I-35 / US 30 Flyover Progress
- Thread starter scottie33
- Start date
The project started on 2013.
They hope the current bridge can remain in use through completion.
They hope the current bridge can remain in use through completion.
That's been going on for a long, long time. Those big interchange reconstructions take forever because as a contractor you can't be efficient. Lots of traffic switches, lots of changing operations, and you can never get a production line going.
Please, don't take the Slater route! Last thing I need is for more cars driving 5 under the speed limit and flipping you off when you pass them! Less traffic on my route would be favorable
It's clover leaf.The concept has been around for a long time. They aren't hard to maneuver if you have some common sense. I don't think that it is the best design but if people could learn how to merge into traffic it wouldn't be that big of a deal. Just wait there are still going to be problems with merging in the new design.
That's a bold move making such a thinly veiled threat on a contractor's life in a public forum.
Sorry, but there's a reason they're changing it. That much traffic merging and exiting, combined with limited visibility from those merging (because of the curve) at the same short stretch of road at different speeds (traffic on the ramp is going to be slower) is a recipe for failure. The cloverleaf has inherent issues
Given I work in Missouri, but the City I work for does not always go with the lowest bid. We're able to factor many things in, knowing that the cheapest option is not always the best.
Can a traffic engineer tell us why the exits ramps are so dang huge here? It seems like they could have done the same things in about 1/4 of the space.
It also matters if the projects was sent out as a request for proposal or a request for qualifications. many projects around here are sent out as a request for qualifications and they choose the winner based on qualifications without even discussing the price.
Truth. Not always the best design depending on speed and traffic volume. The old traditional design works in the Twin Cities where congestion has slowed both the merging and exiting traffic. For the higher speed and high volume intersections the merging and exiting has a longer and median separated lane of it's own on the highest volume road. The highest speed/volume one are getting flyovers although some of them can freak you out a little in ice/snow because of icy decks. You don't want to "flyover" literally.
I agree that it's not a perfect design. I just think that with the lack of people who know how to merge properly the new design will still have plenty of issues. You are going to have northbound and southbound merging at the same time people are going to be trying to take the Dayton exit. That seams like a recipe for disaster also.
Yeah, it's a bit different in Iowa. Any DOT project, including city streets that are classified as a DOT highway are lowest responsive bid. Cities around here have followed suited to an extent, but some reserve the right to throw out a bid for several reasons.
AWARD OF CONTRACTS
The Iowa DOT's practice is to award a contract to the lowest responsive bidder within 30 days of the letting or reject all bids on the project. Contracts for state projects are normally sent to the contractor within one week of the letting. Contracts for city and county projects are sent to the appropriate local jurisdiction. The local agency makes the final award decision.
Are you talking about this location?
https://www.google.com/maps/@41.8143622,-93.301095,1625m/data=!3m1!1e3
Seems to me like standard ramps
I remember designing that intersection during highway design class along with everyone else.
Don't think this question has been answered. Who is the contractor on the I-35/US-30 interchange project?
The difference is that in the new design there is a lot more time to make that merge. The issue with the standard cloverleaf design (and why it is no longer used) is because you have traffic trying to merge on and off the interstate in a very short stretch of road. At this intersection today you have about 600 feet of space to merge. If you're going the speed limit, it takes about 6 seconds to drive from one end of the merging area to the other. You're realistically not going to merge in there right at the far end of the merging area, so really you only have 3-4 seconds. If traffic is busy at all, there are going to be 2-3 cars in there at least so now you have to find a gap and get into it all in that short time. Meanwhile you have to judge the speed of the other cars and speed up or slow down as appropriate. The cars coming in are driving in a curved path so it's really hard to judge their speed. And if there's a semi or two in there, forget about it. You have almost no opportunity to do the merge.
In the new design, you have a few thousand feet to merge with people who are going the same direction and same general speed as you. You have way more time and it's a much easier task.
When you do traffic design you are not designing the highway for the optimum driver, or even the top third. You could design the bare minimum space needed to merge and assume perfect meshing for traffic and it would work if only the best professional drivers were allowed on the road. Realistically, you have to design to make things easy because people aren't perfect and you can't expect them to be 100% tuned in 100% of the time.
Assuming it was awarded to the lowest bidder (I don't know that for a fact), Minnowa Construction would be the contractor according to the bids received:
https://www.bidx.com/ia/apparentbids?contid=85-0354-183
Also, the reason I was told that one of the piers was demolished and reconstructed was because there were some serious defects with the concrete (lots of honeycombing & voids) that couldn't be repaired. You can see some of these types of issues in the photo from the Ames Trib below:
http://www.amestrib.com/storyimage/IA/20170920/NEWS/309209984/EP/1/1/EP-309209984.jpg
