Melissa Bruntlett & Chris Bruntlett wrote:

The spatial demands of a car-centric city were glaringly irreconcilable with Delft’s small, compact nature, so Volmuller’s top-down, wholistic plan was embraced as a substitute. Critically, it dealt with the management of car traffic, public transport, and cycling as separate—but interconnected—mobility networks.

Recognizing that the most effective way to control a hazard is to physically eliminate it, this policy—and subsequent circulation plans implemented on a neighborhood-by-neighborhood basis—purposely prevented drivers from cutting through living areas by pushing them to an outer ring road the moment they left their front door. Not only did removing these sluiproutes (sneaky routes) create streets more welcoming for people of all ages to walk and cycle, but it also made those more desirable modes more direct and convenient. This was accomplished through the concept of “filtered permeability,” which prevented through traffic on most streets, while people on foot and bike were permitted to trickle through (and even travel the wrong way on one-way streets). As Dutch planners have discovered over the years, the most important part of an effective walking and cycling plan is the car plan. But this car management plan must be implemented in parallel with a viable alternative to driving short distances—in this case a dense, well-connected cycling network.