Think Out Loud

Planned tolling for I-5 and I-205 aims to reduce congestion in Portland metro

By Allison Frost (OPB)
Dec. 20, 2022 10:36 p.m. Updated: Dec. 29, 2022 12:22 a.m.

Broadcast: Wednesday, Dec. 21

Interstate 205 runs along the east side of Portland, intersecting several major highways, July 2022.

Interstate 205 runs along the east side of Portland, intersecting several major highways, July 2022.

MacGregor Campbell / OPB


Drivers could be paying a toll to drive on I-5 and I-205 in the next couple of years. The Oregon Department of Transportation is soliciting public comments now for an upcoming study on tolling those freeways. Aaron Golub is a professor in the Urban Studies and Planning department at Portland State University. He joins us to tell us more about what tolls on I-5 and I-205 might look like in the next few years, where tolling has worked elsewhere, and the challenges of addressing congestion along with safety and equity more broadly.

This transcript was created by a computer and edited by a volunteer.

Dave Miller: This is Think Out Loud on OPB. I’m Dave Miller. Drivers could be paying tolls to travel on I-5 and I-205 in just three years. In preparation for this, the Oregon Department of Transportation is asking for public comments right now for an upcoming study on tolling. Aaron Golub is a professor in the Urban Studies and Planning department at Portland State University. He joins us to talk about congestion, safety, equity, and tolling. Welcome back to Think Out Loud.

Aaron Golub: Good afternoon, thanks for having me.

Miller: Before we get to the details, I just want to give listeners a sense for the overall time here because I think it’s important context. The Oregon Department of Transportation is currently seeking public comment, as required by federal law, to get input on the community and environmental issues it should study. And then a year from now, it plans to publish a draft environmental assessment for more public review and comment, but the agency says that the earliest the tolling could begin for this Regional Mobility Pricing Project is late 2025.

So that’s the background. Aaron Golub, can you give us the big picture sense for what exactly ODOT is considering implementing?

Golub: There are really two projects that are kind of intertwined: the I-205 tolling project, and then the regional mobility project, which is the broader I-5 and I-205 tolling project.

Miller: And what could this look like?

Golub: You will, I guess, pass through some kind of gantry at different points along those facilities, and using transponders or possibly other technologies that are still being developed, pay based on the amount of distance you travel within I-205 or I-5, those twin networks there.

Miller: The agency is talking about variable rate tolling. What does that mean?

Golub: Not only will it vary by where you enter and leave the facility, it will also vary by time of day. And the details are not set yet, not only in terms of the rate, but how much it will vary. The point being that during the peak hour you would expect that the toll would be a bit higher than off-peak, and it may be free on the weekends. There will be different times of the week and different times of the day where the toll will vary.

Miller: Is this synonymous with congestion pricing, a phrase I feel like I’ve seen at least as much, if not more?

Golub: Yes, this would be implementing that approach. The basic idea is, when facilities are oversubscribed, very congested, some travelers don’t necessarily have to travel at that moment, but they’re not seeing any financial penalty for doing so, although they are sitting in traffic. The idea of congestion pricing would be to charge drivers a little bit higher at those times, and hopefully some drivers, but not all, would be able to either forgo that trip or make it at an earlier time or off peak, or perhaps shift the trip to a different location locally.

And then on the other hand, other travelers may decide they want to travel during that period because the pricing will allow a more smooth trip. And so they’ll have a more predictable trip. So you could see shifts both ways when you think about it.

But yes, this is a congestion pricing approach.

Miller: The peak times are obviously based on what traditionally has been the work hours for many people. Has the pandemic changed that enough that surge pricing or variable tolling or congestion pricing is less of a meaningful notion? Or is it, for the most part, most people still have to be at work sometime between 8 and 9 in the morning and might leave around 5pm?

Golub: Well interestingly, it is documented that there’s a remaining amount of work at home, and trips have been changed. But vehicle travel is actually back up to roughly what it was pre-pandemic. And so we’re seeing very similar rates of delay and congestion as we did in 2019. Some of the trips that may have been work trips have been replaced with other kinds of trips, and that’s total travel, it doesn’t necessarily speak to the peaking that happens. So you’re right, there may be a little bit less peaking, but I actually haven’t seen that data. But total travel is back up, and I think long term projections are that there could be still issues of congestion, similar to what we experienced pre-pandemic.


Miller: How much has variable rate tolling or congestion pricing, in previous places where it’s been implemented, changed driver behavior in terms of when they are traveling? How much do people actually elect to time shift their travel?

Golub: Well as you’d suspect, it depends on those rates. You can see very high rates in some places where they’re using these approaches, and they see pretty significant reductions in travel. I believe in Seattle there was like a 20-30% reduction in peak congestion following instituting pricing there. You’d see similar declines in other places and shifts to what you might call the shoulder time, so right outside the pricing period or onto other modes.

It’s not known yet what ODOT is shooting for in terms of how much of a reduction they’re going to need. In some of their reporting, they’re I think trying to get at a 45mph “guaranteed” time. Obviously they can’t control incidents and crashes and things like that, which does contribute to congestion. But in terms of the bottlenecks and things that they’re managing on their network, I think they wanna try and guarantee a 45mph trip. I don’t know what kind of charging that would require.

But I’ll just say that just a few percent diverted can reduce congestion quite significantly, because the way the traffic flows work, when they surpass the carrying capacity of the roadway just by a small amount, the travel flow can break down just from minor interactions by vehicles, on ramps and other bottlenecks. So even reducing just a few percent can have a quite large impact on the steady flow of traffic.

Miller: So let’s turn to that diversion, which is a kind of technical term to just mean that people will use neighborhood streets, residential streets perhaps, or neighborhood arterials as opposed to I-5 or I 205. It’s a hugely important question because, just last week, Portland’s pedestrian fatalities reached a 70 year high for this year, 31 people were killed. What could diversion mean in terms of safety on local community roads?

Golub: It’s a serious issue and I’m glad you bring it up. It’s not completely understood. ODOT has done a pretty detailed analysis of where trips would begin and end along the I-5 and I-205 corridor. They’ve been looking at where diversion might happen. But they would need to then work with PBOT and some of the other transportation authorities to do the appropriate traffic calming, and all those upgrades that would need to happen to minimize the impacts on neighborhoods.

I think it’s a serious issue. I just don’t know, in terms of what I’ve read, the details of how they’re going to solve that in every place.

Miller: What could the revenue that is collected through these tolls be spent on?

Golub: That’s a very important question. There are certain parameters on that in state law and federal law, because these are interstate highways. Other facilities like these have been spending them on public transit upgrades, on nearby safety and traffic accommodations near the tolled roadway. Of course, there is an equity component, where some of the tolling can be reduced for low income travelers, and that reduces revenues.

ODOT’s main goal is to help maintain and operate these facilities, but the gasoline taxes have been long not maintaining themselves for inflation. The federal gas tax, which ODOT relies on, has not been updated since the mid 90s, and it’s declined in buying power significantly since then. ODOT is trying to make up for a lot of those lost revenues, and construction costs have been going up. So their primary charge is to maintain and operate these roadways. And so I think principally the revenues will start towards that. And then it can be used for transit in the corridor, and other projects that can help folks make different decisions.

Miller: My understanding is that the state constitution prohibits spending tolling revenue on anything but roadway improvements, so I’m not sure that in Oregon it could be used for public transit, even though the hope would be that some people would be more likely to switch to public transit to for a whole bunch of reasons as one of the ways to reduce congestion.

I want to turn to something you mentioned that is important here. Let me run a quote by you that I saw in the business tribune recently. This was from Dean Suhr, an anti-tolling organizer in West Linn, and he told the paper this: “Tolls aren’t going to offset any congestion, they’ll just price out and burden the poorest drivers.” And I should say that we saw similar comments on our Facebook page.

What could tolling mean for low income people who either would have to pay more or travel further if they’re not going to go on highways, and how can tolling be implemented in a way so that it is equitable and not regressive?

Golub: So this has been an important issue for ODOT since the inception of the project. They’ve been convening an Equity and Mobility Advisory Committee, which has come out with some interesting analyses and some recommendations. Principally, the issue is can you offer lower tolls for lower income travelers? There are many examples of that. And it seems to me that ODOT is planning to do that. And the exact income delineation and the amount of the reduction or the discount is still being discussed. But it’s looking like around 200% of the poverty line will be roughly a cut off, with some number of free trips per week, or some kind of account load per month, which would cover a certain number of trips for those travelers. So that might appease some of the issue. That’s used in other places as a way to to overcome some of the issues related to income, which are really important,

But you have to realize that low income households also have to get to work on time. Many will value that predictability and the ODOT’s guarantee, within their means, to offer this 45mph trip. They have work to get to, they have deadlines to make just like everyone else. If you look at, for example, tolled lanes in other places like in southern California, you will find that yes, low income drivers are underrepresented slightly. But there’s still large numbers of low income drivers taking advantage of the tolled lanes.

Miller: And finally, one of ODOT’s stated aims is to reduce carbon emissions. Has tolling in other places been shown to decrease emissions?

Golub: This of course has to be estimated, and I think the work I saw in Seattle did estimate that there were some pretty significant emissions reductions because of the better traffic flow that reduced stop and go, which is a bad driving situation for emissions. If that 45mph flow can be maintained, I think it could mean pretty significant reductions in both local pollution, and then kind of climate forcing gasses, carbon dioxide. Both of those could be improved from this kind of policy.

Miller: Aaron Golub, thanks very much for joining us.

Golub: Thanks for having me.

Miller: Aaron Golub and urban studies and planning professor at Portland State University.

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