Bad Engineering Leads to Excessive Roads

Eric Jaffe, writing for CityLabs: 

Alan Parker,

Alan Parker,

Some of the most trusted planning tools used to manage vehicular traffic have shown themselves to be pretty harmful to city life in certain ways. A metric known as Level of Service, which aims to minimize automobile delay at an intersection, can act as a huge obstacle to public transportation projects. A design book calling for 12-foot lanes, an engineering staple across the country, can speed up car flows and endanger public safety as a result.

It might be time to add one more established tool to the questionable list: the Trip Generation Manual from the Institute for Transportation Engineers, a common guide that tells traffic planners how many car trips will be generated by a new commercial or residential development project.

In a dark place we find ourselves, and a little more knowledge with a little less dependence on assumptions lights our way.