I live in the St. Anthony Park neighborhood on the northwest corner of St. Paul, which is divided by Trunk Highway 280. The highway’s construction in the 1950s caused removal of homes and businesses, and its ongoing presence generates noise and pollution that we all cope with daily. It started out as a somewhat modest connecting route.
How did the highway get to be what it is now — a quasi-interstate — and what role did traffic modeling play?
The Met Council’s Traffic Model
Norman Marshall of Smart Mobility recently analyzed the Minnesota Department of Transportation’s (MnDOT) traffic modeling for I-94, related to the Rethinking I-94 project in St. Paul and Minneapolis. The projections are based on the Metropolitan Council‘s traffic model, which Our Streets Minneapolis acquired through a data practices request.
In analyzing the information, Marshall reports the traffic model overestimates traffic growth, and recommends that our local government units and MnDOT should stop presenting these model metrics or relying on them. They are based on outdated tools, he says: essentially old, less powerful computers. He has documented the problems in forecasting traffic flows in a peer-reviewed paper. Better modeling is possible, and that would allow for better decisions about what to build — and not build.
For those of us who are not experts in traffic modeling, there is another way to assess whether MnDOT’s traffic modeling over time has been correct or not, or whether it has perhaps tended to show an upward direction regardless of reality. That other way is to find MnDOT’s past statements of highway use, along with their projections for increases in use and then compare to what really happened over time.
Highway 280: A Case Study
St. Anthony Park has had a community newspaper for 50 years (the Park Bugle), which has covered the changes on Highway 280 as long as the paper has existed.
In December 1983, a story appeared that reported MnDOT numbers for average annual daily trips (AADT) as 50,000. In July 1990, the AADT was again said to be 50,000, as reported by a neighborhood writer. That writer was concerned about the highway “getting busier” with more heavy truck traffic if changes were made to the nearby intermodal rail yards.
In November 1992, MnDOT project engineer Earl VanBerkom is quoted in a longer article saying the AADT was by then 58,000 and that it was expected to increase up to 1–2% per year. He also said that Highway 280 had 2.6 crashes per million vehicle miles, which was two times higher than comparable roads (that is, divided roads without signals; though 280 was not actually comparable, since it still had some signals). He got into detail about the particular interchanges and intersections. In the last three years, he said, Highway 280 at Broadway had 85 crashes; at Kasota and Como there were 68 each; at Larpenteur, 48; and at County Road B, 34. Adding those together, I get 303; divided by three years, that’s 101 per year on average.
At the time, MnDOT was in the midst of a two-year project to widen Highway 280 by 20 feet to allow for what it called adequate shoulders and to add new guard rails.
VanBerkom went on to say that in 1997 the ramps would be made longer, and the roadbed possibly lowered and moved slightly west. Twelve million dollars was appropriated so far. He is quoted as saying, “Something should be done because it’s a very old road and the traffic’s going to be there whether we do it or not.”
Based on the lack of coverage in the Bugle, I believe the 1997 ramp work he described didn’t happen at that time, and the rest of it never happened; the roadbed was never moved to the west, at least. Instead, a lot of work took place to add sound walls in St. Anthony Park because of neighborhood complaints, though MnDOT resisted it for a long time, and it took legislative action to get them funded and installed. As part of adding sound walls, MnDOT wanted to close entry to the highway from the uncontrolled access streets in Lauderdale, which Lauderdale residents opposed.
In the September 1994 Bugle, Julie Lehr wrote, “Approximately three miles long, Highway 280 opened to traffic in 1958 as a connection between University Avenue and Highway 36. It was never designed as a connector between two interstates (I-94 and I-35).” (emphasis added)
VanBerkom is again the MnDOT engineer cited throughout the September 1994 article, and he is obviously the source of this fact: The highway’s crash rate for its entire length in 1994 was 106 per year. Lehr ends the article with this statement: “VanBerkom said the anticipated accident reduction is 42 per year if the road project is completed.”
In May 1996, MnDOT reps again told Lauderdale officials and residents at its city council meeting that if they wanted sound walls, they would have to give up the uncontrolled access points at Walnut Street, Roselawn Avenue and Summer Street. MnDOT considered them dangerous and said there had been a number of accidents at the intersections each year. Tradeoffs exist, they said, especially the loss of the “sweeping view” from Lauderdale toward downtown Minneapolis. But the noise isn’t good for you, engineer VanBerkom said. According to the article, MnDOT would buy the four vacant lots near Walnut Street and Ryan Avenue as well as the Goodwill site on Como Avenue. There would be no environmental impact statement. Even if the wall didn’t get built, MnDOT hoped to seal the street access points for safety reasons.
In July 1996, the Bugle reported that “Lauderdale rejected the Hwy 280 sound wall and opposed closing the connecting streets to the highway at the city council’s May 28 meeting. MnDOT has the right to close the access anyway.” The article closed by saying the reconstruction was 10 years in the future.
But it didn’t happen. By August 2001, it seemed as though MnDOT had given up on changing 280 in a major way. The Bugle reported that MnDOT had put 280 on the back burner. Frank Pafko, metro division area manager of MnDOT, said there were no plans for expansion. “Grading, surfacing and access management in Roseville and Lauderdale” were said to be slated for 2004, with long-term plans for improvements at Como and Larpenteur avenues not planned until sometime between 2016 and 2025. Nancy Daubenberger — now MnDOT commissioner — was project manager for 280 at this point. She described the future plans as improvements, not expansions. That planned “access management” didn’t happen in 2004 either.
Then the Bridge Collapsed
That all changed when the I-35W bridge collapsed in downtown Minneapolis on August 1, 2007. MnDOT almost immediately made changes to Highway 280 to relieve the expected increase in vehicle traffic. They lowered the speed limit to 50 mph and turned the shoulders into extra lanes between Como and University.
The Bugle carried a brief article in September 2007 that said MnDOT “will resume work on Hwy 280 [after the State Fair ends], adding lighting, traffic cameras and noise reduction measures. The Hennepin/Larpenteur/280 interchange will be modified and temporary stoplights will be installed, median removed on the…bridge over 280. The Broadway, Roselawn, Walnut and County Road B2 access to 280 will remain closed until the 35W bridge is completed. [Then] MnDOT plans to make more extensive changes to the Larpenteur/Hennepin/280 interchange. The bridge will be closed and traffic rerouted during that construction.”
In the same issue, there was a commentary from Gregg Richardson, a member of the St. Anthony Park District 12 board, and Jon Schumacher of the St. Anthony Park Community Foundation, in response to a recent Star Tribune editorial that suggested permanently upgrading 280 to interstate status once the 35W bridge was replaced.
Richardson and Schumacher wrote that while most of us in the neighborhood support the kinds of development mentioned in the editorial, “we believe [it] presents the opportunity to reduce traffic on highways like 280, not increase it.” The editorial looks backward, they said, not forward in the midst of global warming. They made the argument that induced traffic demand exists. If anything, they wrote, add park-and-ride lots in the suburbs and dedicated bus lanes on 280 to reach the Westgate area. Highways cut city neighborhoods into pieces, they said, and we have enough divisions in St. Anthony Park from I-94, the railroads, University Avenue and 280 itself. Increasing the capacity of 280 would increase pressure to increase the capacity of east-west “connections” as well.
They continued: “High-volume highways work against the very things we need to promote: more compact development with greater density that still retains a livable neighborhood feel.” And the Bridal Veil Creek watershed lies beneath and around 280, they reminded readers. “It would be highly ironic if one of the legacies of the bridge collapse was the diversion of highway funds to building yet another counterproductive freeway, rather than repairing dilapidated and dangerous infrastructure or planning for a more rational urban future.”
After September 2007, there was no Bugle coverage of 280 for a few months. If only we in the adjacent areas of the highway could have known that the 35W bridge would be rebuilt within a year (opening on September 18, 2008) and that traffic levels on the highway would revert to their old levels. And that MnDOT’s traffic projections for the future, beyond the bridge period, were wrong. Things could have been different than they have turned out. Instead, this is what happened.
A story in the January 2008 Bugle told about the heavier traffic on 280 since the bridge fell and renewed calls for sound walls. Then-State Rep. Mindy Greiling was quoted saying opinions in Lauderdale have changed, referring to people on Walnut Street, whose back yards abut the freeway: “…they are desperate,” she said.
“MnDOT says traffic counts doubled since vehicles from 35W were rerouted onto 280,” the article continued. Beyond noise, there were also concerns about drivers crashing into a garage or a house in Lauderdale. (This did not happen.) MnDOT engineer Marc Goess said there might be federal money available because of the bridge collapse. Carol Molnau — Tim Pawlenty’s lieutenant governor — was also MnDOT commissioner at the time, and Greiling urged readers to contact her about allocating money. Greiling also argued “that the continual upgrading of Highway 280 should be declared a major project, allowing the sound wall to bypass the statewide waiting list.” MnDOT said it needed to be shown that the St. Anthony Park neighborhood is united behind the request. The St. Paul City Council would act soon, too. Greiling said when the windows opened in spring, “there’s gonna be hell to pay.”
A few months later, the April 2008 Bugle told of a public meeting where 20 people heard a presentation from MnDOT about the noise situation. (Twenty people doesn’t sound like very many, if people are supposedly outraged about noise.) MnDOT’s Chris Roy said they would do an asphalt overlay on the southern portion, despite MnDOT’s skepticism that it would make a noticeable difference in the sound. That treatment couldn’t be done on bridges, though, which constitute a lot of Highway 280 in St. Anthony Park. Sound walls cost $2 million per mile at the time. Construction on a sound wall north of Larpenteur was scheduled to begin in July, in response to the pressure from Lauderdale in previous months.
July 2008 was barely two months before the new I-35W bridge opened. Those walls did get built in Lauderdale, closing the access points permanently and making the road more freeway-like.
There’s nothing in the Bugle for another year until April 2009, when the paper reported that construction on 280 would start on May 1 with the reopening of the Broadway intersection. At this point, the new I-35W bridge had been open for about six months.
The traffic signal at Broadway had been removed in early August 2007 to speed traffic while the I-35W bridge was out of service. Once the intersection reopened, it was not exactly the same as before, though: Eastbound traffic from Broadway could no longer go north on 280. And MnDOT would not restore the signal and entering traffic at County Road B, though southbound 280 drivers would be able to enter the Pacal Business Center on the west side of the highway, located at B.
After that, there was a long, mostly quiet period on the topic of Highway 280 in the Bugle between 2009 and 2021. (It was not quiet on the highway, as drivers appeared to be going faster than ever on the more freeway-like roadway.) The March 2016 issue told of coming roadwork in summer 2016 that would add more concrete median barriers and replace guardrails, while also resurfacing and improving drainage.
In mid-2021, MnDOT again came forward with a proposal to close the left turn lane at Broadway — the last remaining traffic signal on 280 — and to increase the speed limits to 65 mph. Neighborhood opposition, primarily in St. Anthony Park and Prospect Park, delayed both changes until 2026 or 2027.
Currently, MnDOT is once again planning the delayed 2026 project to close the left turn at Broadway for safety reasons, at the same time the highway receives a mill and overlay and most of its bridges are repaired. The project engineer, Chris Bower, says there is no plan at this point to increase the speed limit, though he told the District 12 Transportation Committee there may be a speed study after the project is complete. (If the 85th percentile rule is in use when there’s a newly resurfaced highway with no traffic enforcement, what’s the likely outcome of that study?)
Through all of this, Trunk Highway 280 has not officially been upgraded to the interstate status the Star Tribune editorial board called for back in summer 2007, but MnDOT has worked around the edges to make it into a virtual interstate.
So, has Highway 280 met MnDOT’s predictions for AADT, and have their improvements resulted in the projected number of decreased crashes?
Predictions and Projections
As a reminder, Highway 280’s AADT in the early 1990s was 50,000–58,000, depending on which quoted figure in the Bugle is used. The project engineer in 1992 said the projected traffic growth in 1992 was 1–2% per year.
Putting each of those numbers into a spread sheet, I came up with a table of projected AADTs for 2022 that ranges from just shy of 69,000 to 109,000 per day, depending on whether you start from 50,000 or 58,000, and inflate at 1 or 2% per year:
|50K at 1%
|50K at 2%
|58K at 1%
|58K at 2%
What were the real counts on Highway 280 in 2022?
- At Roselawn Avenue in Lauderdale, it was 41,441.
- At Robbins Street, just south of the rail yards in St. Anthony Park, it was 58,214.
- Overall, the Roselawn counts were similar to or lower than the number of vehicles in the early 1990s.
- The Robbins counts are similar to the counts before the I-35W bridge fell, and all of the counts from the early 2010s after the bridge reopened.
And the 2022 numbers for the Roselawn location is not an anomaly: the annual figures available there from 2004–2021 are relatively consistent with the 2022 figure. The Robbins figures were higher in the late 2010s, but since 2020 so far have not returned fully to their pre-covid levels. That seems like an opportunity to decrease vehicle miles traveled.
And what about the crash rate, given all of the improvements made to the road, which it was said would make it safer? Residents were told in 1994 that the 106 crashes per year were unacceptable, and the planned changes would reduce that number to a very specific 42. I requested some data from MnDOT to find out if those changes correlated with a decrease in crashes.
MnDOT’s crash data between 2004 and 2022 — the earliest year I was given in my data request — show an average of 103 crashes per year. Only one year had fewer than 50 crashes, and that year was still higher than 42. Among the total number of crashes, there were:
- Six fatal crashes in 19 years.
- Six serious injury crashes in 19 years.
- An average of 5.4 minor injury crashes per year.
The crash information does not include how many deaths or injuries were involved in the individual crashes. I also don’t know how the crash rate per million vehicle miles compares to the number cited by MnDOT in the early 1990s; MnDOT did not provide that statistic for more recent years.
There is no apparent pattern in the occurrence of fatal and serious crashes; they have not decreased or increased over time, for instance. There were more total crashes the year the 35W bridge was out of service, as you might expect — though there were no serious injury crashes, possibly because the traffic was moving slower during congestion. (One fatality did occur in 2007, but it’s impossible to tell from the data I received if it was before or after the bridge collapsed.) Other than the increase in total crashes during 2007–2008, no pattern emerges.
Moving Past Traffic Projections
In his book Confessions of a Recovering Engineer, Chuck Marohn of Strong Towns wrote a section on traffic modeling that was excerpted online in September 2021. The Congress for the New Urbanism published an excerpt from that chapter, entitled Every traffic projection is wrong.
A few quotes seem apt:
Instead of accepting that dynamic relations of traffic are unknowable and developing a management approach that does not rely on false projections to provide an illusion of certainty, traffic modelers make their models more complicated and opaque.
The goal of traffic modeling is not to be right; it is to create a plausible narrative as to why more construction is both needed and helpful.
There is no attempt to capture any emergent reaction from a dynamic system.
In 2015, Congress commissioned a report through the National Academy of Sciences that reached the same conclusion. From the report: “The committee concluded that existing [Travel Demand Forecasting] models do not offer the national- or regional-level prediction capabilities needed to assess system level impacts from Interstate investments.”
…it is widely known within the engineering profession that all traffic models are wrong. The conscience is soothed because the profession always seeks better models, and a partially informed guess is perceived to be better than a completely ignorant guess. This known error is accepted because, for the traffic engineer, there is no viable alternative.
The viable alternative to traffic projections, it seems to me, is for public policy makers to have a vision for the community they are elected to help shape, in the midst of the climate crisis we face. Traffic engineers are engineers, and they could be charged with solving the technical challenge of decarbonizing transportation — not trying to maintain an unsustainable system that cannot be maintained as is.
In the case of Highway 280, there has not so much been a push to expand its lane capacity as to increase its speed and so-called efficiency — often in service to the ephemeral goal of safety. That increase in speed has led to more noise and pollution for its immediate neighbors, and a constant ratcheting up of the belief that “the traffic’s going to be there whether we do it or not,” instead of an examination of the status quo.
All this in a city with a Climate Action and Resilience Plan that calls for a 40% decrease in vehicle miles traveled by 2040.