Elasticy of Roadway Demand Illustrated Again

There was a lot of discussion in various media and blogs last week about the traffic jam that didn’t materialize when I-5 was severely limited during construction in the Seattle area. Demonstrating once again that all those drivers apparently do have real choices. Either the trips really weren’t vital, or they have other options. Here’s a column from a Seattle paper, quoted on the Pricelines blog:

The short answer is that this is always what happens….

In 1998, British researchers studied what happened to traffic in more than 100 highway and bridge shutdowns in Europe and the U.S. They found that on average 25 percent of all car trips simply evaporated.

People still went to work. Some commuters drove, some found another way in. Some other trips were just not made.

“Drivers are not stupid,” (Oliver) Downs says. “They change schedules. They don’t take some trips, or they delay them. The net effect of all these little decisions can be dramatic.”

There’s that word again. Is it me, or does “little” keep rearing up when the subject is our big problem, transportation?

Seattle’s primary transit corridor, the downtown bus tunnel, is closed. Gridlock was predicted. We dodged that by doing a “thousand little things,” such as moving bus stops and banning cars from Third Avenue.

Now we have closed part of our largest freeway. Still no gridlock. You drivers made sure of that. You did “fifty thousand little things.”

Yet all the plans for what to do next are big. Build big rail lines. Bigger roads. Paid for by the biggest tax increase.

Maybe some answers to our traffic mess are little ….

This is not limited to the Seattle region. Recent local examples include the diversion of West Burnside for sewer construction and major maintenance on the Interstate Bridges.

22 responses to “Elasticy of Roadway Demand Illustrated Again”

  1. This sort of takes the wind out of the “what about the poor people” argument against congestion pricing. There are a thousand little things they can do to avoid the toll.

  2. This sort of takes the wind out of the “what about the poor people” argument against congestion pricing. There are a thousand little things they can do to avoid the toll.

    I don’t think it shows that at all. It shows that there are things some people can do to avoid the toll. But it is likely, that it is the rich who have the most options. The low wage worker who punches a clock can’t decide to arrive at work at 10:00 and leave at 8:00 after a business dinner. The guy in the executive suite likely can.

    Congestion pricing is only the answer if the money is used to pay for better alternatives for those who can’t/won’t/don’t pay the toll. In Oregon, I don’t think that is possible. It would work on the I5 and I205 bridges because the toll could be collected in Washington.

  3. This reminds me of the Interstate Bridge partial closure 10 years ago. Most of the traffic simply wasn’t there. I heard that buses and trains went empty (Amtrak offered free rides between Vancouver and Portland, if memory serves me correctly), everyone was “congratulated” for the effort, and the contractor finished early.

    If we’re going to talk about this type of thing, let’s also remember the retail companies that have locations all over the area, and those workers don’t necessarily work at the closest location – I’ve known people that had to commute across town just to go to work at McDonald’s or Fred Meyer, because they were either transferred to another store or it was the only one offering a promotion.

  4. Congestion pricing is only the answer if the money is used to pay for better alternatives for those who can’t/won’t/don’t pay the toll.

    I’ve always been in support of this idea. I really do think it would work in Portland, but the debate is where? Just the major highways? Highways and county bridges? Certain surface arterials, too? Also, charge only in the peak direction? – or both directions during peak periods? (a case could easily be made for the latter on Hwy 26 between Portland & Hillsboro)

    Provided ample park & ride lots are located near to frequent service bus routes and MAX stations I think this could work quite well. It would also generate a bunch of money to upgrade and expand the bus fleet and bus service in general, since rail routes are not so prevalent here as to be convenient for every corridor. Bus enhancements are frequently being called for by Erik and others on this site and bus riders would likely be the biggest winners in this scenario.

    It’s hard not to like what this could do for all modes transportation in this area.

  5. The money should not be used for those who can’t pay the toll. We should be happy that they are not using expensive, valueable highway space for more productive uses. Until we stop treating highway space as “free” it will always be overutilized.

    I, personally, like HOT lanes where transit can gain a nice speed advantage and the empty spaces can be made available to those who are willing to pay.

  6. I think there are some misleading statements being made here, or at least implications.

    The first and biggest factual error is about the metro bus tunnel; this only affects a number of bus lines (when restored, only about 10-20 lines will run through it) that run in downtown Seattle, and not only does it have no bearing on the discussion, it’s been closed for a good deal of time now to allow construction of a light rail line through it.

    Secondly, it’s implied that there was no impact on traffic during the I-5 closure. As someone who lives in the area, this is patently false. I-5 was a mess, and the side effects of the closure were felt all over the place… 405 started clogging earlier and harder, for instance, as well as Lake City Way, which runs parallel to I-5.

    Lastly, while it may very well be true that there was a reduction in trips made, there seems to be an implication that this means that overhauling and enhancing the transportation system in the area is unnecessary, which is completely false. What this shows is that we need to *strengthen* these systems and properly educate people about their benefits.

    There is also a good deal of ambiguity around the term “unnecessary trips.” If traffic is normal, you’re a mother or father, and you need to get groceries to cook for your family that are coming home soon, you’d run out and grab them. If your main way of getting there is closed, you may simply postpone and force them to eat on their way home or eat later. This trip would have vanished, but is it unnecessary?

  7. yea, probably unnecessary.

    a community that requires an interstate trip for evening groceries has a problem.

    the solution isn’t another interstate lane, its a local grocer.

  8. There is also a good deal of ambiguity around the term “unnecessary trips.”

    I think that is correct. Most trips, other than to the emergency room, are probably at some level “unnecessary”. But we are talking about low-value trips, that is low enough in value to the person taking them that they will choose an alternative.

    Here is a link to the original column. It appears that there were actually places where traffic improved, much like the Portland region experience with the I5 bridge.

    This is really not as counter-intuitive as it sounds. Taking away road capacity reduces the amount people drive which reduces traffic. And the effects of that reduced traffic are observed not only where the capacity was eliminated, but everywhere along the routes those trips took.

    The flip side of that is that adding capacity adds to congestion all long the routes the additional trips take.

  9. @george: I never said that a new interstate lane would solve anything, it only worsens the situation. Proof: look at 405. The construction is horrible for traffic, and there isn’t any possible way that lanes can expand fast enough to meet new automobile demand.

    The solution is more, better alternative. we have the fifth largest bus system in the country…. oh wait, those still run on roads. Plus, the eastside, especially the Woodinville region, is far too spread out to be effectively serviced.

  10. Wait a second…

    Trips that you are unwilling to pay for are unnecessary.

    Consider back when bandwidth was limited and long distance cost less after 5pm or 11pm than during the day. People got dial tones under that system even though supply was constrained (similar to the highways today). People who were calling to “just talk” waited until after 5pm and those doing business, calling the hospital, etc. paid the toll and talked during the day. In 3rd world countries where the government controled the phones and did not have congestion pricing, people waited for hours to get a dial tone.

  11. clint, i was just being coy!

    i am peering out my work window right now, looking at the construction of a new market. its constantly on my mind. and yea, its gonna save the city of portland all sorts of auto trips.

  12. There was an excellent opinion piece in the NYTIMES in the past year about a woman who lived in Manhattan and would drive her car back and forth across some of the bridges – all day long – just to get that feeling of being on the ‘open road’ she had when she lived back in Kansas (or wherever she was from).

    She said she did at least 10 or 15 loops in a day, so imagine how much extra traffic that one person added. While not particularly popular in New York, there are a lot of people who just ‘cruise around’ in their cars to be cool. And the soccer moms who drive to the grocery store and back. Then drive to the dry cleaners and back. Then go to pick up their kid from school and back. Then drop their kid off at sports practice and back. Etc… trips that could be chained together to save an immense amount of time, gasoline, and congestion.

  13. When our kid was younger my wife regurlarly drove the I-405 to I-5 loop around downtown several times to get induce sleep so I know it happens here too!

  14. That’s a good two and a half hour loop. Surely a trip around Duvall would be more soothing and reasonably long?

    Either way, my main point has been lost in all this nitpicking over what I already knew was a weak example of my point.

    Extenuating circumstances blocking off a major freeway doesn’t justify a lack of development in transportation, both public and private. When forced into a situation, sure, people can make do for a month. However, when it comes down to a day-to-day basis, people here just don’t feel like there are any alternatives to their daily routine, nor have they explored possibilities, and therein lies the problem. The problem, in turn, lies in both a real and percieved lack of options, depending on the circumstances and requirements of each individual.

    Extenuating circumstances aren’t a valid creation of daily routine, because people just aren’t programmed that way.

  15. Clint, I think your comment also helps explane the “induced demand” that people say freeway capacity brings. If people can safely and conviently go on the freeway they will stop driving down my residential street while drinking coffee and talking on the phone . They, my dog, my kids and me would all prefer if they were on the freeway. People are making due with insufficient capacity but they shouldn’t have to.

  16. “there are a lot of people who just ‘cruise around’ in their cars to be cool.”

    When I was learning to drive, I’d try to go out at 5pm because it was far more educational than any other time of the day. However, for the most part our freeways aren’t that bad, so I got bored with that, and I started driving circles through the airport passenger pickup area. (My mom hated it, but my dad refused to let me go there when he was in the car, so…) Just remember that the next time you go pick someone up at the airport: some of these bozos that won’t let you in/out may not even have licenses yet. :-)

    However, Clint’s point, (and I do have to agree somewhat,) is that you wouldn’t use a power outage as an example of people’s ability to converse electricity. When a landslide hit 26 a few months ago, a lot of my coworkers telecommuted, and the weekly staff meeting that was normally held that day was canceled because there wasn’t enough people in the office to justify having it, (although the conference room phone can do a conference call just fine.) Work got done by everyone, it wasn’t a big deal. However, we do need to have a staff meeting once in a while, so you can’t assume that just cause the office can function with only half the people physically there one day, that we could do it on a long term basis… We probably could, but my point is that that conclusion doesn’t follow from a one day example…

  17. Matthew is right, if people had to pay for the road capacity to get to the staff meeting they might demand a teleconference every other week.

    I know I am beating a horse here but it is crutial that we stop treating lane space as free.

  18. …it is crutial that we stop treating lane space as free.

    Bingo! The roads might be there for public use, but we need to encourage people to be smarter about the way they choose to use the roads (i.e., the multiple single purpose trips for the “soccer mom” from comments above). This means charging for their use, to discourage multiple trips that can be consolidated. Of course, the personal freedom nuts are going to suggest that we’re impeding their ability to do as they please or trying to keep track of their whereabouts, but just like in 1859, you can walk anywhere you want without paying a toll (unless you wanted to cross a river, hmmm… why is this free now?) or crossing through a “checkpoint” (except at federal border crossings, just like today). Also, the anti-tax nuts are going to scream that they already pay $54 every other year for vehicle registration (pretty inexpensive for a luxury; I spend more than that on a haircut once a month) plus less than a quarter for every gallon of gas (which I will insist has no direct relation to how much one actually uses the roads), so why should they pay anything more to use infrastructure (that is very costly to maintain) than they already do?

    I do think it is vital to use that revenue to both maintain the tolled – sorry, value-priced – roadways and enhance the alternative offerings that are available (including – primarily – buses, to get transit closer to where people live/work). I’m all for streetcars in densely populated neighborhoods (Hawthorne, SoWa, Pearl) and MAX or commuter trains for long-distance or cross-town runs, but given the density of most of the Metro area we should be trying to saturate bus service in areas that don’t have it and keep the fare low to its encourage use. A lot of people that would ride the bus still don’t want to walk a quarter-mile or more to get to a stop, and if they have to get in their car to drive to a park & ride they’re just going to drive to their destination.

  19. If people can safely and conviently go on the freeway they will stop driving down my residential street while drinking coffee and talking on the phone .

    I think the opposite is actually more the case. People have to get to freeways and they use local streets to do it. But rather than the entire network, they are limited to the few streets that provide access to the freeway. People don’t use neighborhood streets instead of freeways, they use them instead of those local arterials.

    You can see the same impact from the streets that cross the bridges over the Willamette in southeast Portland. Division and Stark, which don’t cross the river, have less traffic than Powell, Burnside, Belmont and Hawthorne that do. And people sometimes use Salmon to avoid Hawthorne, but not because they can’t get on the Banfield.

  20. So you think new freeway lanes fill up right away because people take trips they wouldn’t otherwise have taken?

  21. So you think new freeway lanes fill up right away because people take trips they wouldn’t otherwise have taken?

    At one level, yes. Although its more complicated than that. Its not just more trips, but longer trips and trips at different times. By the time a road is fully congested people have adopted all sorts of strategies to avoid its congestion.

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