I recently realized that more and more cities and metropolitan areas are exploring the creation of pedestrian zones. Besides the environmental factors (unclean air, noise) and the philosophical (in what kind of society do we want to live?), the simple economical aspects are for me quite large enough to go for it. Still, many cities hesitate due to expected costs, fears of negative economic effects and of a challenging implementation.
Funnily you can observe that the fear of chaos during implementation is often the most cited fear when going through any political process.
I have experienced such a transition myself in Zurich, where the Limmatquai became mostly a pedestrian zone. We had the same discussions, it will be chaotic, the roads around the city center do not have sufficient capacity, we will experience much more congestion etc. Interestingly, the opposite happened. People adjusted, adapted their paths and we have experienced almost no negative effect on traffic but many positive effects. Public transport as well as slow transport modes are faster and much more attractive in the city center while the automotive traffic flows with much less congestion around the city center. The effect on commerce is somewhat mixed. businesses that produce heavy goods had difficulties to sustain their customer base while others such as restaurants benefited heavily. It certainly supports a more expensive mix of shops, a more expensive mix of buildings which needs to be taken into consideration before planning such a measure.
I think it is interesting, that nowadays many more European cities are experimenting with pedestrian zones.
To sum it up:
+ can reduce overall traffic
+ air quality/noise
+ customers for commerce
+ real estate values
– implementation costs can be high (if infrastructure changes are involved)
– change can be perceived as a risk
In 2004, the EU even published a paper under the title “Reclaiming the City” http://ec.europa.eu/environment/pubs/pdf/streets_people.pdf discussion this topic. However, I see even more potential in growing metropolis in Asia, South America and Africa where planning of an integrated city with pedestrian zones is even a bigger challenge.