Unfortunately, while freeways did provide vehicular access to downtown, they also disrupted the existing urban grid and street system. Freeways severed local commercial activity from customers, and many once vibrant streets now stand with shuttered businesses and negligible street activity. -Mayor’s Innovation Project
It is conventional wisdom that motorways or other high capacity, limited access roads have no place in productive urban environments. Increasingly, cities across the globe are pursuing projects which attempt to mitigate the problems and re-insert a transport structure that supports local accessibility and high value land use outcomes. In addition to the famous tear out projects in Portland (above), San Francisco and Cheonggyecheon, there are also dozens of other cities that are pursuing flyover teardowns, motorway caps, freeways-to-boulevard solutions, and in cases total removals.
A recent publication by the Mayor’s Innovation Project, Rethinking the Urban Freeway (PDF) gives a nice synopsis of the rationale behind motorway removals including the opportunity costs of motorways which “occupy valuable land without paying taxes; reduce the value of nearby properties; and reduce quality of life in nearby neighbourhoods.”
Matt’s recent post Guess where this is? showed a stark depiction of our own transport legacy. Here’s another look at the area using a figure/foreground diagram showing the disruption of the urban fabric caused by both the CMJ motorway and the Dominion Rd Flyover.
Below is a look at the same area using a diagram to illustrate intersection density. Intersection density is a useful tool to quantify the viability and walkability of a neighbourhood. In Julie Campoli’s new book Made for Walking she uses the same technique to demonstrate that all walkable and successful neighbourhoods have a high concentration of intersections that support movement choice. The drawing shows intersections in red which allow turning options (dark red showing 3 choices, light red 2), and the black dots depict places where intersections have been cauterized by motorway-type roads.
We know that land value and productivity reach extreme levels in the city centre. The CMJ and the Dominion Road Flyover have almost completely disconnected Eden Terrace from the city centre causing a radical (and unnatural) devaluation of land. So while Eden Terrace, Grafton and Freemans Bay are ‘close’ to the city, the urban transport structure defeats the advantages of proximity. The relationship between urban proximity and land value is still based on an urban structure of ‘cityness’ which is largely influenced by walkability and accessibility to local places and services.
Here’s a look at the disurban environment of Eden Terrace. Not only is the area now disconnected from the city and its associated value but the resulting road structure tends to concentrate through traffic further isolating the remaining bits into a sort of archipelago.
Finally, here’s a recent video describing the progress of some tear out projects in America.