The case of the $400 million bike lane

By Felix Salmon
March 26, 2012

Everybody’s favorite transportation geek, Charles Komanoff, has a fascinating new paper out on the economics of New York’s new Tappan Zee Bridge. The old bridge is decrepit, and needs to be replaced — everybody agrees on that. And the replacement is now in the works, at a cost of $5.2 billion. But does it need to cost that much? Komanoff makes a strong case that it doesn’t.

I won’t try to summarize Komanoff’s paper here. Instead, I’ll just point to one fact which is buried there. The new bridge comes with a combined bike/pedestrian lane, 12 feet wide. And the cost of building that lane — the amount that the cost of the bridge would decrease if you simply built it without that lane — is an astonishing $400 million.

To put that number in perspective, Komanoff tells me it would cost roughly $40 million, in the same 2015 dollars, to build two bike/pedestrian lanes on the Verrazano Narrows bridge — lanes which would get vastly more traffic than the one lane on the new Tappan Zee.

As for the cost of the first three years of New York City’s ambitious bike program under transportation commissioner Janette Sadik-Khan, that was just $8.8 million, 80% of which was paid by the federal government.

In other words, for the $400 million which governor Andrew Cuomo is planning to spend on a white-elephant bike lane almost nobody is going to use, you could utterly transform the bicycling infrastructure for millions of New Yorkers in all five boroughs.

Oh, and I almost forgot — it looks as if the old Tappan Zee bridge is going to be converted into a bike/pedestrian walkway anyway, making such a facility on the new bridge even more superfluous.

But this is how big projects always work: it’s weirdly easier to raise billions for something huge than it is to add millions to an annual budget somewhere. “Gridlock” Sam Schwartz, for instance, in his clever new congestion-pricing plan, is proposing three new massive bike/pedestrian bridges: one from Jersey City and Hoboken, in New Jersey, would span the Hudson River and land just north of Chelsea Piers. A second would go from Long Island City and Hunter’s Point, in Queens, and would cross the East River to midtown Manhattan. And the third, and most ambitious, would start in Red Hook, in Brooklyn, head over to Governor’s Island, and then continue on to the Financial District.

These are utterly wonderful ideas. If beautiful new pedestrian bridges can be built by Santiago Calatrava in Venice or by Norman Foster in London, there’s no reason New York can’t follow suit. Still, it’s a bit depressing that we don’t seem to have the mechanisms to take the billions available for vanity projects, and use some small fraction of that money for things which would make a huge difference to the daily lives of millions of New Yorkers.

This phenomenon isn’t confined to government, of course: anybody working in a big corporation has seen some huge acquisition made, using money which was never available for smaller projects from existing teams which had much clearer benefits. And there are hundreds of museums around the world which never have money for important things like conservation, but which somehow manage to find enormous sums for glossy new starchitectural projects. Basically, people want to be able to see where their money is going, in the form of something large and grand and headline-grabbing. Even if there are much more sensible uses for it elsewhere.


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I like the idea, but not on economic grounds.

Posted by Sechel | Report as abusive

This is hardly an apples to apples comparison. Verrazano Narrows bridge has already been built with the width of the bike lanes in mind. Bike lanes just need to be finished and opened to pedestrians & cyclists. $400 mil for the bike lanes on the Tappan Zee bridge is the cost to build the bridge 14 feet wider to make room for bikes.

Besides, $400 mil seems to be a considerable overestimate. Scaling exponent of 0.9 is unreasonably high, and $5.2 billion price tag almost certainly includes significant spending on non-bridge projects (such as rerouting traffic lanes from the old bridge to the new bridge).

Keeping the old bridge as a pedestrian bridge is not a certainty, there are significant renovation and maintenance costs associated with this option.

Posted by Nameless | Report as abusive

@Nameless: The Verrazano wasn’t built with room for bike and ped lanes. The 1997 study by the original builders, to which I contributed, assumed the new lanes would have to be cantilevered off the existing span. But you’re right that $400 million is too high for the Tappan Zee bike-ped lane; I mis-calculated late last night. The saving from ditching that lane is $360 million. That’s with the 0.9 scaling exponent. It’s $280 million if you take the exponent down to 0.7, but note that the bike-ped lane would require on-off ramping just like the motorized traffic lanes. Even with my error corrected, there’s still an order-of-magnitude difference between the costs of the respective bike paths.

Posted by Komanoff | Report as abusive

Yeah things like this happen all the time. Major IT emergency “spare no expense”, asking for $800 to avert major IT emergency “do we really need that?”.

Posted by QCIC | Report as abusive

As weird as as it seems, the oil industry might have a solution for this kind of craziness. When you are evaluating different projects, you might do cash flow analyses that cough up net present value (NPV) or internal rate of return (IRR). But what do you do in a capital constrained environment when you have many possible projects? This is a situation that oil and gas companies face frequently. They want a way to rank the projects to get the best possible financial results, regardless of the size of the projects involved (several small, high-profit projects may be better than one large low-profit project). NPV and IRR are not enough, so the oil industry uses a ratio called the “present value index.” Simply put, it’s NPV divided by capex plus 1. If PVI is over 1, that means it has a positive NPV. What this measures is capital efficiency–how much bang are you getting for each dollar of capital invested. I realize that bike paths and roads are not meant to be capital generating projects. Nonetheless, I think PVI could be adjusted to create a more-or-less objective way of choosing such projects. The psychological pleasure that big capital projects give to managers would be mitigated if there were a PVI-based algorithm for choosing projects. (The problem with this approach is that the free-cash-flow models used to calculate PVI can certainly be tweaked to get a better PVI. You would probably want these models to be generated by outside analysts.)

Posted by RobertWBoyd | Report as abusive

The bike lanes cost about 7% of the project. Sounds fair. But if the conversation is how to better spend money, the $5B cost to build the bridge might find some better use someplace else too. So not sure why you apply “better use” logic only to the bike lane. Why not apply it to the whole project. But that’s silly isn’t? You need a bridge. So while you’re doing it, you might as well do a bike lane too while you’re at it. After all, it’s only about 7% of the total costs. The only point that matters is if the old bridge is going to be re-purposed and include a bike use, or is it going to be torn down? And that seems like an unsettled question.

Posted by AlsatianND | Report as abusive

I thought the bike/ped lane was a placeholder for a future mass transit (BRT or LR) lane over the bridge, which had been pitched from the project a few months ago. So, it’s basically reserved lane space that would be applied towards the future cost of a transit lane. This makes it seem more sensible to include the space. And there’s certainly a possibility of people using the bike lane. Witness bicycle traffic over the GWB on the weekends.

Posted by aschildg | Report as abusive

Hey Felix, Remember when I recommended you get a unicycle? Check out Marginal Revolution.

Posted by DonthelibertDem | Report as abusive

“The 1997 study by the original builders, to which I contributed, assumed the new lanes would have to be cantilevered off the existing span. ”

I find this very hard to believe. For one, this is a difficult project and $40 million is relative peanuts for such an undertaking.

More importantly, if you can cantilever new bike lanes off 1-mile-long Verrazzano Narrows bridge, it follows that you can build the 2.5-mile-long Tappan Zee bridge without bike lanes, then use the same technique to add bike lanes for $100 millions, or 4 times cheaper than to build the bridge with bike lanes in the first place. This is almost certainly wrong: building the whole thing at once has to be cheaper.

Something does not compute here.

Posted by Nameless | Report as abusive

@Nameless: I think you’re on to something. And I don’t think it’s that the 1997 Verrazano study was botched. Maybe the Tappan Zee bike lane does *not* have to be built to the same loadings and other specs as the other 14 lanes, which might save a good deal of money.

Posted by Komanoff | Report as abusive

Is there any documentation online that explains how the $5.2 billion figure was derived?

Posted by Nameless | Report as abusive

What the lane looks like is only half the story?

Whether car drivers drive like steroid-charged idiots,
and whether bikers cycle like methamphetamine-charged teenagers and terrorize pedestrians — those are common realities why responsible cyclists avoid certain streets in cities.

I know a bike lane which abruptly ends half a block before a busy intersection, and where the pedestrian sidewalks narrow to half its size. The result: cyclists go up the sidewalk and literally terrorize pedestrians,
and the police turn a blind eye. As a result, some residents of that block have to resort to driving, instead of walking, even for just a few short blocks, to avoid getting run over by bikes! Now tell me, does that save gasoline, or the environment. Worse, how many more anxiety stricken residents have to talk to their doctors for medications or lack of exercise because they don’t feel safe enough to walk to the park!

Posted by Janeallen | Report as abusive