Earlier this week, news surfaced that the Kellogg Ave-3rd Street bridge connecting Lowertown and Dayton’s Bluff is structurally deficient. The bridge, built in 1982 by MnDOT, has four vehicle lanes, the outer two largely supported by concrete cantilevers with pier supports built in the middle.
It took only one day before the Infrastructure Opportunists in our state started taking advantage of this situation, and St. Paul officials were happy to play along. Doesn’t this example show the need for more money for roads and bridges? Isn’t this bridge a prime candidate for replacement? Of course, we need to maintain safety for bridge users. But let’s not get tunnel vision when looking at rational responses.
So Far, Irrational Responses
Can’t I Lever?
What happens when a bridge overbuilt for capacity and underbuilt for structure becomes a liability after merely three decades? It becomes a battle cry for the wrong reasons.
City Council president Kathy Lantry says St. Paul is working with “county, state and federal partners to identify funding sources to build a new bridge as soon as possible” according Finance & Commerce.
The City of St. Paul seems set on replacing an already-too-big bridge with an even bigger bridge. “Do we have to repair the piers or not to widen the deck?” asked city engineer John Maczko. He notes that the existing bridge is not suitable for walk/bike/bus. Well of course it’s not, on a bridge where 80% of the deck profile is used for unneeded lane capacity for motor vehicles.
And maybe if MnDOT had invested in a design with a longer lifespan for the city rather than a wider wingspan for cars that never showed up, we would have been able to avoid this jam in the first place.
Yet a rational response must look forward, not backwards.
Four lanes not needed
Concrete Gateway to the East Side
This bridge carries 9,900 vehicles per day (MnDOT, 2013) less than half the traffic of parallel E 7th St four blocks north. By comparison, the 2-lane Smith Ave High Bridge over the Mississippi carries 13,900 vehicles per day – 40% more vehicles with half the lanes. 9,900 vehicles per day falls squarely into the space where two lanes is more than adequate, especially considering that this half mile stretch has no turns or conflict points.
One complicating factor is the Gateway BRT project, designed to connect park & rides in undeveloped Lake Elmo with our urban transit network. The locally preferred alternative would approach Downtown St. Paul by way of Mounds Blvd and this bridge. But this isn’t much of a complication: signal prioritization at the bridge approaches would be likely sufficient to keep buses moving. Dedicated turn lanes at 3rd Street/Mounds Blvd intersection or even a dedicated bidirectional transit lane on the bridge would ensure transit advantage even if there was some shocking increase in vehicular usage of this bridge, despite the overall trend that we’re past peak car use.
Human-scale connectivity to the east side
It’s true, this bridge is hostile to those who walk or bike across it. It has a narrow sidewalk, sandwiched between a curb and a guardrail, and no bicycle facilities. Luckily, there’s a large amount of bridge deck that is not structurally sufficient to support the loads of massive steel cages moving across it, nor is it needed for vehicular capacity even if it was structurally safe.
Our broken funding process is making things worse
CC-A 2.5 / Wikimedia
The strange way we fund infrastructure repair contributes this current irrationality.
If the city spent $8 million to get the bridge to last for another four decades, it would then forfeit the opportunity to get a new bridge (estimated at $40 million) with “outside assistance,” as Public Works spokesman Dave Hunt notes in the Finance & Commerce piece.
So it sounds like St. Paul would rather have someone else build them a larger, fancier bridge that costs at least $32 million more because it would potentially save them from a $8 million expense – at least until the next bridge is due for repair. Don’t listen to the Infrastructure Opportunists: the root of this problem is not a lack of funding, but the inefficient way we plan and fund projects.
A cheap, effective rational response
To recap what we know about the Kellogg bridge:
- Structural issues with cantilevered piers means no vehicular traffic on outside of bridge deck. Emergency striping change will reduce four lanes down to three, causing Mayor Coleman to direct agencies towards “short-term traffic flow alternatives until a new bridge can be built.”
- The traffic isn’t there to begin with – seriously, Mayor Coleman. The bridge had far too much lane capacity. The Smith Ave bridge by comparison carries 40% more vehicles on half the lanes.
- The bridge is hostile to bicyclists and pedestrians, a major factor separating the thriving Lowertown neighborhood from the downtrodden East Side. Stronger links could encourage placemaking on the hill and encourage private investment in the neighborhood which would result in long-term growth of tax base for St. Paul.
- The city and the Infrastructure Opportunists are already salivating at a $40 million+ replacement rather than a $8 million repair.
Considering this, the obvious solution is to repair the existing bridge in a way that accommodates existing traffic, welcomes new walkers and bikers, and prepares the way for future transit service — for about 75% less than a new bridge. Seriously, it’s that simple. Here are a few potential ideas which would enhance the bridge with sidewalks and cycletracks on both sides, while saving a cool $25-30 million.
St. Paul: Take some of the money saved and invest it elsewhere. I hear you have some potholes that need filling.
Not going to argue that the bridge is overbuilt for motorize vehicle traffic- even total VMT, which is what is important for capacity planning, is holding steady rather than going up. But you have to look at the overall cost over the long term. New bridges really are better than what was built in decades past- major new bridges like the Wakota Bridge, St. Croix Crossing, and new Dresbach Bridge usually have a 100 year design life. So you have to look at what is most cost effective long term, which may or may not include patching up the existing bridge.
We have no idea what we’ll need in the long term. Would we need that much capacity? A different type of capacity, with more weight per square foot, for some other type of vehicle? 100 years ago, we were building bridges for wagons in the country and streetcars in the city. The St. Croix Bridge is less than 90 years old. They should have known we’d need more lanes.
Actually the Stillwater Bridge was only about 20 years old when they started looking at building a “High Bridge” and getting the through traffic out of downtown. (If you look at a map you see MN 96 almost lines up with WI 35/64- that’s why). But since it was built before the current round of “value engineering” it’s lasted a 100 years. So I don’t think going back to 50 year design lives is a good decision. Most of the 50 year bridges built starting in the1960s are being torn down because they’re falling apart, not because they can’t handle traffic. In 50 years if we need something more we can build another bridge next to it and still have 50 years of life out of the original structure. I personally don’t believe the rental model of self-driving cars will come to pass, but if it does the weight and size of the vehicles will go down since it will be easy to “order” a pickup truck for the boat and wood chips on the weekends and have a small city car for trips to the office (assuming all the people that used to work in downtown aren’t telecommuting).
We can likely count on a new bridge being built with even more excessive capacity than exists today–see John Maczko’s comment for the proof of that likelihood. Given this, it seems better to spend $8 million now to extend the lifespan of the existing bridge and then go ahead and build the 100 year bridge at the right size after this brig is exhausted. That’s X years + 100 of a right-sized solution rather than 100 years of an over-sized solution.
Well said and very persuasive, especially the comparison between the Kellogg and Smith bridges; I hope someone at City Hall reads this, but given the excitement they showed in print and on the radio about spending public money, I doubt they’ll be convinced.
pace Monte, it’d be nice to know how long we could expect the bridge to last under this road diet plan. 30+ years could save a lot of money.
It’s not fair to say they can use the rest of the money on potholes since the entire excitement is about getting someone else’s money for a sexy project like this.
On the first picture, how many millions are spent on the street trees? Really, I am amazed sometimes how much small things like sharrows or street signage cost.
On the whole I am with either of these plans as long as there is some significant life left to the rest of the bridge after the repairs/updates. If it’s only for another decade probably not.
Also, where are the lookout benches we were promised in the new bridge? Maybe I’m making that part up… can’t remember.
Great piece, Matt. Thanks for writing it.
+1 Awesome piece.
I’d quibble with some of the particulars of Matt’s suggestions (in particular a tree median on a bridge?!), but the basic gist is sound. I’d also question the operational utility of a bi-directional transit lane…I just don’t see that as needed. Given that traffic tends to be higher in the PM, typically outbound, and with the uphill grade on that side, I could see keeping 2 lanes eastbound towards Mound Blvd, but that still does leave the existing bridge with 1 lane more than is needed. Counter point to that one is that the High Bridge operates on similar parameters, with more traffic (as Matt noted), but only has a single southbound lane vice two.
I’m not trying to prescribe a particular use of the space, other than to just point out approximate ideas to use with the extra deck space. Not sure about the bidirectional BRT lane, that was just an idea too. If autos were causing BRT delays, I imagine it would mainly be eastbound up the hill due to the stoplight at Mounds. So maybe it would make sense for that to be a BRT/HOV lane eastbound during peak hours, and an emergency pulloff space the rest of the time. Westbound BRT could have some sort of lane that starts after the bridge, either on Kellogg or maybe wrapping around the stadium if they decide to route it through St. Paul rather than ending it at SPUD. Whatever happens, we have a lot of bridge deck to work with here, assuming we throw away the presumption of at least four general purpose lanes.
Great ideas Matt. Have you done any PV / cost of funds calcs on this? Even if we had to spend $60 million in 20 years we’d likely be ahead spending the $8 today and $60 million then.
Is it a good idea to assume that a $60 million bridge today will still cost $60 million in 20 years?
He’d included an estimate of $40 million today so I very roughly up’d it to $60 million cost in 20 years. Probably could have worded it better. EG, $8 today + $60 in 20 years might be better than $40 today.
Sorry, didn’t catch that
Another article with worrisome comments from…
Kathy Lantry: “By the time we did the $8 million repair, the bridge is a year older. And you still won’t get people down to the Vento Nature Sanctuary, it still wouldn’t have bike lanes or be better lit or ********carry more cars******** or accommodate [bus rapid transit].”
and the Strib notes Maczko lists one of several options as “putting a wider deck on the existing piers”
http://www.startribune.com/local/stpaul/277166601.html
Is someone hiding AADT data from our engineers and electeds?
I’m sure our engineers are well aware of the AADT, and this is at least a borderline case. The engineers want a new bridge that’s going to last a 100 years and not continue to be a maintenance headache. But our elected aren’t engineers so acting rational in regards to highway policy doesn’t happen… We’re converting MN 60, AADT in the 5,000s, to a four lane expressway because of a pork barrel provision in the gasoline tax bill that our elected officials inserted.
Good article. Another problem with a new bridge is Lowertown has more than its share recently of big, construction projects generating noise, dust. road closures, cement trucks and water shut-offs. The Lafayette Bridge, the ballpark, the Green Line.
Lowertown could use a break.