The New York Times has an interesting article on a public parks created in the heart of the city of Madrid, Spain when the government decided to bury the roads in tunnels. The article is in the Art & Design section of the Times, but another article could have, perhaps should have, been written on the implications for infrastructure design, construction, and funding. Notably, the title of the article is "Park Blooms Where Highways Did," implying that the roads were torn down and taken out. The author notes the miles of new subways created, but barely even mentions the fact that the real innovative part of this project was making the decision to bury the roads, not tear them out. This was a replacement project, not a tear down.
The article also notes that the city spent nearly $5 billion on the project, although it's unclear how much was spent on tunneling the roads and how much was spent on the new rail transit lines.
This isn't the first time tunneling has been considered as a solution to urban congestion and travel problems. Sydney, Austrailia and Paris have used tunneling to preserve urban neighborhoods and historic structures, for example. What is extraordinary is the extent Madrid went to move the expressways into tunnels. Tunnels are much more expensive than surface streets. How can the costs be justified? Without tolls or road pricing, an effective way to objectively value benefits and costs is hard to come by.
Moreover, while the New York Times emphasizes the public park aspects of the project, completely missing from the article is any speculation or analysis of the potential commercial value of the land. Putting roads underground creates entirely new options for building high-value urban neighborhoods. Costs could be justified based on benefits generated through land value capture.
Right now, however, the Madrid case seems like a missed opportunity to use market-based approaches to developing a sustainable funding source for infrastructure development.