Question 1

● Is there any effect of cyling infrastructure in bicycling safety? – Vehicular cyling says no

– Macro-evidence from countries is quite good (Netherlands, Denmark...)

– Meso-evidence from cities is not so good (Example: Pasanen report)

– Micro-evidence from particular infrastructure ¿?¿

Question 2

If infrastructure creates safety

● Is it an additive linear effect?

or

● Is it a non-linear “quantum” effect

Question 3 (safety in numbers)

● Are the streets safer because there are many cyclists?

or

● There are many cyclists because the streets are safer?

Seville as case study

Daily trips

Length of bikeways

Methodology● Multi-linear regression analysis:

RISK = ao + a1X1 + a2X2 + ...

● Variables– RISK: Total number of accidents involving bicyclists

and motor vehicles each year

– KM: Total length of bikeways in km

– TRIPS: Million of bicycle trips per year

– JUMP:● = 0 before 2007● = 1 after 2006

Data

(*) Estimated assuming the number of trips is constant

Numerical results 2006-2013

Graphical results 2006-2013

Numerical results 2000-2013

Graphical results 2000-2013

Some considerations

● The variable JUMP is the best explanatory variable.● The variable TRIPS is the worse one.● The best model is RISK-KM+JUMP, with JUMP

significant to a 90%.

● We interpret these results as suggesting that “networking” the bikeways is important by itself, and that there is not a big causality between TRIPS and RISK

Networking

Safety in numbers?

Jacobsen (2003)!!!

; a0

CONCLUSIONS● There is a clear correlation between infrastructure and

cycling safety.● Networking seems to play an important discontinuous role

in this correlation.● Explains why macro- and micr-analysis gives different

results?● Jacobsen's safety in numbers theory is quantitatively

confirmed. ● How causality goes: From infrastructure to safety and from

safety to number of cyclists or vice-versa?