Some of my fellow advocates of cycling infrastructure are so confident in their product that they are unafraid to display it under the slogan “build it, and they will come”, a phrase which cannot help but conjure the image of Kevin Costner hallucinating in an Iowa cornfield.

While there is no doubt that the newly installed cycle tracks in central London have contributed to the growth of cycling there: just as roads and free parking encourage people to drive, safe pleasant places to cycle do encourage people to cycle. But we have a really silly situation now in greater London where some prominent and effective advocates of cycling are adamant that cycling infrastructure is the thing, and that a big and sustained rise in cycling can be achieved without actively discouraging the use of cars. They have as a foil a small number of politicians who advocate for bikes and against cars, but who maintain that cycle tracks don’t work in big cities, and can only be installed at the expense of bus service and pedestrian safety.

I don’t have time at the moment to name the proponents of these postitions, or to go into the variant of the just-build-it position which leads some cycle infrastructure advocates to see things as a choice between space for cycles and space for buses (rather than cycles vs cars). Nor do I have the time to explore whether these differences between advocates are rooted in different end goals, or different strategies with the same end in mind. I’ll just address the question of what is known to increase cycling as a share of transport within cities.

The Netherlands is often held up as the prime example of succesful cycle policy: since the 1970s, cycling has risen in most Dutch cities. But what can we learn from that? Dutch cities have built lots of cycle tracks, and have also restricted the supply of parking and limited where drivers can go. Also, the Netherlands is different from the UK in many ways – the legal liability of motorists in the case of road accidents with vulnerable users, the pattern of public transport, the size of cities, the country’s topography and culture, and so on: how can you know that it isn’t broad differences between the UK and the Netherlands that have made the difference for cycling, not the policies of particular city governments?

The best way to answer these questions is to compare cities within the Netherlands. Dutch cities may all look like good places to cycle compared with almost any UK city, but there are big differences between them. What causes those differences? Since they’re all in the Netherlands, questions law and national culture don’t cloud the picture; variables like topography and city size can be accounted for directly, since these do differ between cities in Netherlands.

When researchers in Dutch universities have used this approach, they have found that both cycle infrastructure and discouraging use of cars are important factors in the growth of cycling share.

Comparing 103 Dutch cities, Rietveld and Daniel (2004) found that both better infrastructure, and the higher prices for parking cars, encourage cycling; they estimate that a rise in the price of parking by 0.14 Euros per hour increases cycling share by 5 percentage points. Given the difference between the average price of parking in their dataset (0.17 Euros per hour) and the maximum (1.23, for Amsterdam), this implies that raising a city’s parking tariffs from the national average to the Amsterdam rate would increase the city’s cycling share by a huge 30 percentage points – almost doubling it. That’s just the estimate from one study, so it needs to be taken with a grain of salt, but if it’s anything near correct the effect of pricing parking can be huge.

A more recent Dutch study, by Harms, Bertolini and te Brömmelstroet (2016), reinforces this view. It considers only 22 Dutch cites, but includes information on changes in each of them between 2000 and 2013. Unlike Rietveld and Daniel, the new study doesn’t produce quantitative estimates, just rough classifications of what policies work under what circumstances; the lack of quantitative estimates is a limitation, but their method allows them to consider combinations of factors in a way that Rietveld and Daniel could not. Harms et al find that in cities with low cycling shares (that’s low for the Netherlands, which is still high for the rest of us), the cycling share rises in response to a combination of infrastructure improvements and increased cost of parking. That is to say, the carrot (making it easier for cyclists) and the stick (making it more costly to drive) are complementary, each reinforcing the other, so that the two add up to more than the sum of the parts.

Finally, the book Cycling Cities: the European Experience (Oldenziel et al, 2016) compares 14 European cities, five of which are in the Netherlands. It’s a beautiful book, coffee-table ready, with lots of historical photos. Rather than the statistical comparison of cities used in the other two studies, this book provides case histories. If you read the case histories of the Dutch cities in particular, you will see exactly the interaction between carrots for cyclists and sticks for drivers evident in the statistical results of the other two studies.

Build it and they will come? Maybe they will. But basing cycling policy only on the carrot of good cycle tracks would be to ignore the history of those cities that have made cycling work: they have restricted or taxed parking, and restricted driving; some are now venturing into road pricing, of which London’s congestion charge is a crude early example.

(One thing to be careful of in reading the Oldenziel book is the graphs provided in each chapter on how the city’s cycling share has changed over the years: the rise in cycling since the 1970s always looks modest, even in the big success stories like Amsterdam, Utrecht and Copenhagen. As explained by Oldenziel and de la Bruhèze in their chapter on Amsterdam, the figures used assume one mode of transport per trip, and so do not capture the big shift to using bikes, rather than buses, to get to the train. For this reason, city planners didn’t understand what was happening – their figures showed a small rise in cycling, but train stations were flooded with too many bicycles and no place to put them. So, when reading the graphs in this book, don’t make the same mistake the planners did.)

References:

Harms, Lucas, Luca Bertolini, and Marco Te Brömmelstroet. 2016. “Performance of Municipal Cycling Policies in Medium-Sized Cities in the Netherlands since 2000.” Transport Reviews 36(1):134-62.

Oldenziel, Ruth, Martin Emanuel, Adri Albert de la Bruhèze, and Frank Veraart (Eds.). 2016. Cycling Cities: The European Experience. Einhoven: Foundation for the History of Technology.

Rietveld, Piet, and Vanessa Daniel. 2004. “Determinants of bicycle use: do municipal policies matter?” Transportation Research Part A: Policy and Practice 38(7):531-50.