Debunking Transportation Rules of Thumb
What a marvelous device are our thumbs. They are so useful that we employ them in a figure of speech: Rules of thumb. Rules of overwhelming consensus, indisputable, golden.Except when they’re not.SmartTowns.org shared a blog from economist Joe Cortright dispelling some of the rules of thumb that are gospel to highway engineers and anathema to planners creating places.Old Rules
- We should have a high “level of service” on our streets
- Wider streets are safer streets
- We should require “enough” off-street parking for every use
- We should plan for a certain number of car trips to be generated by every land use, no matter where it is.
- We should have a hierarchy of streets
- Slower is safer
- Sharing is efficient
- Our objective should be accessibility, not mobility
Cortright’s details for each rule make a compelling case.