Academic papers, specifically. A few have crossed my desk that I think are worth sharing.

car park 4
Parking, photo by flickr user Tim Caynes.

This paper, using a field study from King County, finds the correlation between parking use and a 100 different factors including pricing, supply, transit access and more:

The parking utilization data was correlated with the 100 factors. Independent variable relationships were assessed for their predictive powers using linear regression methods. The results showed a clearly evident and statistically relevant variation in land use to multifamily residential parking utilization. A similar relationship existed between multifamily residential parking utilization and transit access. The relationship between the price of parking and parking utilization showed utilization declining as the percentage of parking cost to rent increased. The overall findings indicate that walk and transit access to trip destinations, block size, population and job density influence parking utilization, in some cases by as much as 50 percent. Most important, the research demonstrates that higher supply of parking appears to consistently correlate with greater parking demand. By verifying intuitive perceptions with data and fact, this research provides a new tool for use in considering the proper provision of parking.

Emphasis added. As I’ve said before, simply the existence of parking is the single most important factor in determining whether people will drive or not. So newer, bigger buildings with more parking are less green that smaller, older ones with no parking.

Los Angeles Metro Subway (Red Line) Entrance, Hollywood & Vine Station
Los Angeles Metro Subway (Red Line) Entrance, Hollywood & Vine Station. Photo by flickr user JoeInSouthernCA

In this paper Michael L Anderson uses econometric models and real life data to show that transit reduces congestion by a much larger amount than previous estimates have shown:

Public transit accounts for only 1% of U.S. passenger miles traveled but nevertheless attracts strong public support. Using a simple choice model, we predict that transit riders are likely to be individuals who commute along routes with the most severe roadway delays. These individuals’ choices thus have very high marginal impacts on congestion. We test this prediction with data from a sudden strike in 2003 by Los Angeles transit workers. Estimating a regression discontinuity design, we find that average highway delay increases 47% when transit service ceases. This effect is consistent with our model’s predictions and many times larger than earlier estimates, which have generally concluded that public transit provides minimal congestion relief. We find that the net benefits of transit systems appear to be much larger than previously believed.

This has always made sense to me, because transit tends to be most highly used to go to and from places that are the most congested.

More below the fold.

Countdown Crosswalk
Countdown Crosswalk, photo by flickr user Lore

Last, this from Sacha Kapoor and Arvind Magesan (pdf) suggests it’s good to inform pedestrians of amount of time before a light changes from green to red, but bad to inform drivers:

Most empirical studies on the role of information in markets analyze policies that reduce asymmetries in the information that market participants possess, often suggesting that the policies improve welfare. We exploit the introduction of pedestrian countdown signals – timers that indicate when traffic lights will change – to evaluate a policy that increases the information that all market participants possess. We find that although countdown signals reduce the number of pedestrians struck by automobiles, they increase the number of collisions between automobiles. We also find that countdown signals caused more collisions overall. The findings imply welfare gains can be attained by revealing the information to pedestrians and hiding it from drivers. We conclude that policies which increase asymmetries in information can improve welfare.

It makes sense, as drivers see the seconds counting down, they speed up to try to make the light.

Let me know in the comments whether you like this post, if so, I’ll do more of these from time to time.

48 Replies to “From the Papers”

  1. You say %1 ride public transit, but what about in has to be higher?

    Also I can understand the “forcing” issue of a small amount of cars having a big effect though I am having trouble imagining the real world situation. For example if transit went on strike in King County, does everyone in Ballard try to drive to that the congested route? Or does I5 become even worse from people not taking Sounder?

    1. Both, I would guess. The big advantage of a car is that it can go many places. With today’s information society, a smart driver can avoid areas that are heavily congested. But there is a lag time. So, a driver in Ballard knows that 15th will be a mess, so she switches over to Aurora. By the time she gets there, it is a mess. It’s too late, though, and she is stuck in it. However, some guy In Wallingford who usually takes Aurora decides to switch over to I-5. The freeway is often moving near capacity anyway, so that pushes it over the edge and it slows to a crawl. Next thing you know people are driving various surface streets and the entire thing is mess.

      On a somewhat related note, a lot of folks (including me) wanted to see the viaduct replaced with surface and transit improvements. However, this got spun as “do nothing”. I would consider “do nothing” to be a fourth alternative (over a tunnel, a new viaduct, and transit/surface improvements). The idea of “do nothing” however, sounded pretty stupid when they closed the entire viaduct for a couple nights last year (or was it the year before). It turned I-5 into a parking lot. This caused 520 and I-90 to be stuck. Which, of course, greatly increased the number of cars going on 405, etc.

      Sometimes drivers adjust, and simply go a different direction. But other times, drivers just put up with it. Until recently, 520 was like that. Extremely slow, but because it was at just the right location, often worth the wait (to very patient drivers).

    2. Everything gets congested. Ballard to Downtown probably survives better because surface streets handle congestion better than freeways.

    3. Remember that not everybody’s destination is downtown. If Metro went on strike, the 44 to the U-District and the 40 to Northgate, Greenwood, and Fremont would also shut down. The 44 is one of Metro’s most-used routes, such that it’s one of the few crosstown routes to have 15-minute service at 10pm. So a lot of riders would switch to cars and fill all the streets out of Ballard. 15th W and Aurora are high capacity (although they’re full at rush hour) but the streets going east are not, and would have long lines at intersections. The 45th corridor has a lot of young athletic people, so they’re likely to bike or walk to Wallingford or UW if that’s they’re destination, so there would be a crowd of pedestrians on the sidewalks, perhaps overflowing them. The Burke-Gilman is already congested at rush hour, and the streets will be full with an unusual number of drivers, so there would be a bicycle traffic jam too.

      If Sounder were closed due to a mudslide (this may sound farfetched but it might happen someday), most people would take ST Express but some would drive. If both Sounder and ST Express were inactive, people would have to drive. (Or stay home. Or take local buses if they’re running.) But a Sounder train fits only as many people as a few buses, and it only runs a few times a day, and they’re spread out over such a large area, that it wouldn’t have as much impact as shutting down Ballard’s buses. At worst it would be a few hundred more cars on I-5 and around office buildings. But since each driver leaves at a different time, they would be all spread out along I-5 rather than a knot at one place.

      Also keep in mind is that transit riders disproportionately ride downtown, not because it’s their destination but because it’s the only place they can transfer. These people would choose different routes if they’re driving/biking/walking, so their impact would be more spread out and diffuse than if they all drove their car on the same route as the bus.

    4. Re the Viaduct: sort of. The people who supported the tunnel thought that the minimal acceptable solution was 40 mph without stoplights, and many of them probably falsely assumed it would be 55 mph. So it’s not exactly that a surface boulevard would do “nothing”, as that it wouldn’t meet their minimum requirements. Many of them probably imagined it would end up being as slow as 4th Avenue, which is what Viaduct-users are trying to avoid.

  2. Old, small buildings with no parking are greener than new, large ones with some parking… in a vaccuum. If you refuse to build anything new in places with great regional transit access, and demand for all kinds of indoor space is satisfied by freeway sprawl with loads of parking and lousy transit access that’s a very poor outcome.

    1. I worked on Capitol Hill (Pine/Broadway area) for a long time, in an old, small building with no parking from the 20s. Despite a lot of the buildings in the area being very similar at that time, there were still a lot of people that drove (I took transit to the Hill, because I’m a sado-transitchist).

      While street parking was expensive and had 2 hour limits, there were plenty of pay lots within a 5 minute walk, most of them very reasonable (~$100-150 per month or $5/day with early bird), considering our proximity to downtown.

      So I would say your statement is entirely accurate. In theory, the Pine/Broadway area should be green in practice, but because of the crummy rush hour transit problems back then (my work moved about a year and a half ago, so I don’t know if transit has changed much up there since then), there was a big enough demand for parking to necessitate all the lots that were there.

      1. On a fairly tangential note, this sort of story is why people that say, “Light rail to Cap Hill will just convert bus users to train users,” are wrong. Light rail to Cap Hill will make it way more accessible on transit for people that work or visit there and aren’t masochists.

      2. “…because of the crummy rush hour transit problems back then … there was a big enough demand for parking to necessitate all the lots that were there.”

        Paid surface lots in urban areas are pretty much a temporary land use. Their pricing says a lot about both the demand and supply sides. As you note, the demand is there in range of $5 per space per day. This isn’t enough to pay off any sort of capital cost, but it makes it worth the property owner’s modest effort to contract with an operator to get some money to help pay the property taxes.

      3. And just think how much more successful it would be at doing so if it had actual urban stop spacing, rather than a single station located where it hardly makes a difference to most!

      4. While street parking was expensive and had 2 hour limits, there were plenty of pay lots within a 5 minute walk, most of them very reasonable (~$100-150 per month or $5/day with early bird), considering our proximity to downtown.

        That’s what I call “the existence of parking”. If there’s parking, people are going to drive.

      5. If transit is terrible, those who can afford to will continue to drive even if parking gets scarce and expensive. Then you get a class division even starker than what we already have.

        You need to incentivize with transit that works and that isn’t a repulsive liberty-hobbling black hole for your time. Having less plentiful parking is important as well, but it only goes so far.

      6. People drive because they can afford to and it’s the American Dream. Even in San Francisco and Chicago there are people who drive from one station area to another, even when there’s a one-seat train or bus practically door-to-door. New York is the only American city I’ve seen where people don’t do that as much. So yes, Capitol Hill has a lot of drivers and parking demand in spite of its density, but it also has a lot of transit riders. You coud run the buses every five minutes and add a Melrose station to Link, and there would still be lots of cars and tight parking. But there would also be more transit riders, higher satisfaction with the transit system, more people coming to the neighborhood, and those who do take transit would use it for more of their trips.

      7. That’s what I call “the existence of parking”. If there’s parking, people are going to drive.

        It’s not just existence of parking. It’s the existence of cheap parking that does it. At $5, parking is the same price as a round-trip bus ride. My house in Seattle north of the ship canal is less than eight miles from Pine and Broadway. Google estimates I can make the drive in 20 minutes, or a bit longer at rush hour. By contrast, a bus ride would take an hour or more depending on how well my departure times and transfer times line up with the schedule.

        Assuming I have a car already, why wouldn’t I want to drive that trip? I would have an extra hour every day not moving from one place to another. Since parking is the same cost as busing the overall cost difference is only the price of gasoline and maintenance for a 15-mile round trip.

        Now, downtown is a different story. Looks like the going rate for parking there is $200-400/month (average of $10-20 per work day). The cost difference for driving is greater, and the design of the bus network makes the time difference for getting downtown smaller. Some people still find that driving is worth the cost (especially those coming from farther away), but many more people choose to use transit.

        When you let developers decide how much parking to build for themselves, the market rate for parking will naturally float upwards and more people will decide that the best option is to use transit.

      8. @Eric: I am not that knowledgeable about Seattle parking, but I’d guess a lot of daily downtown drive-commuters average less than $10/day for parking by arriving early, knowing where to find cheap lots, being willing to walk a little, etc. Also, many have employer-subsidized parking, or an arrangement to pay for parking pre-tax. That’s how it is in Chicago, at least.

      9. Mike,

        The issue is that that San Francisco and Chicago networks have many well-understood deficiencies and known reliability gaps that may affect your possible subsequent trips, even if your initial trip is well-served and “practically door-to-door”.

        While nowhere near as troublesome as in Seattle, the reasonable likelihood that other places you may need or want to go at a later point in your day will be a total pain to reach on transit is justification enough not to bother with transit in the first place, to drive to begin with, to view the car as your marker of freedom-enabling status.

        As we hashed over to an agonizing extent in the recent “Will Douglas doesn’t want to transfer” thread, it almost doesn’t matter how well you serve one specific destination. No non-automaton wants to be told that that one destination is the only place they’re going to want to go in a day.

        Until a reasonable expectation exists that most of the places one would even consider going on a whim or a moment’s notice, within the contiguous urban area, can be reached easily without a car, you’ll have the SF/Chicago problem you describe. Arguably, most of New York City, much of Boston, and swaths of Montreal and Toronto are the only places in North America where this is the case for a critical mass of residents. Even D.C., with its smashing success in inducing transit commutes, is a mixed-bag when it comes to actual transit freedom overcoming an auto preference.

        It’s not about “cars as the American Dream”. It’s about having one life and wanting to live it!

      10. DP, I’m talking mainly about a single round trip, not a chain trip or the fear that you might decide later to make a non-transit-accessible stopover. I’ve seen people drive from 24th & Capp to Montgomery (SF) and back, and from Rockwell to Fullerton (Chicago) and back, and from 6th & Wall to 95th & Aurora (Seattle) and back. In some cases, the people are well aware there’s a frequent one-seat somewhat-rapid ride a block away because they take it sometimes. In other cases, they rarely take transit so they don’t even know, or even if they have a vague idea of the subway line it’s irrelevant to them. I don’t see this nearly as much in NYC.

      11. Right, and I’m telling you that most people don’t like to view their lives that way.

        You may wind up only making that simple round trip, but you don’t want to be required to.

        People like freedom. People like spontaneity. People like the option to change their plan.

        Frankly, I’ve long suspected that the surprising number of young people in Seattle who do rely primarily on no-spontaneity-allowed KC Metro is why we have so many young people who self-define by career and little else, why we have such scant urban activity on weekdays, why many under-30 types are unaware of the world outside Capitol Hill, and why everyone seems to know so much more about the hot TV shows of the moment than they do in other places I’ve been.

        Because we’re a city whose transit inculcates a habit of going only one place, and then going home.

  3. The Pedestrian countdown signals study is interesting. When I drive, I do look at this as an indicator of when the light’s going to change and slow down or speed up depending on the situation distance etc. The other factor is remembering which lights actually do change when the counter goes to zero and which ones don’t.

    1. The light on 17th and Market in Ballard has an extra second of green after it counts down to zero, which I always found weird but use to my advantage when biking or driving.

      But anyone who hasn’t sped up to make a green light thanks to a ped countdown has either not driven or is a horrible liar.

      1. Yes, because driving inherently means you don’t care about the law or other’s safety, and automatically considerer your ability to make it through a stale-green paramount to everything else.

        While some would probably love to tie driving with automatically being an asshole, correlation does not equal causation.

        As for the delay between the ped signal hitting zero and the light turning green, this is generally an intentional choice in pedestrian heavy areas, as it gives turning a cars chance to turn after the intersection is (supposed to be) clear of pedestrians, but before the light turns red. Kind of like a leading interval for pedestrians (where the Ped. signal turns to walk before the light turns green), but for cars.

      2. I wasn’t implying anything about drivers being dangerous or assholes. I’m guilty of speeding up to make a greenlight and I was implying that all drivers are guilty of it at some point in their driving career, no matter how safe and sane they normally drive.

        Unless you are going way significantly over the speed limit or run a red light, I wouldn’t call it dangerous or asshole-ish in anyway. Illegal, yes, because you are probably going over the speed limit, but usually it’s going just fast enough to be the difference of an almost yellow, green light and a full on yellow light.

      3. Will,

        Actually, correlation is causation in this case. But it’s not that assholes drive more often (the “obvious” conclusion). It’s that drivers become assholes because of the constant cheating. It’s a common human trait; when we see our fellows cheating we cheat more.

        If traffic fines had teeth — like $500 for driving in the HOV lane; $1,000 for running a red light (that really does KILL people now and again) and $50/mile per hour over the limit — there would be less opportunistic cheating, and the whole system would function better.

        I’d even take the breathtaking step of giving cops a small (5%) commission on moving violation tickets so they’d be more vigilant and less on the “driver team”.

      4. @Anandakos: I’ve heard of studies suggesting that, regarding DUI prevention, increasing penalties doesn’t seem to help much, but increasing the odds of being caught does.

        Also, given many cities’ experiences with giving police incentives to make more arrests in the form of quotas, I can’t imagine a police incentive system working. Generally people that believe society’s laws are applied in a fair, uniform, impartial way are more likely to behave pro-socially. Giving the police incentives for tickets and arrests probably erodes fairness, and certainly erodes belief in fairness. Generally we allow drivers to get away with too much, but trust in the rule of law is a deeper issue than that.

        Based on similar theories to those suggested by the DUI studies, I’d suppose that consistent enforcement of laws would clean things up. The legislature made its intentions clear through the VUL that irresponsible drivers that cause collisions shouldn’t just get away with it… but they still are. In the past few years the justice system and media have made examples of a few grossly reckless drunk and hit-and-run drivers, but have generally not made much of lesser cases the VUL is supposed to cover. Not with massive shaming and draconian punishments, but with constant reminders of the responsibilities we’re all supposed to have on the roads.

    2. Since moving to Seattle I’ve started checking pedestrian signals, though mostly they tell me when to slow down, not speed up. When driving in fairly free-flowing traffic the regular traffic signals are fine. But when you’re moving much slower than the speed limit, an additional signal can be nice:

      – When biking uphill there are some intersections where you can easily enter on green and not clear the intersection by the time cross traffic has a green light (Northbound Fremont Ave at 39th is awful in this regard). A walk countdown tells me how much time I really have. I really don’t want to get caught in the middle there, so I almost always use the extra information to slow down.

      – When driving slowly in congestion, the flashing hand is an early warning the light will change soon, so I’m extra careful not to enter an intersection if there isn’t a full space for my car on the other side.

      1. Cycling north on 9th, crossing Mercer, the ped signal is disabled during construction, which means no warning of a yellow light. I can’t tell you how many times I’ve entered on a green light, only to have it turn yellow before I’ve crossed the first lane, then proceed to pedal for my life to cross the rest of the 100 ft of road while drivers are itching to go once their light turns green.

    3. I also found this one the most interesting. Are there existing ways to asymmetrically provide this information to drivers and pedestrians? It seems like a challenge, given that they’re looking at the crosswalk signal from essentially the same viewpoint.

      1. Would it help to put fresnel lenses on the countdown signals? If their line of focus were aimed directly at the pedestrian crossing, or slightly to the right of it, it might be difficult for drivers to see them.

  4. As everyone has said, these are great. I do concur with the critique that parking-free buildings are greener than parking-intensive ones, given the same number of units and the same footprint. I’m not so sure that’s the case if the number of units is different.

    1. Read the study and come back. If there’s parking, people drive.

      Or are you saying there’s some other definition of “green”?

      1. I think Martin’s point is that you have to take the number of units into consideration.

        Say you have a lot near a train station. Would a 10 unit townhome complex with zero parking be more green than a 50 unit apartment building with 10 parking places?

      2. Maybe I wasn’t clear. Looking at units by themselves is not sufficient to know whether a building is “green”. You have to look at units and parking.

        Say you have a lot near a train station. Would a 10 unit townhome complex with zero parking be more green than a 50 unit apartment building with 10 parking places?

        Basically, the literature shows that the number of people driving is equal to the lesser of the number of people and the number of parking spaces.

        I think the 10/0 v 50/10 is an unrealistic comparison, just because no one is putting up buildings with 20% parking. Say you have a 50 unit apartment building with no parking. You want to build a 200 unit apartment with 150 parking spaces. That’s the same number of walkers/transit users in both cases.

        In practice, the ratio is usually 80%+. Even in Capitol Hill and Belltown new apartments buildings often have a 1:1 ratio of parking to apartments.

      3. You also have to look at how it impacts who uses the building. If there’s no parking, drivers go elsewhere to live or work or shop. Non-drivers don’t have that disincentive, and probably the building is in the most pedestrian-accessible/transit-accessibe area (otherwise it would have parking), so over time they will tend to fill it.

        Seattle is taking small steps toward reducing the parking minimums in urban centers. Isn’t that lot next to Mt Baker station going to be a building without parking?

  5. Great post, and seeing more would be awesome. Learning about primary sources like this is really, really helpful.

    One other thing worth noting is that parking-free buildings are also much cheeper to build – cost savings that can be passed on to tenants in the form of more affordable leases, be it for housing or commercial use (or both). Obviously, one would expect apartment dwellers to be more car-free friendly than a business, but only because many business owners seem to have a belief that free and abundant parking (something of an oxymoron) is the only way to secure customers.

  6. Very worthwhile post. Though I admit the stats/numbers get my brain all confused from time to time, the overall premise is spot-on.

    Would love to see more.

  7. Isn’t this just a reiteration of the supply and demand curves from Econ 101? I don’t see what is groundbreaking here.

    1. Supply and demand, and a lot of other things in Econ 101 don’t actually hold up in real life in various circumstances. It’s valuable to have empirical, statistically significant studies to back up (or refute) our assumptions. Without them we can only make logical connections and assumptions, which, however likely they may be, could still be entirely mistaken.

    2. Butch: Yes, although transportation planning often treats demand as a constant (“40,000 cars a day! Where will they go?”), rather than a function of price, travel time, and other variables. Supply is likewise often treated as a constant (or worse — see the well known critiques of the ITE parking generation manual.

      Shane: Is there some specific thing about supply and demand that you’re thinking of that “doesn’t hold up in real life”? Supply functions can have their quirks and kinks, sure, but it’s the rare good for which demand doesn’t increase as price falls. (This is often easiest to visualize in the negative: all other things being equal, nobody rides the bus more when fares go up; nobody drives more when gas gets more expensive.) Same for supply; producers produce more when consumers are willing to pay more. U.S. oil production is up, likely because the oil that’s left isn’t worth the effort to pump at $20/bbl but is well worth pumping out at $100.

      1. some specific thing about supply and demand that you’re thinking of that “doesn’t hold up in real life”?

        The supply and demand curves always hold up in real life. But you have no way to know what they will look like without plotting real life date. Using them to predict points along the curve where you have data should be accurate. Predictions out at the end of a curve that don’t actually exist are just a guess. The tool is most useful when there are easily substituted alternatives. A 15 minute drive vs a 30 minute bus trip might be reasonable. A 60-90 minute trip by transit not so much.

  8. Let me see if I have this right. Cars bad. Parking spaces make people drive. Build building with no parking. People won’t drive. And that’s a good thing.

    This logic made me wonder what kind of utopian counties had the least amount of evil, earth-destroying cars. Here’s the list. It seems like the countries with the most number of cars per capita are wealthy, first world countries, and then as you go down the list to the countries with the fewest cars per capita, you get into poorer and poorer third world counties.

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