Victor Dover and John Massengale's epic book Street Design is our most thorough explication of where we have gone wrong with our most important urban public spaces - our city streets - and how to do better. But for a clear and concise introduction to the subject, watch this five-minute video produced by Fast Company. The images are of Seoul, Korea, which in recent years replaced a congested eyesore of a downtown freeway with a spectacular linear park.

More about the freeway and linear park in a minute. Here's the video:

That is as succinct and eloquent an introduction to the subject as I have seen recently. I wish I had found the clip in time to show it to the University class I teach on sustainable communities.

Video aside, the Seoul story is a good one. As Brian Merchant reports in Treehugger, long ago Seoul's planners and engineers paved right over a polluted natural riverway and put an elevated freeway in its place. Things stayed that way for decades but, in 2003, the city tore down the old highway and brought the river - the Cheonggyecheon, really more of an urban stream - back to life. Traffic still flows on surface streets alongside the new park.

Running freeways through the hearts of cities has proven to be a mistake. They bifurcate neighborhoods and create blight. Property values plummet close to freeways. They simultaneously make city cores less attractive and suck people and investment out to the suburbs. Fortunately, there is a burgeoning trend here in the US to replace aging freeways with boulevards, which have been shown to move traffic just as well while creating rather than diminishing value.

Seoul took the concept further. In 2010, Bridgette Meinhold summarized the particulars for Inhabitat:

"What was once a dividing line between the north and south parts of the city has been recreated as an urban park that bridges the gap and brings people together. Over 75 percent of the material torn down from the old highway was reused to construct the park and rehabilitate the stream. Now fish, bird and insects have made their way back into the urban river, and the area surrounding the park is about 3.6 degrees C. cooler than other parts of the city.

"In addition to the restoration project, Seoul has also implemented transportation planning, rerouting traffic through other corridors and adding more public transportation. As a result there has been a decrease in the number of vehicles entering the city and bus and subway use has increased. Even though the city took away one of the major thoroughfares, they were able to redirect and decrease traffic through efficient planning and expanded public transportation."

Spectacular though the transformation has been, I would be remiss if I did not add that some conservationists have criticized the project. The daylighted river has not been fully restored to its natural state but, instead, is fed by heavily treated water from the larger Han River. At least one commenter has called it an "environmental disaster . . . a massive cement work and [a] death trap for fish."

Still, most observers seem to consider the project a net plus for the city, and to me what is there now is surely better than a paved-over, dead waterway with a blighted freeway on top. For more, see Lucy Wang's excellent commentary and photography on Inhabitat.

Move your cursor over the images for credit information.