Iowa Notes

[Revive 755]

US 30 in Boone seems to be getting a roundabout at Corporal Rodger Snedden Drive as part of a RISE grant to Boone - see the bottom of https://www.news.iowadot.gov/newsandinfo/2024/10/actions-taken-at-the-iowa-transportation-commission-meeting-on-tuesday-oct-8.html.

So two roundabouts for US 30 in Boone if there is still one planned to replace the all-way stop at Story Street?

[JREwing78]

I realize these can't be the busiest intersections on a divided highway in Iowa, but what's the point of having a southerly expressway (near-freeway) bypass of Boone if they're going to make through traffic on US-30 navigate these roundabouts?

The obvious and correct answer would be to build out interchanges at these spots. Is Iowa's DOT that broke that it's unable to install an interchange in these locations? They went to considerable trouble and expense to build out a high-speed 4-lane US-30 bypass of Boone, and now we're kneecapping it by making US-30 traffic slow down unnecessarily.

I'm normally a roundabout advocate, but not as an intersection on a high-speed divided highway where folks tend not to expect them. I'm picturing a lot of instances where through traffic on US-30 is surprised by the sudden appearance of a roundabout, and ends up blowing right through it at highway speed.

Building a roundabout may be far cheaper than an interchange, but they've effectively stuck with it for at least the next 20 years until, finally, someone comes to their senses and fixes it properly with an interchange.

[PastTense]

Anyone know when the construction on US 63 south of Tama will be done? It was scheduled to be done in October and then they delayed it to November 15 according to 511ia.org. Is that accurate?

[pianocello]

I realize these can't be the busiest intersections on a divided highway in Iowa, but what's the point of having a southerly expressway (near-freeway) bypass of Boone if they're going to make through traffic on US-30 navigate these roundabouts?

The obvious and correct answer would be to build out interchanges at these spots. Is Iowa's DOT that broke that it's unable to install an interchange in these locations? They went to considerable trouble and expense to build out a high-speed 4-lane US-30 bypass of Boone, and now we're kneecapping it by making US-30 traffic slow down unnecessarily.

I'm normally a roundabout advocate, but not as an intersection on a high-speed divided highway where folks tend not to expect them. I'm picturing a lot of instances where through traffic on US-30 is surprised by the sudden appearance of a roundabout, and ends up blowing right through it at highway speed.

Building a roundabout may be far cheaper than an interchange, but they've effectively stuck with it for at least the next 20 years until, finally, someone comes to their senses and fixes it properly with an interchange.

Eh, I'm sure the DOT considered an interchange but decided it wasn't worth the expense (which I tend to agree in this case). The AADT is in the 10K range, and it drops off pretty dramatically west of Boone - so it doesn't seem like there's much through traffic to speak of. After all, Boone is the biggest town US 30 passes through west of Ames, and the 4-lane stretch only continues as far west as the next town. Given that, seems like Iowa DOT just had to make the choice between a roundabout and a signal.

Speaking of slowing down unnecessarily, the 4-way stop at Story St that someone mentioned upthread seems to have been there since the 60s or 70s, when the bypass was originally built. So it's not like it's a new 4 lane road, or like anything is being kneecapped.

[Revive 755]

Eh, I'm sure the DOT considered an interchange but decided it wasn't worth the expense (which I tend to agree in this case). The AADT is in the 10K range, and it drops off pretty dramatically west of Boone - so it doesn't seem like there's much through traffic to speak of. After all, Boone is the biggest town US 30 passes through west of Ames, and the 4-lane stretch only continues as far west as the next town. Given that, seems like Iowa DOT just had to make the choice between a roundabout and a signal.

These days there should also be an RCUT/superstreet option.

What are the chances Boone becomes a bit of a commuter suburb for Ames?

[iowahighways]

What are the chances Boone becomes a bit of a commuter suburb for Ames?

Boone County is already part of the Ames MSA, along with Story County.

[DandyDan]

Eh, I'm sure the DOT considered an interchange but decided it wasn't worth the expense (which I tend to agree in this case). The AADT is in the 10K range, and it drops off pretty dramatically west of Boone - so it doesn't seem like there's much through traffic to speak of. After all, Boone is the biggest town US 30 passes through west of Ames, and the 4-lane stretch only continues as far west as the next town. Given that, seems like Iowa DOT just had to make the choice between a roundabout and a signal.

These days there should also be an RCUT/superstreet option.

What are the chances Boone becomes a bit of a commuter suburb for Ames?

One of the people I work with used to live in Ames and when he lived there, he worked with many people from Boone. It's there already.

[WhitePoleRD]

30 west of Ames is so weird.

Two big curves to conform to section boundaries, an exit for 17 east of town that locals never use, and a four way stop for the entrance into town that is used. Then west of there, an exit for 169 and then the freeway just...ending.

[SEWIGuy]

30 west of Ames is so weird.

Two big curves to conform to section boundaries, an exit for 17 east of town that locals never use, and a four way stop for the entrance into town that is used. Then west of there, an exit for 169 and then the freeway just...ending.

There is no need to have a freeway west of there.

[The Ghostbuster]

There probably isn't enough traffic to warrant US 30 being expanded to four lanes west of there either. The Lisbon-to-DeWitt segment probably also doesn't need to be expanded to four lanes, does it?

[WhitePoleRD]

30 west of Ames is so weird.

Two big curves to conform to section boundaries, an exit for 17 east of town that locals never use, and a four way stop for the entrance into town that is used. Then west of there, an exit for 169 and then the freeway just...ending.

There is no need to have a freeway west of there.

Oh no argument from me. Honestly I think the 4 lane could have happened as a Y intersection with Lincoln Way on the edge of town and continued as two lane to Boone. Or, since Boone really is the major traffic dropoff that it ended at the 4 way intersection.

[iowahighways]

The left exit to "stay" on I-35 in Des Moines is no more, as the new flyover ramp at the East Mixmaster interchange with I-80 and I-235 opened today:

https://who13.com/news/metro-news/new-flyover-bridge-at-east-mixmaster-now-open/#

[rte66man]

The left exit to "stay" on I-35 in Des Moines is no more, as the new flyover ramp at the East Mixmaster interchange with I-80 and I-235 opened today:

https://who13.com/news/metro-news/new-flyover-bridge-at-east-mixmaster-now-open/#

We were through there on the 20th and could see it looked ready to go. Disappointed we didn't get to drive it.

[midwesternroadguy]

There probably isn't enough traffic to warrant US 30 being expanded to four tween lanes west of there either. The Lisbon-to-DeWitt segment probably also doesn't need to be expanded to four lanes, does it?

When I drove the segment between DeWitt and Lisbon 30 years ago, I was surprised at how busy it was, and how few passing opps there were.  I suspect it was due to the relatively high number of towns along that stretch.  It could have used some passing lanes at a minimum.  IaDOT does climbing lanes, but not extended passing lanes like MnDOT or WisDOT?

[DandyDan]

There probably isn't enough traffic to warrant US 30 being expanded to four tween lanes west of there either. The Lisbon-to-DeWitt segment probably also doesn't need to be expanded to four lanes, does it?

When I drove the segment between DeWitt and Lisbon 30 years ago, I was surprised at how busy it was, and how few passing opps there were.  I suspect it was due to the relatively high number of towns along that stretch.  It could have used some passing lanes at a minimum.  IaDOT does climbing lanes, but not extended passing lanes like MnDOT or WisDOT?

I am unsure of the rest of the state, but US 18 has two sets of extended passing lanes. One set, for each direction, is between Ventura and Garner and the other is between Britt and the IA 17 intersection.

[The Ghostbuster]

Was the US 18 freeway ever proposed to continue west of Interstate 35? There are stubs at the interchange, and it looks like something could have been built, if not for the wildlife areas west of the US 18/Interstate 35 interchange.

[DandyDan]

Was the US 18 freeway ever proposed to continue west of Interstate 35? There are stubs at the interchange, and it looks like something could have been built, if not for the wildlife areas west of the US 18/Interstate 35 interchange.

I don't know if a serious proposal was ever made, but I can say there isn't much need for an extended freeway west of I-35. Such a road would go to Garner and they need a more modern US 18 than a freeway that takes you there.

[Molandfreak]

There probably isn't enough traffic to warrant US 30 being expanded to four tween lanes west of there either. The Lisbon-to-DeWitt segment probably also doesn't need to be expanded to four lanes, does it?

When I drove the segment between DeWitt and Lisbon 30 years ago, I was surprised at how busy it was, and how few passing opps there were.  I suspect it was due to the relatively high number of towns along that stretch.  It could have used some passing lanes at a minimum.  IaDOT does climbing lanes, but not extended passing lanes like MnDOT or WisDOT?

MnDOT is extremely stingy regarding passing lanes, especially compared to MDOT or WisDOT. There's an adequate amount of them on US 2 and M-28 along the South Shore, but when you get past the expressway on TH 61, there's only two passing lanes until the border. Then suddenly, Ontario has them every 5 km or so.

[PastTense]

Was the US 18 freeway ever proposed to continue west of Interstate 35? There are stubs at the interchange, and it looks like something could have been built, if not for the wildlife areas west of the US 18/Interstate 35 interchange.

Yes, it was part of the Iowa's 1968 Highway Plan which proposed a very extensive set of freeways and expressways across the state including a Highway 18 expressway.

US 18 expressway

The idea: A second-tier project, split into 18W (Spencer to I-35) and 18E (the east Freeway 518 junction to the Wisconsin state line).

What happened: Pretty much nothing. A straightening between New Hampton and Postville never got past the drawing board. The Freeway 518 portion was built as part of the Avenue of the Saints.

Forty years later: The interchange with I-35 that opened in 1999 makes it easy to pretend that the four-lane could one day extend along the south side of Clear Lake (the lake) to Ventura, but that's about it. There is a four-lane New Hampton bypass with US 63, though.


https://iowahighwayends.net/maps/1968plan.html

[Great Lakes Roads]

https://evrimagaci.org/tpg/iowa-senate-advances-legislation-on-handheld-device-ban-and-speed-limit-increase-269762

Iowa might be upping the speed limit on certain undivided paved highways from 55 mph to 60 mph... reminds me of what Minnesota did years ago.

[I-55]

https://evrimagaci.org/tpg/iowa-senate-advances-legislation-on-handheld-device-ban-and-speed-limit-increase-269762

Iowa might be upping the speed limit on certain undivided paved highways from 55 mph to 60 mph... reminds me of what Minnesota did years ago.

So the difference between some two lane state routes and the US 20 freeway will be 5 mph. I don't know of any states that allow 60+ on two lane roads that also don't allow 70 on non-interstate freeways

[Mav94]

https://evrimagaci.org/tpg/iowa-senate-advances-legislation-on-handheld-device-ban-and-speed-limit-increase-269762

Iowa might be upping the speed limit on certain undivided paved highways from 55 mph to 60 mph... reminds me of what Minnesota did years ago.

So the difference between some two lane state routes and the US 20 freeway will be 5 mph. I don't know of any states that allow 60+ on two lane roads that also don't allow 70 on non-interstate freeways

Point taken, but all of Iowa's non-interstate freeways have many transitions between freeway and expressway, and I believe even the freeway segments allow farm machinery. I can't see Iowa raising the limit to 70 on those roads. The combines and gravity wagons would be sitting ducks.

[pianocello]

Point taken, but all of Iowa's non-interstate freeways have many transitions between freeway and expressway, and I believe even the freeway segments allow farm machinery. I can't see Iowa raising the limit to 70 on those roads. The combines and gravity wagons would be sitting ducks.

Iowa does a pretty good job of blurring the lines between expressway and non-Interstate freeway. Which I appreciate; speed limits notwithstanding, I think that once signals and high-traffic intersections are removed in favor of interchanges and overpasses, there are better uses of funds than full freeway conversion.

That said, I know at least US 61 between Davenport and DeWitt does not allow farm machinery (Street View Link). I assume other longer full-freeway segments such as US 20 from Fort Dodge to Waterloo and US 218 south of Iowa City have similar restrictions, but I don't know what the length threshold is or what other roads would qualify.

[Revive 755]

I assume other longer full-freeway segments such as US 20 from Fort Dodge to Waterloo and US 218 south of Iowa City have similar restrictions, but I don't know what the length threshold is or what other roads would qualify.

US 218/IA 27 does have a minimum speed requirement between I-80 and IA 22.

[Molandfreak]

https://evrimagaci.org/tpg/iowa-senate-advances-legislation-on-handheld-device-ban-and-speed-limit-increase-269762

Iowa might be upping the speed limit on certain undivided paved highways from 55 mph to 60 mph... reminds me of what Minnesota did years ago.

So the difference between some two lane state routes and the US 20 freeway will be 5 mph. I don't know of any states that allow 60+ on two lane roads that also don't allow 70 on non-interstate freeways

Minnesota doesn't have any non-interstates posted at 70.