part of the Arrowhead Trail, an early auto trail that ran from Los Angeles to Salt Lake City.

When numbers were assigned to some of the more important state routes in the early 1920s, the Arrowhead Trail became part of SR 1. And when the US Highway system was approved in 1926, it became US 91. Here's a map from the time showing those designations:

Rand McNally (Utah), 1926.

From downtown St. George, the route proceeded north on Main Street, then turned to the northwest on Diagonal Street. It then continued west along what is now Sunset Boulevard, Santa Clara Drive, and Old Highway 91 to the Arizona line.

By 1940, US 91 had been moved to a new alignment in the St. George area. Rather than following Main and Diagonal Streets, 91 now followed St George Blvd and a new road along the northwest side of downtown, Bluff Street.

Here's a US Census map from then - note the old Diagonal Street alignment. Also notice how SR 18 heads north from the city along a much different roadway than it does now - the modern road north from what's now Bluff and Sunset wouldn't be built until at least a few years later.

1940, US Census.

Various routes would come and go in the St George area over the next 30 years, but for this post we'll only talk about two: SR 300 (which we'll come back to later) and SR 34. SR 34 was created in 1964, with the following description:
From Interstate Route 15 south of St. George northerly to Route 1 in St. George.
That was a proposed southward extension of Bluff Street, which would follow the southwestern side of downtown St. George and end at an interchange at the proposed I-15. However, in 1969, the segment of US 91 on St George Blvd was also transferred from SR 1 to SR 34. So although only half of it existed at the time, the plan was for SR 34 to represent the entire St George business loop.

In June 1971, UDOT received approval from AASHTO to move US 91 onto I-15. However, this would not have had any effect until 1973, when I-15 finally opened from St George through the Virgin River Gorge.

SR 1 was moved to I-15 upon its completion, which left the question of what to do with the portion of original SR 1 between the Arizona line near Littlefield and St George Blvd. Almost all of it was decommissioned -- the entire section from Arizona through Sunset Blvd was returned to local jurisdiction. The portion south of Shivwits is now signed as Washington County Route 91.

That left the short segment on Bluff between Sunset and St George Blvd, which became a southern extension of SR 18. 18 was further extended over 34 to the south St George interchange on I-15, cutting 34 back to only its portion on St George Blvd.

Those changes occurred in 1974, and were approved by the legislature the next year. In addition, in June 1974, AASHTO officially eliminated US 91 from this area. All this is reflected on the 1980 USGS map:

USGS (St. George), 1980.

Notice how both St George interchanges were originally trumpets, yet neither of them are today. The one at the east end of SR 34 was reconstructed in 1991 into a diamond...

Google Earth, 1993.

... but was further reconstructed in 2013 into a diverging diamond:

Google Earth, 2015.

The 1991 reconstruction was more interesting because it actually required a route redefinition: the east end of SR 34 was extended slightly from I-15 to River Road (the north-south road at far right of the satellite images above). Even though it's short, this extension is remarkably well signed today.

No, I didn't forget SR 300. Let's go back to that...

SR 300 was created in 1972. As its number might suggest, it served a state institution - in this case, Snow Canyon State Park. SR 300 consisted of the main Snow Canyon Road, from the south boundary north through the park to a junction with SR 18. Although some of these park roads aren't signed, this one probably was given that it appeared on the USGS's maps:

USGS (St George), 1980.

It lasted unchanged until 1991. That year, in exchange for the deletion of SR 281 (which had served Dixie State College), several roads in St. George's northwestern suburbs were added as a new SR 8. The new route would begin at Bluff Street (SR 18) and head northwest on old Highway 91 along Sunset Blvd and Santa Clara Drive through Santa Clara. Then, it would turn north on 200 East (Red Mountain Blvd) to Ivins, where it would turn east on Center Street and go on to absorb SR 300 through Snow Canyon.

Here's a map from the relevant transportation commission resolution. The dotted red line represents what was already SR 300, while the yellow highlighted road is the planned new SR 8:

Utah Transportation Commission (SR-8 Resolution), 1991.

But here's the weird part: none of that actually became SR 8 at the time. The 1991 resolution creating SR 8 contained two pages of upgrades that St George, Santa Clara, and Ivins cities would have to make before UDOT would take over the road. As a result, the legislature did not actuate the new route, and SR 300 continued to be used for the Snow Canyon State Park road.

By 1996, the necessary upgrades had been completed between the eastern terminus at Bluff Street and Dixie Downs Road, about a mile west. As a result, that portion of SR 8 was finally actuated by the state legislature. However, the portions through Santa Clara, Ivins and far western St. George remained unactuated.

1996 was also when SR 300 was finally renumbered as previously proposed, so SR 8 existed as a discontinuous roadway with a gap through Santa Clara and Ivins. But that didn't last long: a few years later, the new Resource Management Plan for the state park called for some significant changes to Snow Canyon Road, including adding entrance booths, parking lots, and converting part of the road to one-way traffic. That was deemed to be inconsistent with the criteria for a state highway, so in 1999, all of SR 8 within the state park was turned over to the state Division of Parks and Recreation.

The route hasn't changed since then. When the legislative description was updated in 2000, it read:
From Route 18 in St. George on Sunset Boulevard to Dixie Downs Road. Portion not Actuated.
In 2005, the "portion not actuated" label was removed. I'm not sure how to interpret that, or if it means anything - does that mean UDOT no longer plans on taking over the remainder of the originally proposed SR 8? Or have the cities just not completed their upgrades yet - or do they even plan to? Only time will tell.

Unrelated to the routes: one thing I noticed when researching this post is that the intersection between Sunset Blvd, Bluff Street, and Diagonal Street has been reconfigured a not insignificant amount of times. I'll go through a brief history of each step here:

1. Diagonal and Sunset were originally one road, carrying US 91.

2. Bluff Street was built south of Sunset by 1940, and Valley View had been built going off to the southwest from that intersection. Bluff and Sunset were probably one road, and Diagonal/Valley View another, but it's impossible to know for sure.

1940, US Census.

3. By 1953, Bluff Street had been built north of St George, junctioning Sunset just south of Diagonal. The junction was set up so that Sunset and south Bluff were the mainline. Diagonal went west through both Bluff and Sunset, becoming Valley View Drive (unpaved in the image below, but paved after 1960).

Historic Aerials, 1953.

4. Around 1970, the intersection was split up. Valley View was shifted northwest to end directly at Sunset, while Diagonal completely lost its connections to Sunset and Valley View:

Historic Aerials, 1973.
5. Bluff Street became the through movement in the 1980s, with a signalized seagull intersection at Sunset. Diagonal became a RIRO off of northbound Bluff south of Sunset - previously, it had intersected Bluff north of Sunset:

Google Earth, 2017.

6. In 2018, Sunset-Bluff south once again became the mainline. No imagery yet (that I have access to, anyways), but here's a screenshot from Google Maps:

Google Maps, 2020.

Route Photos

SR 8

SR 34

Sorry, no photos for these least for now.

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