While some states started out in this manner (the federal government allowed each to choose), some states have changed after the fact, forcing confused motorists to adapt and many travellers to get lost. While it seems backward to many, especially since the U.S. is officially (but not yet in practice) metric, supporters claim that it is better suited for long-distance travelers who can determine the distance to their destination (but only within the same state), or their location in case of an emergency.
Detractors point out that it is better to "leave well enough alone" and keep the original system, and that it works strongly against metrication and is almost useless for visitors and tourists from other countries. Unfamiliar motorists often get off at the wrong exit (i.e old exit 5 versus new exit 5) or may think they have missed one, and it costs millions of dollars to change every sign in a state. It also places a burden on businesses which must pay to reprint brochures, especially if a state fails to provide an overlap or grace period.