Bike lanes beget bicycles

Meta-research shows that more bike lanes generate more cyclists:

Buehler and Pucher found that the presence of off-road bike paths and on-street bike lanes were, by far, the biggest determinant of cycling rates in cities. And that’s true even after you control for a variety of other factors like how hot or cold a city is, how much rain falls, how dense the city is, how high gas prices are, the type of people that live there, or how safe it is to cycle. None of those things seem to matter quite as much. The results, the authors write, “are consistent with the hypothesis that bike lanes and bike paths encourage cycling.”
If that sounds overly obvious, the authors do note that previous research was somewhat scattered on this question. A few studies had found that more bike lanes in a city were associated with more cycling, though it was unclear which was causing which.

The tricky question here is the direction of causation, and it’s likely that causation runs both ways. To claim that bike lanes generate cycling we really need a plausible hypothesis for why that might happen. Thankfully, it’s not that hard: bike lanes lower the cost of cycling because they’re more pleasant and less dangerous. Lower prices mean increased demand for cycling.

OK, so building bike lanes makes cycling cheaper, which gets more people cycling. But that doesn’t mean they’re a good idea, unless more cycling is just inherently good. To decide whether it’s good policy to build more bike lanes we need to compare the cost of building them to the price that people are willing to pay to use them (plus any externalities). Hopefully that’s what’s being done, even though the local newspaper makes it sound as if the main issue is the strength of the cycling lobby!

Obvious perverse incentive of the week award goes to…

As rightly pointed out over at Kiwiblog, when you make something free you distort incentives around use of that good or service.

The previous Government introduced a Supergold card, offering concessions and discounts on various goods and services. In all their wisdom, they offer free off-peak travel on certain public transport. One such service was the Fullers Ferry to Waiheke Island.

It has now been reported that pensioners flocking to Waiheke Island have delivered more than $750,000 in Government subsidies to Auckland ferry operator Fullers in the first five months of free travel, with an average of 200 pensioners per day taking in the journey.

Who could possibly have foreseen that response?

Raising the drinking age: Not a lifesaver

Just saw this article courtesy of Greg Mankiw. In the article the authors talk about the impact of rising the drinking age from 18 to 21 in the US. There were two parts – a voluntary lift in some states, and later on a legislated increase for the whole country.

The key bit for me is this (highlighting by me):

The results are striking. Virtually all the life-saving impact of the MLDA21 comes from the few early-adopting states, not from the larger number that resulted from federal pressure. Further, any life-saving effect in those states that first raised the drinking age was only temporary, occurring largely in the first year or two after switching to the MLDA21.

So this isn’t saying that lifting the drinking age is necessarily a bad idea – but that it isn’t necessarily going to save lives either. In the end only the states which did it voluntarily (where it was more of a community effort) had any impact – and even that was only temporary.
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Subsidising cycling

Freakonomics reports that an Oregonian politician wants to implement bicycle licensing and registration. He says that cyclists use the roads just like cars, but they don’t have to pay a cent towards maintenance. Cyclists’ comments reveal their disgust at the idea but, as an avid cyclist myself, I must confess that I have some sympathy with the proposal. Continue Reading →