Why has so much of the US highway system been decommisioned?
The Interstate system has been deemed adequate to handle the navigation task the US routes used to provide in many areas. Many state legislatures have adjusted their numbering systems over the years to make bookkeeping easier, and eliminated US routes or portions of them in the process. Since 1956, when the Interstate program was implemented in full, the mileage of the US system has decreased from 162,358 miles to 150,934 miles in 2004, or a net loss of 7%. Sep 26, 2004 7.4.1 Q: What happened to US 66? A: Navigation between Chicago and L.A. now requires following multiple Interstate numbers, but this was not regarded as a problem by the states along old 66, since the route is diagonal. In 1974, California decommissioned its portion of US 66. Illinois decommissioned its portion of US 66 more slowly, pulling it further away from Chicago throughout the 1970’s. The remaining portion from Missouri to Arizona was decomissioned by AASHTO on June 27, 1985. Most states on its former routing sti
