Case Studies   Seattle: North 145th Street       In Seattle, a pilot project is currently underway using porous concrete. Many neighborhoods in Seattle don't have sidewalks. Sidewalks are often expensive to install because they require the installation of expensive drainage systems, such as storm sewers. As a result the city often cannot afford to install sidewalks in neighborhoods that need them. On N 145th St, Seattle Transportation and Seattle Public Utilities are experimenting with using porous concrete in order to avoid the prohibitive expense of installing drainage systems. This project was only just completed in January 2002, and as a result, the city has yet to determine whether the project will be effective. A technical team will monitor the pavement's ability to absorb water over time and will determine its durability.