viernes, 2 de diciembre de 2016

The Pasanen Report

(Versión española aquí)

Anyone who has a friend who is in favor of the theory of "vehicular cycling" knows the Pasanen Report, either by its name "The risks of cycling", or as "the report that proves that cycle paths are more dangerous than the carriageway ". The Pasanen Report was written in 2001 by Eero Pasanen, an engineer from the Helsinki Transport Department and a black novels author. Its main thesis is that "it is safer (for cyclists) to ride along carriageway, between cars, than through ours (refers to Helsinki) bi-directional cycle paths". After complaining that "it is hard to imagine that our present two-way cycling network could be rebuilt", Pasanen adds "But in those countries and cities which are just beginning to build their cycling facilities, two-way cycle paths should be avoided in urban street networks."

It is not surprising that supporters of vehicular cycling, which state that cycle paths are more dangerous than the carriageway, and should therefore be discarded, have the Pasanen Report amongst its texts of reference.

But does this report resists a critical analysis? The bulk of his argument is summarized in the attached figure, which compares the cyclist accidents that occurred in different scenarios:

The figure compares the total length of cycling trips on different ways (in blue) with the number of accidents recorded on those ways (in yellow), all in percentages. Apparently, the image shows that the percentage of cycling accidents on the cycle paths along the streets of Helsinki is higher than their share of the total of cycling trips. From where Pasanen deduces that it is more probable to suffer an accident while circulating on a cycle path than while circulating on the carriageway. 

A first methodological criticism to the Pasanen Report and its conclusions is that it is what is referred in social sciences as a "cross-sectional study", that is, a study that compares events taking place simultanesously. However, this is not the most appropriate method for the present purpose. In fact, it can be assumed that bicycle paths were built on the most dangerous avenues, in order to reduce their danger for cyclists. So, we do not know if the supposed higher danger of bicycle paths is simply due to the higher danger of the street itself. It would have been much better to do a "longitudinal study", comparing the accident rate on a particular route before and after building the cycle path. In this way, it would be possible to know with certainty its effect on cycling accident rate, irrespective of uncontrollable factors, such as the danger of the street itself (due, for instance, to a higher or lower traffic density).

But the main criticism refers to the classification of roads and, in particular, to the distinction between "separated" and "not separated" cycle paths. If we consider all the cycle paths together, we see that the total length of the bicycle trips on them is 45 + 26 = 71%, while the total number of accidents is 56 + 8 = 64%, and the comparison is favorable. The "separated" cycle paths account for 26% of the length of the bicycle trips and only for 8% of accidents. Therefore, to "rebuild" the Helsinki cycling network, improving their safety, does not seem as difficult as Pasanen claims: It would suffice to separate the bicycle paths from the carriageway by some physical elements, such as bollards or curbs.

Eero Pasanen also worried in his report about the competition that cycling does to public transport, a competition that is also seasonal in Helsinki (there are many more cyclists in summer than in winter). It is a specific problem of cities with an extreme climate, such as Helsinki. But it has nothing to do with the thesis of the dangerousness of the cycle paths relative to the carriageway, which Pasanen wields as the core of his argument.

The Pasanen Report dates from 2001 and does not seem to have had too much influence on the city's mobility policy. Helsinki is preparing to organize the Velo-city Conference in 2019, and plans to reach 17% cycling mobility by 2025.

No hay comentarios:

Publicar un comentario