AARoads Forum

Please login or register.

Login with username, password and session length
Advanced search  


New rules to ensure post quality. See this thread for details.

Author Topic: UDOT wants to make US 89 a freeway from I-15 to I-84  (Read 14157 times)


  • *
  • Offline Offline

  • Posts: 8495
  • Location: Bay Area, CA
  • Last Login: September 12, 2021, 12:44:33 AM
Re: UDOT wants to make US 89 a freeway from I-15 to I-84
« Reply #50 on: May 18, 2021, 04:13:26 PM »

Finally tracked down the agenda item for the $60m addition from last month's transportation commission meeting: https://utahdot.granicus.com/MetaViewer.php?view_id=2&event_id=243&meta_id=30305 (rather large PDF - pages 1-2)

The original scope for the US-89 project stopped short of the I-84 interchange due to funding constraints. The public has been very vocal about concerns of current and future traffic backup at the interchange at I-84. In response to the concerns, UDOT has done additional traffic analysis and has confirmed that the traffic can back up for more than a mile on Northbound US-89 during the PM peak and add
more than 5 minutes of delay to commuters. This delay is only anticipated to increase with the completion of the US-89 reconstruct project.

The additional scope proposes to add a new SPUI (Single Point Urban Interchange) at the I-84 / US-89 junction. New on and off ramps will be built to provide better sight distance, standard deceleration and acceleration lengths and improved storage. The bridge on I-84 over the Weber River will also be reconstructed as part of this project.

So it appears they are indeed converting the existing partial cloverleaf to a SPUI. Personally not a fan of that, but the geometry on some of those existing ramps does suck (particularly the ramp onto westbound 84) and definitely could use some improvement.

Unless there was a concurrent project to increase capacity on I-84, especially west toward I-15 and Ogden, configuring the northern terminus of the US 89 project with a SPUI instead of a free-flow interchange would make sense to regulate the flow of NB traffic onto WB 84.  Otherwise the segment of 84 west of the interchange would likely become a chokepoint, particularly during commute hours.  Not so much with the opposite traffic movement unless the RH turn onto US 89 was itself signal-regulated. 


Opinions expressed here on belong solely to the poster and do not represent or reflect the opinions or beliefs of AARoads, its creators and/or associates.