I-15 History

[Mergingtraffic]

Utah seems proactive in their expansion of roadways.  Anybody know the history of construction of I-15 in the Salt Lake City area?  
How many lanes did the highway originally have? and what was added and when?

I remember seeing a story saying that I-15 was being expanded for the Olympic games in 2002.  Boy, if that was my home state they would just use extra buses instead of redoing the highway.   People seem more open to highway expansion out there.

[Sykotyk]

I wasn't out in Utah during the pre-Olympic days, but a lot of the interchanges were drastically rebuilt to handle the traffic and contain neat hieroglyphics on them denoting Olympic events, logos, etc. Mostly SPUI's and multi-lane on/off ramps. Mostly, today some interchanges are overbuilt with the abundance of multi-lane on/off ramps. But, someday it'll probably come in handy.

[kurumi]

Boy, if that was my home state they would just use extra buses instead of redoing the highway.   People seem more open to highway expansion out there.

I have to protest that unfair characterization of Connecticut roadbuilding! CT would do all sorts of things: replace signs, upgrade guardrail, milling and resurfacing, various safety improvements... but upgrade capacity, no.

[CL]

Okay, here's the hodgepodge of information I know about I-15 through Salt Lake City, as well as southern Davis County. I'll update this as I find out more.

Pages Ln (Farmington) - Beck St (North Salt Lake): 2 November 1960, three lanes each direction; I believe this is the first signed section of I-15
Beck St - 1000 North: October 1956; this is the earliest section of freeway in the state, initially signed as US-89/91
1000 North - 600 South: 30 October 1964, four lanes each direction
600 South - 3300 South (through I-80, US-40A/50A): 19 April 1965, three or four lanes
3300 South - 5300 South: 23 November 1966
5300 South - 12300 South: various dates between 1967 and 1971
12300 South - Utah County: 1970 or 1971

In 2001, a reconstruction project from 600 North to 10600 South was finished (112 city blocks of freeway). Four lanes in each direction, plus auxiliary lanes between interchanges.

In 2009, reconstruction projects from Beck Street to 600 North and from 10600 South to 12300 South widened those stretches of freeway to four lanes in each direction. So, the only original section of I-15 in Salt Lake City is from the Utah County line to 12300 South (not a very big distance), although lanes have been added to both sides of the original concrete pavement.

There you have it.

Mostly, today some interchanges are overbuilt with the abundance of multi-lane on/off ramps.

Drive through Salt Lake City during rush hour and you'll know that these on- and off-ramps are already overloaded.

[Sykotyk]

I've driven through SLC many times in rush hour. Not all of the SPUIs are full during rush hour. Sure, the I-15 corridor is horrid and in need of as many SPUIs as they can get. But, 201, 215, etc they're overbuilt. You don't overbuild an interchange just to handle gobs of traffic for two hours a day. That's just not economical. One place that could've used a simple SPUI was 201/Bangerter, but instead 201WB has 3 left turn lanes to Bangerter SB. Go figure. At least 5600 is currently adequate (although the south frontage road really could use slip ramps and lights rather than restricting which way you can turn.

[nexus73]

What is overbuilt today will be needed tomorrow is how I see UDOT's approach.  Their planning is timeframed to 2040 and they have the projects tiered in stages, with each stage being a decade (current, 20's, 30's).  The Wasatch Front is a highly urbanized area and it's only going to get more crowded with people and vehicles as time goes on.  Light rail and commuter rail projects of a large scale to cover the Wasatch Front are also being built.  Utah's looking forward long-term vision is to be congratulated IMO.

Rick

[CL]

But, 201, 215, etc they're overbuilt. You don't overbuild an interchange just to handle gobs of traffic for two hours a day. That's just not economical.

I don't know. Shouldn't that be the aim, to handle rush hour traffic effectively? If you're going by traffic counts at 11 am, then yes, our ramps are rather overbuilt.

One place that could've used a simple SPUI was 201/Bangerter, but instead 201WB has 3 left turn lanes to Bangerter SB. Go figure.

Agreed. That's why they're building a DDI at that interchange.

At least 5600 is currently adequate (although the south frontage road really could use slip ramps and lights rather than restricting which way you can turn.

Again, it's adequate if you're going by traffic at 11 am. That thing can back into the main flow of SR-201 as early as 4 pm (which is when rush hour is about an hour in in Salt Lake), simply due to the fact that the exit ramp is one lane until widening to two (one lane left turn only, the other left and right turn) just before the intersection at 5600 West.

I agree with Rick; all UDOT is doing is future-proofing. When building a project, UDOT will frequently say, "This project was built to handle predicted traffic levels at 2030, 2035, etc." Waste of money? I wouldn't say so.

[ethanman62187]

In 2008, a Utah house bill allows a portion of this freeway in Utah to be posted at 80 MPH (2nd highest speed limit compared to I10 and I20 in West Texas which is posted at 85 MPH).

[CL]

In 2008, a Utah house bill allows a portion of this freeway in Utah to be posted at 80 MPH (2nd highest speed limit compared to I10 and I20 in West Texas which is posted at 85 MPH).

Yes, we know about the 80 mph limit. There is no 85 mph in the United States.

[ethanman62187]

In 2008, a Utah house bill allows a portion of this freeway in Utah to be posted at 80 MPH (2nd highest speed limit compared to I10 and I20 in West Texas which is posted at 85 MPH).

Yes, we know about the 80 mph limit. There is no 85 mph in the United States.

Well, 85 MPH do exist the United States.

[NE2]

Nope. There's no integer between 84 and 86.

[agentsteel53]

Nope. There's no integer between 84 and 86.

you mean between 80N and 15W.

[NE2]

Nope. There's no integer between 84 and 86.

you mean between 80N and 15W.

No, between (CT) 15 and (NY) 17.

[corco]

Well, 85 MPH do exist the United States.

Nope- the state of Texas has authorized it, but a full review of which roads can get it has to be conducted before TXDOT is allowed to actually implement it- it'll be a couple years.