paris: did rail worsen freeway congestion?

Can transit projects be judged based on the "welfare" of various user groups?

IMG_0771 If you know how to equate the "welfare" of a transit rider with the "welfare" of a motorist, and are not concerned with any other forms of welfare, you can do a calculation that appears to say whether a transit project was a good idea.  

From a new paper in World Transit Research by Rémy Prud'homme. 

In Paris, an old bus line on the Maréchaux Boulevards has been replaced by a modern tramway [the T3, opened in December 2006]. Simultaneously, the road-space has been narrowed by about a third. A survey of 1000 users of the tramway shows that the tramway hardly generated any shift from private cars towards public transit mode. However, it did generate important intra-mode [shifts]: from bus and subway towards tramway, and from Maréchaux boulevards towards the Périphérique (the Paris ring road) for cars. 

… The welfare gains made by public transport users are more than compensated by the time losses of the motorists, and in particular, by the additional cost of road congestion on the Périphérique. The same conclusion applies with regard to CO2 emissions: the reductions caused by the replacement of buses and the elimination of a few cars trips are less important than the increased pollution caused by the lengthening of the automobile trips and increased congestion on the ring road. Even if one ignores the initial investment of 350 M€, the social impact of the project, as measured by its net present value is negative. This is especially true for suburbanites. The inhabitants (and electors) of Paris pocket the main part of the benefits while supporting a fraction of the costs.

So here is our plate of facts:

  • On series of boulevards running parallel to the Périphérique, the motorway that circles Paris, traffic lanes were removed and a light rail line was added.  This was done less than five years ago.
  • The light rail line didn't attract new riders beyond those already on the bus and subway systems.
  • The closure of traffic lanes caused traffic to shift from the boulevards to the motorway, increasing congestion on the motorway, therefore affecting many motorists traveling long distances around the edges of the city. .
  • As a result, the benefits tended to fall heavily within Paris, among public transit patrons on affected boulevards, while the disbenefits fell on suburban motorists.

All that may be true.  Does this mean the rail line was a mistake?  Discuss.

26 Responses to paris: did rail worsen freeway congestion?

  1. Angus Grieve-Smith July 30, 2011 at 7:56 pm #

    It’s important to note that the authors did not measure traffic on the Périph. They just observed that average speeds on the highway declined from 45.9 km/h to 43.5 km/h, and that “many witnesses of the public hearing on the extension of the tramway to Porte de la Chapelle testified their fears to see an analogous shift increasing the congestion on Eastern Périphérique.” In other words, bullshit.
    The fact is that a large portion of the traffic on the Périph is going from one side of the city to the other. If some of the drivers on the Maréchaux transfered to the Périph, increasing congestion there, some of the drivers on the Périph would take commuter trains across town instead. Some of the drivers would find it more convenient to take the metro instead of the tramway, or to drive an alternate route that doesn´t involve the Périph, possibly one of the parallel boulevards closer to the center of the city.
    There is also no mention of the human cost of the noise, carnage and general unpleasantness of the Maréchaux before the tramway. I used to live on the Boulevard Ney, and it was not a great place to walk. This tramway has improved the quality of life of thousands of people who live along those boulevards, and this is not a ritzy section of Paris.
    If it’s at all true that the burden of this tramway has fallen disproportionately on suburbanites, the remedy is simple: more suburban tramways.
    The authors also engage in the same shell game perpetuated by the likes of Richard Brodsky here in New York: there are working-class people in the suburbs, people in the suburbs drive, and therefore this is a strike against working-class people. The fault in this logic is that the working-class suburbanites are generally not the ones driving on the Périph during rush hour. They´re on the train.
    This is a hack job. It´s an elaborate house of cards that they´ve built to try and pin something on the tramway. Pathetic.

  2. ant6n July 30, 2011 at 8:46 pm #

    Is it bad to force driving suburbanites onto a highway, rather than packing onto urban boulevards where people actually live?

  3. George Bell July 31, 2011 at 12:02 am #

    5 years is a short time in a city like paris…obviously over time density will change the facts…in most major cities it takes that long for a newby just to figure out the fair structure for the system, you can’t expect motorists who just bought a new car to sell it 5 years in…give it 30 years and you’ll probably get a bit more use out of it….the first subway in new york only went 300 feet…I mean, it didn’t really go anywhere that people wanted to go, and it only had one car, and it only had one station (you had to leave the way you came in)…good thing they didn’t listen to the crazies who said it was pointless to build a subway…

  4. Felix the Cassowary July 31, 2011 at 1:46 am #

    Um, George Bell, that “first subway in New York” with only one station where “you had to leave the way you came it”. Um. Wasn’t it utterly pointless to build it? Are you saying people would go down into the station, hop on the train, ride down 300 feet, wait for the train to turn around, a ride back 300 feet, then get off? Like some sort of amusement park ride?
    I suppose amusement is a valid point, and I imagine that this was meant to be just the first step in a longer project, but I am surprised anyone would bother opening a subway like that, instead of just waiting until they’d finished construction of at least another station.

  5. Andre L. July 31, 2011 at 2:21 am #

    I think this illustrates how trying to “force drivers out of their cars” is just an approach that doesn’t work. “Premium” tramways and similar projects usually divert transit users from other transit options.
    Cars are and must be considering as permanent ingredients of any traffic planning in a major area. As much as it is wrong to assume everyone is going to drive, it is also wrong to assume no one is going to drive.

  6. [email protected] July 31, 2011 at 4:12 am #

    Make use of the high capacity of trams. Add a congestion charge on the freeway to get people out of the car and onto tthe tram. The remaining cars flow freely, and the air will be cleaner.

  7. Jeff Wegerson July 31, 2011 at 7:10 am #

    Congestion should be kept separate from air quality issues. If all the cars were electric there would be no air quality issues but there would still be congestion issues.
    There is only one way to address congestion issues and that is to increase capacity. A tram increases capacity as would an additional lane for cars. Since an additional lane for cars cannot come from removing pedestrian and bus lanes it would need to come from removing housing and commercial space in an urban environment or green space in a non-urban one.
    Slowing cars down from 45.9 km/h to 43.5 km/h actually increased capacity on that roadway in terms of people per hour moved through it.
    The best solution for improving travel time is to change the locations of where you are coming from and where you are going to. That not only reduces travel time but it reduces capacity needs as well.

  8. Tristram July 31, 2011 at 7:48 am #

    Before the tram, there was a strong bus line. Not always on a seperate lane, but with a high ridership (arround 100 000 passengers/day) and a rather high average speed (more than 15km/h wich is quite fast for Paris). The car share of real Parisian (those 2.2million people living in 100 already very low (someting arround 20%).
    The area where the tram was built, is very residential, so people living in the suburbs have no need use for it.
    So the tram indeed didn’t change much.
    However, it was a very big and needed urban renovation. A lot of people (rather lower social classes) live arround those maréchaux, and having an urban highway under your window is not pleasant. Now it became far more livable.
    I´d say it fixes an old mistake : the maréchaux should not be used at all for car transit, as the périphérique exists (they´re only 1km appart, so saying it increses distance is only bullshit).
    So the line was no mistake, and I´m eagerly waiting the extensions.
    The main mistake of Remy Prud´homme, is to put in the same bag very local transit (bus and tram inside Paris) and broader transit (for distances over 10km made by car and heavy rail).

  9. Andre L. July 31, 2011 at 10:00 am #

    There is a flaw on this assumption: “Slowing cars down from 45.9 km/h to 43.5 km/h actually increased capacity on that roadway in terms of people per hour moved through it.
    The speed that optimized traffic on a controlled-access freeway without obstacles like blind ramps or curve radii below 200m is something on the range of 80-105 km/h, depending on composition of fleet travelling there, presence of lighting during night time etc. These are the speeds where the distance between vehicles x speed of vehicles is optimized for maximum output of vehicles/lanes. Above that range, capacity is reduced because of increases on distances between vehicles, in an automatic way (more cars = lower speed). Below that range, the amount of time each vehicle takes to clear a sector outstrips any gain coming from reduced distance between cars.
    To use slower transit (in whatever form) as a proxy to compel people to live close to work is, in my opinion, unacceptable interference of government on the real estate market, a negative form of social engineering. It reminds me of some Singaporean high officials who started a “campaign” for lower-income people to “put up” with lower wages to work close to home, so that they wouldn’t need to stress the system on peak times.

  10. TransitPlannerMunich July 31, 2011 at 12:13 pm #

    Facts first:
    – the 320 million costs went largely into an improvement of the area, a complete urban redesign including also 1000 trees planted
    – the ridership increased (compared to the bus lines) dramatically.
    – the bus lines before the tram had daily 60,000 passengers, not 100,000 as stated in one of the comments before
    – the ridership rose from 60,000 (bus line) to over 110,000 daily or 30 million per year, almost double the ridership. And that on a line with less than 8 km!
    Among us there may be some transit and traffic planning professionals. So am I the only one here recognizing what a tremendous amount of passengers that is?
    To have such an amount of people transported by car you need 2-3 lanes in each direction, 4 to 6 in total.
    Even for a heavy rail system that would be an impressive number of passengers.
    And even if a part of those riders switched from the metro it would be a welcome relief to the overcrowded metro and would be filled up there soon by other riders.
    The theory that such a system would not be beneficial but even a problem is an idea that is not even worth to be discussed further.

  11. Dist July 31, 2011 at 1:22 pm #

    Nice to stumble on this piece right after reading Alon Levy’s article named “High Costs Should not be an Excuse to Downgrade Projects”. The last point being, that if people behave as if there is no money for good projects they will end up with bad projects.
    And I think that to some extent this is here the case. The T1, T2 and T3 ring was imagined after the project of a new orbital subway line passing through the inner suburbs was abandoned.
    At the time Paris was involved in a very ambitious plan of tunneling two new public transit infrastructure through the core city: the M14 and the Eastern stretch of the RER E. The plan was ambitious and expensive, at first the idea was too build only one of those two projects but both were given the green light for simultaneous construction.
    Those two projects where finished to see the reins of Paris transportation given to the Regional and local authorities. The transfer was not easy and was completed in 2006.
    At that time the more ambitious projects had been shelved for less expensive, easier to do projects, like the ring of tram lines.
    And this is where Rémy Prud’homme is misleading and also making a mistake in his analysis. He is comparing the T3 (a very local line) to a regional infrastructure (the Boulevard Périphérique). They have nothing in common and I don’t think the T3 was ever thought and designed to alleviate car load on a motorway ring.
    The T3 is only a secondary surface line, not a main (subterranean) line. And Rémy Prud’homme analysis would have been interesting if the original project (meaning: a new orbital subway line through the suburbs) had been constructed (which should be happening in the not so distant future with the “Grand Paris Express” plan).
    After all, the T3 is only running through a frontier zone that has almost no important destinations to service. The only regional flux generators are located between Porte de Versailles and the Seine. Where the T3 is now connected to the T2 to la Défense. Something that might have changed a bit the commuter flux involved.
    The real demand for rapid transit is in the suburbs, right on the other side of the Périph and the broader range movements are still serves by the M6.
    Last but not least, there was almost not much mobility gains to hope here (the bus already had their own righ of way), only a capacity increase and a pacified urban area with less bus and less traffic.
    As noted by Tristam the line is not a mistake but also not the answer to Paris’ real transit problems.

  12. d.p. July 31, 2011 at 4:36 pm #

    FYI, Felix the Cassowary,
    George Bell was clearly referring to this: — a demonstration project that never took off commercially. George’s point is that it helped put into New Yorkers’ minds the idea of fast, underground rail, an idea intrinsic to the way the city grew up in the 20th century and one of its defining features today.
    I’m not sure it’s an entirely relevant example, but that is the point he was trying to make.

  13. Ben Smith July 31, 2011 at 8:37 pm #

    Even though the WTR doesn’t seem like a wolf in sheep clothing, I do question the motives behind this report. They claim to sample 1000 riders and which most were not converted from driving, yet depending on whose numbers to believe the actual ridership grew from 10%-80%. Surely that is not all from new residents to the area…
    Secondly, Paris is a city with a fantastic transit system. I’d assume that most local trips along this corridor were already taken by transit, while those requiring distance took the highway. Depending on the before and after travel times, I could see many people who drive this stretch switch to the tramway rather than detour to the highway for a short stretch. Using Google traffic data, the south stretch of the highway does appear to be the most congested part, including during midday, though. However, I cannot comment what this stretch was like before the tramway was built.
    For the record, I do not condone careless removal of traffic lanes for transit. However, I do support and encourage such moves where it can be done with minimal impact on other modes of transportation and/or it serves a greater good.

  14. Ben Smith July 31, 2011 at 8:38 pm #

    …(Forgot to add) This seems like one of those situations.

  15. Alon Levy July 31, 2011 at 9:28 pm #

    Can someone here who’s read the paper (Angus?) send me the full text? Apparently I don’t have academic access to it.

  16. Alan Howes August 1, 2011 at 3:03 am #

    Can someone who knows the patch tell us what the objectives of the T3 project were? It seems at first glance strange that there was no private-to-public modal shift – but I suppose if most people were already travelling by transit, that’s not too surprising. In which case the T3 can be seen as a straightforward improvement in the transit system to benefit existing users (have speeds gone up?). And the evidence for adverse impacts on motorists looks unconvincing.
    So – not a mistake then.
    Incidentally, i am afraid that Dubai has a rather expensive monorail (at The Jumeirah Palm) that functions just like that “first NY subway” did – now that WAS a mistake!

  17. Zoltán August 1, 2011 at 3:38 am #

    @Andre L
    “trying to “force drivers out of their cars” is just an approach that doesn’t work. “Premium” tramways and similar projects usually divert transit users from other transit options…”
    I don’t think that this proves anything of the sort. People certainly reconsidered their car trips on Maréchaux, and the presence of the Périphérique nearby is likely to have defined for many just what the rational choice was. Without the Périphérique, transit might have been the most rational choice for more people.
    Besides, to to “force drivers out of their cars” is not the only, or even most important, aim of good transit. Public transport users being diverted from modes that didn’t serve their needs as well to one that served their needs better, then a lot of people have benefited from improved mobility, and that’s a good thing.
    “Cars are and must be considering as permanent ingredients of any traffic planning in a major area.”
    Cars are with us for the near future, that’s for sure. But what this paper has shown us is that cars in cities, like some persistent weed, will appear wherever you give them the necessary space to do so. That suggests that a valid course of action is to not consider cars at all – simply give transit the exclusive space it needs to operate reliably, and pedestrians the space required to make for a pleasant city environment, and let cars occupy what’s left over.
    Like those now using the périphérique, people determined to reach their destination by car will find a way to do so, while everyone will have the choice of good transit when they want it.

  18. Jeff Wegerson August 1, 2011 at 6:49 am #

    @Andre L.
    Thanks for the math on speed vs. capacity. I assume your numbers are right unless I hear differently, of course.
    As for:
    …unacceptable interference of government on the real estate market, a negative form of social engineering.
    I could just as easily claim that providing easy transportation options covering long distances is unacceptable government favoritism to an already overly privileged real estate market. Those people choosing to live great distances between the places they choose to travel should manage on their own without a nanny state taking care of them when they cry about travel times. 😉

  19. Alon Levy August 2, 2011 at 2:24 pm #

    The answer to the question in the blog post’s title is “We don’t know.” The study’s even worse than Angus says it is: it does brandish total traffic volume figures for roads other than the Peripherique, and uses different years for comparison. (And it’s even worse than I’m portraying it here; it’s full of other questionable or outright wrong assumptions, e.g. on costs. Head over to my place for a fuller takedown.)

  20. August 2, 2011 at 10:34 pm #

    Like others commentators, I have to rely on the summary of the article, but in what is called the “plate of facts” by Jarret, I see fallacies.
    “Simultaneously, the road-space has been narrowed by about a third”
    That is wrong, the tram line has replaced bus only lanes (put in place in 2000), so it has been no reduction in space for general traffic since the tram at opened.
    The inhabitants (and electors) of Paris pocket the main part of the benefits while supporting a fraction of the costs.
    According the own finding of one of the author, 50% of people using the tram come from the suburbs: not bad for an 8km line not going outside Paris.
    As mentioned, by previous commentator, this line has no regional pretension: 17% of ridership come from people not moving before: is the “mobility increase” of those people not a net economic/social benefit?
    If not, what is wrong then to reduce the one of the motorist?
    But you will guess in the proposition of the author, a political taint…
    Which was more affirmed in 2008, or before the tram (but same city council), when the same authors had another scapegoat for the slowing traffic in Paris.
    So as other commentators, I doubt the seriousness of the mentioned paper, but will not comment further haven’t got to read the paper in full.

  21. voony August 2, 2011 at 11:48 pm #

    probably the scapegoat link came wrong in the comment above. It should be like

  22. CroMagnon August 3, 2011 at 12:38 pm #

    “The theory that such a system would not be beneficial but even a problem is an idea that is not even worth to be discussed further.”
    This is the kind of religious type, censorship thinking that pervades the planning community. That one can’t even ask a question, it’s assume a priori that all transit is good and is an improvement. What is the problem at analyzing a project mathematically and determining if it makes sense insofar as improving mobility?
    If the authors analysis is accurate I’d say it’s a bad project. However, the above commentary suggests otherwise. Either way, scenarios exist where new fixed guideway transit would reduce overall mobility.
    And cars are not necessarily like weeds. Weak economic regions don’t see cars filling up new roads. And frankly, sometimes people will simply not make a trip and engage in whatever activity because of traffic. Some trips simply won’t reroute. They will be crushed into oblivion. Demand destruction is real, it’s just harder to see. Better for the environment, probably. But lets not kid ourselves with regard to economic output. Anything that gets 100,000 rides daily should almost by necessity be a true subway unless it has very low peak hour loading. Even still, it assumes little growth.

  23. voony August 3, 2011 at 10:39 pm #

    Cromagnon, you also seem dangerously “dogmatic” when you say:
    Anything that gets 100,000 rides daily should almost by necessity be a true subway unless it has very low peak hour loading.
    That is typically the case of the tramway T3,
    see story-telling p64 of this study showing all what is important (no need to understand french):
    ridership of the extended tramway T3 is expected to be 250,000, but no more than 3,800pphpd (RATP estimates max tramway capacity at 4,500pphpd).
    another important number is the expected journey length, 3.5km (it is actually 2.5km): it is important because it help to better estimate the real time gain for average user.
    That said, an audit by the french “Cour des comptes” show where question need to be raised for the tram.
    This one could be acclaimed as a success because it got ridership over prediction, but that means the model was also flawed, and that is a problem.
    the model shift from subway to tram has been more important that predicted (it has also been the case in London, when the bus service has been improved with the congestion charge), and that could deserve more study (may be in the geomtry scale of Jarret, it is a question of fashion but it could be also a biological factor telling us that we prefer travel in surface…and model doen’t integrate that?)
    Like in many other tram project of this kind, as the toronto St Clair Streetcar, this tram failed to deliver on average speed promise…so all economic calculation has been flawed at the advantage of the tram…
    later one, it appeared to the auditor that in fact the bus average speed could have been improved to be in the tune of the one achieved by the tram !
    The audit says another thing making the case of the study author against the commentator Angus:
    350 M€ concern the tram work, not the “urban requalification” of the street, and that is fair to separate the both, because as advocated by the author have a nice street is not a causality of tramway but just a political choice driven by opportunity.
    One will note that the audit mention a rather marginal modal shift from cars to tram, so there is no surprise here…more surprising is that this modal shift could have been somewhat 3 times more in the “subway” case (called PCF for “petite ceinture ferroviaire, an unused railtrack circling Paris and close to the boulevard where the tram has been build)… which could have freed some road space for…more car?
    PS: for the interested reader the original suty report of the tram T3 (in french) is here here, that somewhat help to put back the things in context.

  24. CroMagnon August 5, 2011 at 8:34 am #

    That’s why I was equivocating a bit. Indeed, an average trip length of 2.5 km is extremely short. Certainly, the peak hour loading would be a lower percentage of overall ridership than an arterial trunk line. Still, I stand by my concern about potential ridership growth (if it were to occur) and that economically, a true subway would probably be better. It would certainly be less susceptible to overloading and bunching and have much better reliability.

  25. Ian August 25, 2011 at 4:49 pm #

    I’m looking for someone more familiar with Paris than I am to help out with this question. The ridership for the T3 seems very high, but as voony pointed out, the average trip length is only 2.5 km. It seems like few people travel the line from end to end. With connections to 7 Metro Lines, the T2 tram line and 2 RER commuter rail lines, I would assume the T3 is used primarily as either a connection from suburb to fairly local destinations or to connect to the Metro, T2 and RER lines intersecting the T3 route. Is this assumption accurate? Thanks!

  26. Jarrett at August 26, 2011 at 9:17 am #

    Ian.  Yes I think people connect in all directions, and do shorter distributing movements on the tram.