Some do. Michigan has had it since 1974 [0]. Of course, it was a bit less dependent on technology when it started. [0] http://www.michigan.gov/mdot/0,1607,7-15

Some do. Michigan has had it since 1974 [0]. Of course, it was a bit less dependent on technology when it started. [0] http://www.michigan.gov/mdot/0,1607,7-151-9615_11228_11234---,00.html http://www.michigan.gov/mdot/0,1607,7-151-9615_11228_11234--...