Everything you want to know about potholes, but were too afraid to ask! How do they form? What can we do about them? We sit down with engineers Doug Fischer and Bev Farraher to chat about all that and more!
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- Anatomy of a pothole video
- Doug’s website: The Highway Doctor
- Spreadsheet comparing vehicle weights and damage to the street
- Neighborhood electric vehicle
- Article about vehicle weight damage
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Our theme song is Tanz den Dobberstein, and our interstitial song is Puck’s Blues. Both tracks used by permission of their creator, Erik Brandt. Find out more about his band The Urban Hillbilly Quartet on their website.
This episode was edited by Jeremy Winter, and was transcribed and hosted by Ian R Buck. Guest acquisition was handled by Sherry Johnson, with production assistance from Christina Neel. We’re always looking to feature new voices on the show, so if you have ideas for future episodes, drop us a line at firstname.lastname@example.org.
Ian: [00:00:00] The wildest pothole story that you can think of.
Bev: [00:00:03] Found fish in potholes.
Ian: [00:00:05] Oh my God.
Bev: [00:00:07] That’s rare. It’s post flooding. So to be fair, it wasn’t the potholes as much as the flooding.
Ian: [00:00:15] Welcome to the Streets.mn Podcast, the show where we highlight how transportation and land use can make our communities better places. Coming to you from beautiful Seward, Minneapolis, Minnesota. I’m your host, Ian R Buck. There are many points of division in our society, but one thing that brings all Minnesotans together is how much we like to complain about potholes. This last winter was especially bad in the Twin Cities. It got us wondering if there’s anything that can be done about the situation, or if we have to resign ourselves to teeth rattling streets every spring. To answer these and many other questions about potholes, we turn to a couple of experts. Doug Fischer, who is program director for government markets at TKDA and previously worked at Anoka County as an engineer. He is sometimes referred to as The Highway Doctor. And Bev Farraher, city engineer who works as operations manager in the Saint Paul Public Works Department. Doug and Bev, welcome to the show.
Bev: [00:01:16] Thanks.
Doug: [00:01:17] Thanks for having me.
Ian: [00:01:18] I kind of want to start by just asking, like, what’s a street? Right? Because potholes, they form in streets. And what is the make up of a street like when I’m looking at it from above, I can tell that, like, okay, a street’s made of asphalt and like a sidewalk is made of concrete. But beyond that, I’m like, I have no idea what’s underneath all that.
Bev: [00:01:35] Well, a street is a public roadway in the public right of way, and it can be constructed in a variety of ways, but in an ideal world, it has an engineered profile, which means it’s got a cross section and an alignment down the center of the road that allows it to drain appropriately, so it can function well in all kinds of weather. And ideally also it has a subbase and a base, and then a driving surface that can either be asphalt or concrete. Most city streets would be asphalt because it’s a more conducive pavement for the kind of utility cuts that happen in urban or even more rural situations with roadways. But you can see concrete streets that are not interstates, for example.
Ian: [00:02:24] So when you say utility cuts, that means like we need to send a crew to work on whatever piece of public utility that’s underneath the street? And it’s easier to do that with asphalt?
Bev: [00:02:34] Yes. Okay. If you think of it like Play-Doh, asphalt is basically industrial level public works, Play-Doh that utility companies, communication companies. And by that I mean your Excel, your Xfinity. All those folks can cut through the pavement to get to their utilities or to install new utilities if they’re not direct boring, which is another way to install things, but is less common in some areas because of the amount of utilities that are underneath the roadway. You would be astounded, for example, at the number and type and size and age of utilities in downtown Saint Paul underground. Very, very amazing amounts.
Ian: [00:03:17] Is that kind of why everybody’s conception of going downtown is,”okay, well, I’m going to have to figure out what detours to take around all of the construction that’s always going on downtown.” That’s not all street reconstructions, right? That’s a lot of that is utilities then?
Bev: [00:03:31] Correct. Before we do street reconstructions, we have discussions a year or more ahead with communications, utilities and all sorts of folks to talk about what do they need to do to their infrastructure to move it, to get it out of the way of the planned new construction? Or as in, in the case with Saint Paul Regional Water Services, they’re very good about coming in and replacing old water line before we come in with street reconstruction so that they’re not working in the same space that the contractor doing the reconstruction is doing. And they also have made sure that they don’t have to affect the roadway downtown. We actually put a five year moratorium on roadways that are reconstructed downtown for optional work underneath the roadway. But if there’s an emergency utility issue, we have to let them cut into the roadway.
Ian: [00:04:20] What is the what’s the reasoning behind the five year moratorium?
Bev: [00:04:23] When we, as folks who are using taxpayer money, use that money to reconstruct the roadway and as the adjacent property owners who are assessed for that work, in most instances, when everyone has invested that kind of time and money and disruption to their lives, the last thing we want to do is have someone come in and make a cut in that roadway, even if they restored extremely well, really good quality. That is now a call it a flaw, if you will, in the roadway that allows the potential intrusion of water, which is what makes roadway degradation happen and causes potholes.
Ian: [00:05:03] It’s like any time that you have surgery, right. That’s going to leave some effect on the body. Yeah. Yes. So you mentioned like two layers underneath the asphalt. What were those? What are those made of?
Bev: [00:05:15] Sub base and base are made out of aggregate.
Ian: [00:05:18] Okay. So that’s that’s kind of looser rock and gravel and stuff okay. Cool.
Doug: [00:05:23] You know some you know streets have just seen full history of what they were. It’s almost you know, some streets started as a sand road and then it was a oil stabilized road. And then maybe it was a gravel road then then they put some pavement on it, you know. So. And the, the urban core. Yeah. You’ll see some, some brick pavers, you’ll see a lot of old concrete. The old trolley car line rails may still be in there, which makes reconstructing those streets very, very complicated of course. But it always is nice now to, you know, when you’re rebuilding a road instead of just adding on to what’s there to, let’s remove it and engineer it and build it right.
Ian: [00:06:08] Right, right.
Bev: [00:06:09] And get the curb and gutter in. That allows the decent drainage, huge.
Ian: [00:06:14] Which is, you know, and that’s the kind of reconstruction that comes around, you know, every like 60 to 120 years, depending on how much funding we’re putting into into that.
Bev: [00:06:24] You’re probably closer to correct in what the actual timeline is, but we’d prefer it to be around 50.
Ian: [00:06:32] Directly shifting our attention to potholes, what is a pothole? How do we define a pothole?
Doug: [00:06:37] Well, a pothole is an imperfection in the pavement caused by water and traffic. So it’s it’s a blemish in the pavement, a void in the pavement. And it is a scar in the road. It’s where pavement used to be and isn’t anymore.
Ian: [00:06:57] There’s cracks that are small enough that one would not call that a pothole. But like that is where potholes come from, right? That’s that’s the start of one, right?
Doug: [00:07:05] That’s the door that opens the water to get into the sub base, the base and the sub base. And then when you combine that with the freezing action that we get in the wintertime and in the spring time with the freezing and the thawing, that that’s what starts the pothole. And again, you know, the traditional pothole is what everybody thinks is a tire buster, you know, big hole in the pavement.
Ian: [00:07:30] The technical difference between a pothole and a sinkhole is just like a pothole forms from a crack in the top and a sinkhole forms from stuff washing out from below. Okay.
Doug: [00:07:42] Essentially, yeah.
Ian: [00:07:44] So from a technical perspective, like when you guys are sending out crews to do patching and stuff like that, is is there a difference between those small little cracks and like what, what people colloquially think of as a pothole? Or is it just like, oh, the amount of fill that we have to put in there is just like the volume.
Bev: [00:08:03] It all depends on what level of pothole patching you’re pursuing. Okay, so this spring we certainly had as many crews going out as we had bodies that we could get, and they were focusing on the larger holes because we had some thunderstorms this past winter in addition to a ton of snow. But what really got us were the thunderstorms, because when that water comes down in the form of water and it gets into those fissures in the pavement, that scientific action of water as it gets close to freezing, because it was always getting cold. Right after those thunderstorms, water expands. And that’s what creates the tremendous pothole when it comes the spring thaw. And there’s this expansion. The water thaws and it leaves and it creates that that space for the force of the vehicles going over to open it up. So we had massive, massive potholes all over the place. So when we were going out in the spring, we were not focusing on the more narrow crack type potholes because we had to just make sure that people could get from point A to point B safely. As we have moved through this summer, we have shifted our approach to being very aggressive in route patching and complaint patching and the level of patching that we’re doing is addressing everything that we can possibly touch. So we’re going through huge amounts of tonnage to try and get as many of those crack type situations as we can, with the hopes and the plan that by the time winter starts, we’ll have potholes patched all over the place that are sealed up enough that we can make it through this coming winter.
Doug: [00:09:39] And crack maintenance is different than pothole patching. Yeah, pothole patching will happen year round. If there’s potholes that need to be patched, you’ll do that. But the crack maintenance actually is more of a summertime activity. And you’ll see we want to seal up those cracks. And so that when you’re driving down a street and it looks like somebody’s toilet papered the street.
Ian: [00:10:00] Yeah, yeah yeah, yeah!
Doug: [00:10:02] They did, they did. Generally what they’ll do is they’ll be a crack. But then we’ll route it out with a router, maybe a one by one. We’ll go over that crack. Then we. Fill it with elastic material. That material, when it’s when it’s fresh and new, it’s very sticky.
Ian: [00:10:20] Yeah, it looks like tar.
Doug: [00:10:21] Yeah. And so then we cover it with toilet paper. So when people are driving over it, when it’s brand new, it doesn’t stick to their tires. Splash on their fenders or pull it out of the pull it out of the crack that we just sealed. So so that’s that’s a whole different maintenance operation. Is that crack sealing operation.
Bev: [00:10:43] If you’re ever in a situation where you have a bunch of geeky civil engineer public works types in a room, ask them if they should route out the crack before they fill it or not. They’ll get excited because there’s different opinions on it. Controversial topic whether you route it out or not.
Doug: [00:11:01] Well, it’s it’s a cost thing too. You have to identify the extent of your issues. And I always said if I had unlimited budget and manpower and labor force and I mean, we could create some excellent roads. But the real art of engineering is balancing the economics of what we’re doing.
Bev: [00:11:25] And the politics.
Doug: [00:11:26] The politics, the economics, you know, with the engineering to get the very best that you can.
Ian: [00:11:32] Right, right. We’ll get into some of the budgeting and everything in a bit, but yeah. Rough estimate. How many potholes do we usually see every year? We can stick to like a constrained geographic location such as the city of Saint Paul.
Bev: [00:11:49] Well, what I can tell you is so far this year, we’ve received 3695 complaints. 3695 complaints for potholes. And what a complaint is, is not a 1 to 1 ratio of one complaint, one pothole, because folks can call in an entire street or a block or something of that nature. So a complaint can be anywhere from 1 to 20 potholes. So when you do that math, the 3695 times 1 to 20, you get a range. So this was an unusual year. Normally we’d probably get somewhere around 1000 complaints. So we’re looking at quadruple that for this year. I think that would track close to the number of claims we’ve also gotten regarding potholes. So very, very unusual year.
Ian: [00:12:41] Is that like a helpful thing for the public Works department? Like me as a citizen, I’m out there riding my bike and I encounter a big old pothole and I’m like, wow, somebody should know about this.
Bev: [00:12:52] Oh please, yes. We very much like folks to let us know what and where. What we also appreciate is their understanding that we have to evaluate how bad it is and where it is, so that we can send out crews to be efficient in how we’re tackling them. I’m not going to send out a crew to tackle one pothole in one place. That’s not an axle breaker because it’s not efficient. With our city resources. We will get to it as fast as we can. But I need to do the largest effort in the best places I can first. But we really like people contacting us and letting us know where things are, but also appreciating that they might be the eighth caller on that particular location.
Ian: [00:13:35] Yeah, that’s the other thing. 1 to 20 per complaint, but also possibly multiple complaints about the same pothole. Yeah.
Bev: [00:13:42] And we cull those out as we establish, because we have great folks who take in all the complaints and then organize them into various routes that we have so that we’re not just flying all over the place like chickens with our heads cut off. We’re strategic about how we tackle doing the pothole patching.
Doug: [00:13:59] Pothole repairs is not always a one and done operation, too. I mean, when you have those rains, like Bev mentioned in the middle of the winter and it seems like roads are exploding, you may, when you’re throwing cold mix into a wet frozen hole. I don’t care what you put in it, it’s not going to last forever. So sometimes these are just emergency fills just to keep the pothole from being a wheel buster. But people will call up and they’ll say, when are you going to fix this pothole? And our response may be, we did 12 times already, you know, but when you got 15,000 vehicles a day on a high speed road, it’s just going to keep pounding whatever we put in there, out again and again and again. Then in the summer, then we can come back and fix it the right way in the more permanent way.
Ian: [00:14:53] The freeze thaw cycle is such a big part of this conversation. Like is Minnesota, are we the pothole capital of the US? Do we have way more potholes than than other states have to deal with?
Doug: [00:15:03] I think just any northern climate state is going to have the same issues. You know, over the course of my career, I’ve lived from Texas to Minnesota and grew up in Ohio. And our temperature extremes that our pavements have to go through here in Minnesota are some of the highest. You know, we have to design an asphalt that doesn’t get soft and rut in the hot summer months, and we also have to have asphalt that won’t be brittle and crack in the cold winter months. And so the asphalts that we have to have the design, our roads that cover those high extremes and the low extremes make makes it very difficult on our roads. And again, we have to use very specialized additives and modifiers to some of our asphalt.
Bev: [00:15:51] You can recognize that our climate here in Minnesota is particularly conducive to growing potholes and creating potholes. And we have seen a trend in the last several years of going towards more freezing rain, which is Pothole City. Anybody, like Doug said, anybody in a in a climate situation like that is going to be experiencing potholes, but if we had amazing amounts of funding to reconstruct older roadways or construct a decently engineered roadways from the oiled roadways that Doug was mentioning, and get decent drainage and limit the number of cracks on the roadways, we wouldn’t have the ability to create those kinds of potholes, because there wouldn’t be as many failures and fissures in the pavements, but it’s not it’s not happening anywhere in the state of Minnesota just because it’s a true funding challenge. Yeah. So weather combined with infrastructure is what creates the pothole challenge.
Ian: [00:16:46] And I imagine that as the climate changes, we are encountering more challenging situations because, you know, you think about your typical Minnesota winter, midcentury 20th century, right? It was it gets cold in late December and we stay frozen all the way until late February, early March. And now we’re seeing a lot more winters that are – So last winter I was working from home, and so my conception of the winter was, wow, that was a very mild winter because the temperature was very warm, but everybody else who had to commute every single day were like, wow, there was so much snow. And that kind of environment definitely seems like it’s got a lot more of the ingredients that you need for pothole creation, right?
Doug: [00:17:32] If a road in the winter time freezes and it stays frozen, that’s the strongest a road will ever be.
Bev: [00:17:40] Correct.
Doug: [00:17:41] But it’s that when it goes above freezing, below freezing, above freezing, below freezing, and then we add in the rain and the snow and all that moisture. That’s the recipe for pothole.
Bev: [00:17:52] And roadways that are a bit more degraded than one would wish.
Ian: [00:18:03] [musical transition] Now notice that we have named two ingredients for this recipe. Right, there is the freeze thaw cycle of water getting into small cracks and then freezing and expanding and then contracting again at the next melt. But that is not going to cause everything to collapse into potholes unless you have some heavy vehicles driving over it. Once the ice has melted and allowing the asphalt that’s above that crack to collapse back into it due to those vehicles, right. So there have been some studies done that calculated how much damage a vehicle will do to the road. And they found that the the amount of damage goes up by a power of four when measured against the weight of the vehicle per axle. So every time that you are doubling the weight per axle of your vehicle, the amount of damage that the vehicle does to the road actually goes up by by 16 times, which is kind of hard to visualize, you know, on your own. So I went and I put in the weights of a bunch of different vehicles into a spreadsheet and calculated out how much damage they would do. So if we assume if we if we if we normalize to just a regular old sedan like a Toyota Corolla, right. Let’s say a Toyota Corolla, about 3,000 pounds per axle, that’s 1500. And let’s just say that that Corolla has taken a trip that does $1 of damage to the road. Let’s take a look at how much damage we would have done if we had used a bunch of other types of vehicles.
Ian: [00:19:59] So obviously a bicycle is going to come out very, very favorably. Bicycles are like what, 20 pounds? You know, 10 pounds per axle. That is so low that my spreadsheet actually won’t even it shows it as $0.00. It’s it’s ten to the -35th power for that one. E-bikes similar situation. They are a bit heavier but still it’s ten to the -29th power. Uh, but of course sedans are not the most popular cars on the road anymore, right? Several varieties of pickup trucks are, like, consistently the best selling cars in America. The Ford F-150 comes in at 4,300 pounds. So we calculate that out. It’s going to be $4.22 of damage to the road. If we start transitioning to electric vehicles, right? The F-150 Lightning Edition is quite a bit heavier. And so that does $22 of damage to the road. So things are not looking super positive here, given that we’re, you know, trending in a heavier direction. But what happens if we manage to convince people to to scale down their vehicles, right? What about like the smart car, the little two seater that comes down to that’ll bring the damage to the road down to $0.22 for that trip. If we go all the way down to one of my favorite classifications of vehicle, the neighborhood electric vehicle, the Polaris Ranger EV would do $0.10 of damage to the road. And this is all assuming so far that we have like one rider in the vehicle.
Ian: [00:21:54] Because let’s be honest, like most of the time that you are driving your car around, it’s just you. Sometimes, yeah, you’re giving people rides, kids, carpooling, whatever. But like most of the time that that most cars are driving around, they just have the driver in them. But let’s say that you get like a nice big old, like 12 passenger van and you fill it up with like eight people or so. That is a heavier vehicle. It does $90 of damage to the road, but if you divide that by eight people it’s $11.30. So still not great, honestly. Let’s bump that up to like, you know, if we fill it with the maximum number 12 people, okay, $7.50. Definitely better than the F-150 Lightning, but still, that’s the highest price that we’ve seen so far. What about okay, let’s scale this all the way up. What about buses? Right. Public transit. I love public transit. It’s the most space efficient, and fuel efficient way to move people around when using motor vehicles. But a 40 foot bus is very, very heavy 28,000 pounds. Divide that over two axles. Still 1400. Right. And that’s going to do $7,588 of damage to the road. And even if you, you know, pack that bus with the maximum like it’s got 40 seats and it’s got room for 40 people standing if you pack it in to a super unpleasant 80 people on the bus, that’s still going to be $94.85 of damage to the road per person.
Ian: [00:23:30] 60 foot buses actually come out favorably compared to 40 foot buses, because even though they’re heavier, they have three axles, so they have the same weight per axle. And you can divide that over more people, right? So 120 people packed into a 60 foot bus, that’s going to be $63.24 of damage to the road. Looking at coach buses, right, for intercity travel, kind of a similar, similar story, 35,000 pound vehicle with 56 seats in it. So if we pack in all 56 seats, that’s going to be $65 of wear and tear per person. So the takeaway for me is that we definitely we want to be emphasizing as small of vehicles as we possibly can for for most trips. Now, obviously that is not going to be as feasible for like long distance trips. And, you know, we’re not just thinking about like moving people here. We’re also talking about like moving freight, moving goods. Um, so so my takeaway is whenever we have to pack everything in, you know, get those economies of scale. Really what we should be focusing is, is on rail, right? We should be moving as many people by train, moving as much freight by train as we can, and avoiding using like large trucks. Once those items, once those people get into a city area, right, then we want to focus on giving them options to take the smallest vehicles that they possibly can. Bicycles for people and, you know, like cargo bikes or small delivery vehicles for making those last mile deliveries and even, you know, for public transit, right. Like it would be best to focus as much of our effort on like light rail as we can, if we want to optimize for making sure that we’re not spending tons and tons and tons of money on maintaining our roads. I don’t have numbers, honestly, for like comparing the amount of money that it takes to maintain a road versus the amount of money that it takes to maintain a rail line. But I strongly suspect that it is cheaper to maintain a rail line. Um, because they’re, you know, I mean, they’re made of metal and they’ve got ties. They’ve got all this, you know, ballast and everything to, like, hold them in place and you don’t see them getting potholes the way that we have potholes on our streets.
Ian: [00:26:19] [musical transition] Let’s talk a little bit about streets versus highways. You know, we were talking about different capacities and different speeds and designing them differently. I feel like I mean, it’s been a long time since I’ve actually driven on a highway, but being on like a bus on the highway, I feel like I have noticed a lot fewer potholes there than I would on a city street in the Twin Cities. Why would that be? Because it seems like higher speed traffic that’s, you know, a lot of freight traffic like that would be doing more damage to it.
Doug: [00:26:51] Well, I think part of it is you have to maintain a high speed, high volume highway at a much higher level of service than you would a low speed, low volume, because if you got 60,000 vehicles a day at 60 miles an hour on a road, you cannot tolerate potholes on that on that highway. But if you got an alleyway that sees 50 cars a day and they’re driving five miles an hour, they can tolerate the potholes that way.
Ian: [00:27:24] When you say “Tolerate,” you’re talking like that is a safety concern.
Doug: [00:27:26] Exactly, exactly. It’s you’re not going to cause crashes. You’re not going to break vehicles. The level, the function of the street or road or highway that you’re you’re dealing with really will dictate how far you’ll let it degrade before you reconstruct it or resurface it. When you do have potholes on those roads, you’re going to spend majority of your time on on those wheel buster routes.
Bev: [00:27:52] They also have more concrete roadways, especially interstates at the Department of Transportation level. And you do get potholes in those, but it’s more of a function of cracking in the concrete, and it doesn’t develop as fast as it would on a asphalt roadway.
Ian: [00:28:10] Most of the time I can think of is the space between the concrete slabs, and then on that leading edge that gets hit most often by the cars.
Bev: [00:28:19] Yes, that is a fantastic spot for creating problems. And I do know that MnDOT was out a lot this spring and this summer addressing numerous numerous potholes. They had similar challenges to us, but it wasn’t as extreme because their roadways also have rather excellent drainage. And therefore, when we had the thunderstorms that we had this past winter, they were getting decent drainage off of those. We just weren’t always it was a challenge.
Doug: [00:28:49] The freeway system doesn’t have the utilities under the highways like the city streets will, you know, and that that’s huge.
Bev: [00:28:57] They just don’t let people cross. It’s a fundamental thing.
Doug: [00:29:02] So, you know, but on a city street where you not only have your municipal utilities, your water mains, your sanitary sewers, your storm sewers, then you’ve got the gas and you got the electric and you got the telephone and you got another telephone, you got another, you know how many communications companies are really filling up our highways? And then when they’re getting in those roads and they’re making fixes and they’re making patches and they are really kind of different creatures altogether.
Ian: [00:29:33] This probably also comes down to politics and budgets, right? MnDOT gets a lot, a lot, a lot of money to maintain the highways that they have. Municipalities like Saint Paul, they get their state aid roads. Right. Those are partially covered by the state in terms of funding. We have county roads, of course, but then like there’s a lot of street miles that the city is responsible for on their own. Do we want to talk about what are the sources of funding for patching those? And, you know, reconstructing and et cetera, et cetera.
Bev: [00:30:07] Most of our county, our state aid funding for roadways that are state aid roadways goes towards reconstruction. Some small amount does go towards maintenance functionality. And in Saint Paul we’re going to be increasing that amount in 2024.
Ian: [00:30:24] Is that because the state voted to increase that amount or is it…?
Bev: [00:30:28] We got our allocation and we internally determined how much of that allocation is going to maintenance and construction? Okay. We’re increasing the maintenance slightly. It’s about an under discussion right now. It’s about $7 million more going towards maintenance as opposed to construction. So it’s a diminishment of construction. But Saint Paul’s done very well pursuing grants of various types for construction and federal funding. Still a huge, huge construction program going on. But we do get funded for much of our maintenance through the general fund for roadways. Okay. And so that’s property taxes is what that comes down to.
Ian: [00:31:05] And a little bit from the gas tax, I imagine.
Doug: [00:31:09] Right. A lot of the transportation funding is comes through the Minnesota Highway Users Tax Distribution Fund, which is. Three legged funding stool. So gas tax is part of the funding tab fees. When you renew your your plates and get new tabs on your license plates, that goes into that pool. The third leg is.
Bev: [00:31:35] Sales tax on vehicles.
Doug: [00:31:37] Yep. The motor vehicle sales tax. It’s been added and modified over the years, but that’s essentially what it does. And again the state, MnDOT, gets the lion’s share of that. Counties get a big share of that. And then the cities over 5000 get a share of that. So that’s that’s our primary source of funds. But it doesn’t cover everything. And then there’s certain roads that don’t get those funds. You mentioned the state aid routes. And on the county side they’re called county state aid highways. On the city side, they’re municipal state aid streets. Those are eligible to use those funds, but the whole system isn’t comprised of state aid streets and highways. So that’s where the property tax has to come in and fill that void.
Bev: [00:32:25] And the state aid funding doesn’t cover fully the maintenance it tries. It’s not that they’re falling down on it. It just doesn’t fully cover it. And I misspoke before when I said $7 million. It’s actually $700,000.
Ian: [00:32:36] Oh it’s a big difference.
Bev: [00:32:38] Yeah it is a big difference. I was thinking of some other thing we’re trying to accomplish. And it is meaningful because it will go directly into people and materials that we’ll be using in maintenance.
Ian: [00:32:49] That other thing that you were, uh, thinking of wouldn’t be the 1% sales tax?
Bev: [00:32:55] Yeah, the local area sales tax that we’re discussing and will be a voter referendum.
Ian: [00:33:01] [music plays under] In from the future here. The referendum did indeed pass. So $7 million will be generated from sales taxes in Saint Paul to pay for road reconstructions and some park stuff, and that that money would have been coming from property taxes otherwise. So now that burden will be shifted onto people who come to Saint Paul for shopping or for events or whatever, in addition to the residents who live and work and shop in Saint Paul. [music ends]
Doug: [00:33:35] Yeah, there’s other funding sources. Some communities, some counties implement a wheelage tax, some communities have those local option sales tax that they they will do as well. So going to the property owners on property tax you know political debate is that is that appropriate?
Ian: [00:33:56] Right, right. Is that. Yeah. Like me as, as a resident who pays property tax. But I only own bicycles and I do very, very little damage to the road when I’m traveling around is yeah like it.
Doug: [00:34:09] Right.
Bev: [00:34:10] But you you achieve all the benefits of a functioning roadway system of the fire department being able to access you, that police department, the Prime delivery folks, the grocery delivery folks, the everybody who would come to your doorstep needs those, right?
Ian: [00:34:26] Yeah. Yep, yep. I wish that more of them would come by bicycle. [laughter] I’d be much more inclined to buy, you know, from online retailers if I knew that they were going to be delivering by bicycle, that’d be super cool.
Bev: [00:34:38] It would be. And the 1% lost local option sales tax that Saint Paul is pursuing in the in the vote this year is not just for roadway reconstruction. It will not go to maintenance at all. It is for roadway reconstruction and park facilities. Okay. Distribution.
Ian: [00:34:58] Interesting that roadway reconstruction is categorized differently than maintenance, because I think of that as a form of maintenance. Right? It’s a it’s a preventative measure. Like, you know, a brand new reconstructed road is going to generate fewer potholes to be maintained than than one that has not been reconstructed for 60 years.
Bev: [00:35:18] A reconstruction fundamentally, is accomplished when a determination is made that the roadway that was in place has met the end of its life cycle, nothing can be done to rehabilitate it, to to return it to any kind of life cycle that is worth the money that would be invested. So when you’re reconstructing a roadway, you’re putting in an entirely new roadway and starting a new life cycle. And that’s why we don’t consider it maintenance.
Ian: [00:35:47] Okay. Yeah. Because what what are the, um, what are the all the different like, levels of, you know, like a mill and overlay is like the, the lightest touch version of, like a, you know, not it’s not even a reconstruction, but like, you know, that kind of maintenance are there? Are there steps in between mill and overlay and like a full reconstruction?
Doug: [00:36:07] Sure. There’s even steps before a mill and overlay. Right. You know, you could.
Ian: [00:36:10] Do all the patching that we were just talking about.
Doug: [00:36:12] Patching sealcoating, where you just essentially put oil and rock on top of the surface. Mhm. Generally after a very good patching job. You know that’s probably the lightest. And then micro surfacing which I’ve done before. And then and then a simple overlay. Don’t even mill. Just put a new topcoat on okay. That’s tough. And that’s that’s and that gets tough in the urban area. You see sometimes that might fill in the gutters. And again you’re then you’re hurting your drainage again. And so that’s something you don’t always do.
Ian: [00:36:50] So is that the kind of repaving that they just did on Summit that like stops right before the bike lane?
Bev: [00:36:56] Yes. We what Doug was mentioning was putting a more substantive layer on which would come into the gutters. The gutters on Summit are gone already. So we were what we call skim paving, which is a very, very thin overlay to to seal up the roadway in effect. And we didn’t do the bike lanes. We patched the bike lanes extensively because the bike lanes weren’t in the same condition as the roadway. And what we were finding is that people were swerving into the bike lanes to avoid the holes in the driving lane. So our goal was to take care of the driving lane and get that sealed up and decently surfaced, and then patch heavily the bike lanes and the locations, the few locations where it really needed it. And that has been entirely successful.
Ian: [00:37:44] Yeah. And I think I remember Sean was talking about like that if, if too much work was being done in the gutter and you know that like all the way out, then ADA compliance was going to come into play and it would have to be like a much more expensive job.
Bev: [00:38:03] It’s if you mill. If you mill normally, ADA must be taken care of before you do the milling and the overlaying. And so we could not mill to do that very, very much Band-Aid work that we did on Summit.
Ian: [00:38:20] And Summit is on the map of like roads that will get a reconstruction if the 1% sales tax passes. Right?
Bev: [00:38:30] Yes. It’s got a lot of complexities with regard to who wants what, for what reasons, in what way. But what I would say for sure is that the infrastructure under the roadway, the sewer infrastructure, and I believe the water infrastructure is old and needs to be replaced. Yeah. And that really does need to happen.
Ian: [00:38:53] Um, I, I kind of interrupted the, the list. So we were at Mill and Overlay and then was there any is there anything.
Doug: [00:39:00] Well there’s there’s reclaim and overlay. Sometimes you’ll instead of just milling off two inches and putting two inches back, if you have six inches of asphalt, you might you might grind the whole thing up, re-lay it and then put a new hot mix asphalt top on top of that. So that gets rid of a lot of the reflective cracking that you might have by just doing a mill and overlay, because those cracks go all the way down through the full depth of that pavement. So if you just mill off two and put two back, that crack is still there and it can reflect back up very quickly. So sometimes it’s a little more expensive. But you know, we’ll grind up the whole pavement and maybe you might have to sacrifice some because then you still got to create room for the new asphalt in the rural, on rural roads where it’s just ditch, you can build up, you know, keep all of that. And but in the urban areas where you’re still matching in to gutters and, you know, manholes and stuff like that, it gets a little more difficult to do something like that. So, so you can do those reclaim and overlays and then then beyond that, it’s considered full reconstruction.
Bev: [00:40:13] There is a step above potholing and before other activities. That’s more of a mill and patch. And while Saint Paul does not have a crew and equipment to do that, MnDOT has done that quite extensively in many, many of its asphalt roadways. And where there’s a large pothole that you know is going to be problematic because of alligator cracking and other things going on around it.
Ian: [00:40:37] That’s a fun name.
Bev: [00:40:38] Yeah it is. It’s like the top of an alligator. It’s it’s all cracky and little squares and things like that. They’ll come in with a small mill, not a full roadway width mill, but something more on the four foot size. And they’ll mill out a patch, and then they’ll make sure the base is good there, and then they’ll put in and overlay and fill in that and pave that. And so it’s sometimes what you see is a square on a trunk highway or something of that nature at the state level. And that’s a mill and patch. And it is a fantastic way of a more substantive repair to a pothole that keeps coming back.
Doug: [00:41:15] And you might do that in situations where. You have a lot of stopping and accelerating traffic. You know, like at a stop sign, you know, you get that washboarding sometimes if you want to, you know, the whole road’s not bad. It’s just where people are stopping and starting. So you might just do a, you know, that mill and patch, you know, in a situation like that.
Bev: [00:41:38] And Doug mentioned before, rutting, it’s hard to notice it if you’re just driving along the roadway. But roadways can develop very significant ruts. And that is not good for drainage. That’s not good for safety, that’s not good for ride, all sorts of things. And so we can go in and just fill in ruts and longitudinally down that roadway. It’s not super common, but it’s it’s doable. And it’s one way to also address some of those roadway conditions.
Doug: [00:42:07] Yeah, I actually won an award when I was a county engineer for our rut paving operations. You know, very cost effective. It looks kind of ugly. You know, you get because the old asphalt is kind of grayish and the new is black. So our roads kind of look zebra like. But but it was very effective. You know, the road typically will have a crown. So water drains from the center to the outside. If you have a rut in there, it can trap that water in there. And so, you know, if you’re coming on a highway at 50 miles an hour and you hit, you know, essentially a trough of water, you can hydroplane and cause really serious accidents.
Ian: [00:42:50] That also, I mean, the lack of drainage is-
Doug: [00:42:52] Again then that’s another way for water to get into-
Bev: [00:42:57] Birth of a pothole. Yeah.
Ian: [00:42:59] Like miniature version of this troughing that I can think of is in my parents’ driveway. They have owned a 15 passenger van since I was like a small child. And of course that van parks in the exact same spot on that driveway. Every time they drive up there, the two spots right above the engine block, you know where those two front wheels with the most weight on them sit for most of the day. You know, when you drive up there in the van, you know, when you have gotten to the spot that you need to when the van goes, [makes descending zhoop sound effect with mouth].
Doug: [00:43:32] [laughter] Exactly.
Ian: [00:43:35] What are some of the impacts of potholes? Like do we do we have numbers on, you know, finances, you know, how much does the city lose? How much do you drivers, you know, like damage to cars and damage to bikes and, you know, injuries, that kind of thing. Um, what kinds of, you know, impacts do do potholes have in Minnesota?
Bev: [00:43:59] Minnesota tort claim law is what I would consider to be very strong in that it requires the agency involved to have known about and had the ability to address a pothole and still had not taken action. And that means that we don’t pay out that often on pothole claims. We we don’t, in my experience and my awareness, get a whole lot of claims from bicyclists or people on scooters or pedestrians. They they can occur. They do occur, but they’re extremely small minority of the number of claims we get. And we have gotten a record setting number of claims this calendar year. I don’t have current data on it, but it’s quadruple or five times more than we would normally get in a calendar year. Understandable because of the number and type of potholes that we had and the fact that the pothole problem started in February and it lasted till about last month. At that rate of claims being made.
Ian: [00:45:13] It’s interesting to think about that, you know, like five times rate compared to the like roughly like three times higher rate that you mentioned of people reporting potholes in the first place, which makes it sound to me that people are more eager to sue the city than reporting a pothole in the first place.
Doug: [00:45:34] Well, and again, you know, Minnesota law doesn’t matter what speed limit sign is up, everybody can only drive a roadway to the speed that you can safely drive. I mean, when we get these freezing rains in the wintertime, you’re not going to the interstate. Says 70 miles an hour. You are not allowed to drive 70 miles an hour, right? Right. You have to drive according to the conditions of the road. And that that includes, if it’s full of potholes in the spring.
Ian: [00:46:06] Is that a defense that municipalities have tried to use?
Doug: [00:46:09] Oh, yeah. Absolutely.
Bev: [00:46:12] We put up rough road signs on Shepard Road and we had to. Because it was. It wasn’t that we were paying out a whole bunch of claims on Shepard Road, but we were tired of people contacting us and saying this pothole, this pothole, because we were filling it as fast as we could. But at Shepard and Homer, where we have an underground water problem seeping water, we literally couldn’t keep the roadway together. We were doing it every day as much as we could, but it was still just creating potholes spontaneously. And so we had to put up rough road signs to get folks to know that they had to slow down and to also protect the city, to say, listen, we told you rough road. We told you slow down. If you came through and had some level of damage that you’re trying to claim, that is your responsibility as an adult driver.
Ian: [00:47:05] How do we repair potholes?
Bev: [00:47:07] Oh, there is so much to get into. It is an art, and the most important thing I would share is it’s much harder to do correctly and safely. When you think about people who are doing this for 8 to 10 hours in a day and the amount of tonnage they go through and the the wear and tear on bodies to do it correctly is an art and a science.
Doug: [00:47:31] In the winter time, you know, that is not your permanent pothole patch. That and sometimes, you know, if conditions are really bad, you’ll do kind of a throw and go, you know, you’re just throwing cold mix in tamping it, you know, and then moving on.
Bev: [00:47:49] And let the traffic come-
Doug: [00:47:49] And let the traffic do the job so that that’s the very bare minimum. That’s when you’re just things are bad and you just got to fill holes and it’s not permanent. But I know Bev can probably go over the, the real way to fix a pothole.
Bev: [00:48:10] And in the summer with the hot mix which has a nice grip on asphaltic cement that is allowed to connect better, better compaction, better sticking, better, better thoroughness closer to actual paving, we just put that in a commercial motor vehicle, a truck, and we’re shoveling that out of the back of the truck. And so that’s why you see different equipment being used in different pothole patching.
Ian: [00:48:40] Okay, so Bev, you have your perfect pothole in front of you. Yes. Uh, on on a lovely street where there’s no traffic coming whatsoever.
Bev: [00:48:49] Well, I’m still going to do traffic control because you just never know. And a really good point would be that everybody who’s in the field doing pothole patching keeps their head on a swivel. Fundamental, absolute truth of anybody doing work in the field. Because you never know where somebody is coming from and you never know what attention they’re going to be paying or not paying attention. And so that’s that’s key. Good traffic control and head on a swivel. All the right personal protection equipment, everything in that zone. So imagine you’re in a crew and you’ve got your protection and you have a truck full of asphalt in front of you, and it’s got a tarp over it to try and keep that asphalt warm. And you have a variety of people working with you. So somebody, not me, has gone ahead and blown out the holes, as I imagine several holes on a street. And so the key is to position that truck with the asphalt in a location that is 5 to 7ft away from the pothole.
Ian: [00:49:46] What kind of equipment do you use to blow out the the pothole? Are we talking like like are they wearing like a leaf blower backpack kind of thing?
Bev: [00:49:54] A bit stronger. Well, there are some leaf blowers out there that are phenomenally strong. But yeah, it’s basically that it’s a backpack blower. Remarkably heavy. But it it does a blast because you want to blast that hole out and get any moisture, any small pieces of loose anything, any dirt, any grit, any anything in that vein, you want to get it out of the vicinity, because the goal is to create a seal in that pothole and around that pothole so that you’re keeping, not only recovering the road surface, but keeping water out in the future so it can’t keep growing. So if you have the truck with the tailgate down with a mound of hot mix right there, you have that pulled in the direction. You’re going slightly in front of the the pothole itself, and the person who is doing the pothole filling with the shovel. They get to direct that truck of where they should go. That’s a key, a key configuration. So if you imagine that the truck is to your left and you are holding a shovel, your normal traditional shovel, so you’re going to have your hands on top of the the shovel pole handle, and you’re going to reach in and you’re going to try and reach in and get to the center of that asphalt pile so that you get good hot asphalt. You don’t want the stuff on the edge. You want to shovel that into the center again so that you get nice, hot stuff.
Ian: [00:51:20] Like penguins recirculating each other back into the group?
Bev: [00:51:24] Beautiful visual image. Yes, exactly. So you want to get a good shovel full of that, and you want to simultaneously. And this is the art because it’s not easy to do. You want to be standing at right angles to that tailgate, and you have your shovel parallel to your hips, and you want to in one fell swoop, you want to pull that shovel out off the tailgate and let your shoulders drop so that you’re dropping it down off the tailgate. You’re not lifting it, you’re just dropping it off the tailgate. At the same time, you want to take a step to the right and swivel your hips, not using your shoulders and your arms. Swivel your hips and at the same time rotate your hands over so you’re tossing the the asphalt patch that’s on that shovel into the hole. And you’re aiming for the, the center of the hole to the edge of the front edge of the hole. But I missed a step because before you’re tossing that in there, your coworker who’s got another container and has a sprayer, they’ve come through after someone has blown out the pothole, they’re spraying tack. It’s a asphaltic emulsion. They’re spraying tack around the edges and the base of the hole. And there are some people who feel strongly you don’t spray the bottom, the base, but we spray the base. That’s our thing. So you spray the edges and the base. And so then I’m coming along throwing that pothole, that hot mix, and you’re tossing it in there. Now there’s another person with a lute or a tamper, either one, which is basically think of a kitchen-
Ian: [00:52:59] Did you say, a lute?
Bev: [00:53:01] A lute is an asphalt paving… It looks like a very short tined, very tough rake. Very short tined, though.
Ian: [00:53:08] Not the musical instrument.
Bev: [00:53:10] Instrument? No, but good on you for knowing that.
Ian: [00:53:14] I like D&D.
Bev: [00:53:17] [laughter] Yes, absolutely. So that that asphalt tack is sprayed and you don’t want it to just sit and get dry. So you want this all to be timed beautifully so you can blow out, you can tack it, and then you’ve got me coming along tossing that asphalt into the hole. Then you’ve got a person with a tamper or a lute, whatever’s available. And they’re, they’re kind of pushing it around in that hole to get it reasonably arched a little over the pavement and to get to the edges and just a tiny bit over the edges. So you get that seal going on. So the key is to make sure you’re getting enough in that hole so that when the roller comes after you, that when they roll it once forward, once back, you don’t need a whole lot when your pothole patching unlike paving. But when they roll it, you’re ending up with something equal to or slightly above the roadway surface. Slightly above is good big above not good, below not good. So it’s it’s truly an art because every pothole has a different depth. And if it’s quite deep, you want to do this in lifts. And so that’s various layers of the hot mix patch. So if you had a four inch deep hole you would want to put in enough pothole mix. And then you’d stamp it with your feet or stamp it with the tamper, which isn’t just doing this. They push it down. They throw it down. You want to do that to get a layer that’s relatively compact, and then you do another layer and compact that, and then you do another layer to get that top seal. So it’s not just a throw and go situation. It’s layers to make sure that you’re getting decent compaction. Because the last thing you want to do is have traffic coming by later on and creating a depression to create a re-pothole.
Ian: [00:55:07] Right, right.
Bev: [00:55:08] So we’re tamping. We’re tamping. And then when we feel like we’re ready for the roller, we move on to the next pothole. And the roller comes through, which is everybody’s seen them, but they probably don’t notice them. It’s just a huge roller with weight and vibration, and you just drive over it and drive back. And that weight and vibration is getting more compaction and getting that fully sealed up. And everybody moves on to the next pothole.
Ian: [00:55:37] There you go, yeah. It’s a, slow, slow walk with a lot of steps in between.
Bev: [00:55:43] And much, much tonnage of asphalt. Hot mix going out.
Ian: [00:55:48] Yeah.
Bev: [00:55:48] Yeah, yeah. It’s a crew of about six people in various roles. And they can rotate to make sure that not just one person is tossing that asphalt all day because it’s it’s hard. Yeah, it is hard.
Ian: [00:56:02] The stereotype when you, you know, you’re out and about and you see like a construction site and you’re like, okay, well, you know, you’ve got like two guys to do the work and then like three to stand around and point at them while they while they do the work. Like, it sounds like this is not that kind of operation at all. There’s all hands on deck. Everybody’s active all the time.
Bev: [00:56:20] Yeah, I guarantee you, the supervisors at the city, and I strongly believe that the supervisors and all sorts of other agencies, when they come back after a day of pothole patching, checking on folks, they step in and do they’re, they’re dirty. They’re tired. They’ve done.
Ian: [00:56:37] Yeah, yeah. Bev and Doug, thank you for coming on the Streets.mn Podcast. This was a delight. You guys have an open invitation to come back any time if you’ve got more fun street stuff to talk about.
Bev: [00:56:49] Such a pleasure. Thank you.
Doug: [00:56:51] Thanks for having us. It was fun.
Ian: [00:56:55] Thanks for joining us for this episode of the Streets.mn Podcast. This show is released under a Creative Commons Attribution Non-commercial Non-derivative license, so feel free to republish the episode as long as you are not altering it and you’re not profiting from it. The music in this episode is by Eric Brandt and the Urban Hillbilly Quartet. This episode was edited by Jeremy Winter and was hosted and transcribed by me, Ian R Buck. Guest acquisition was done by Sherry Johnson with production assistance from Christina Neel. We’re always looking to feature new voices on the Streets.mn Podcast, so if you have ideas for future episodes, drop us a line at [email@example.com]. Find other listeners and discuss this episode on your favorite social media platform using #StreetsMNPodcast. Until next time, take care.