Imagine driving across country in the 1920s. At that time, roads weren't numbered. To navigate the nation's highways, the traveler had to follow an informal system of national auto trails that had been developed by local groups. Each trail was named after the places it connected; a name of a political or military leader; local landmarks or historical figures; or a pleasant-sounding or unique name. The trails were identified by colorful bands and symbols painted or posted on telephone poles along the route. As the system of trails grew, many trails used the same roads and telephones along those routes became festooned with multiple colored bands and symbols. Because interpreting the pole decorations had become a distraction from safe driving and complaints had arisen about how routes were being designated around the country, in 1925, the federal Joint Board on Interstate Highways was convened. It developed a system for numbering U.S. highways in which north-to-south highways receive odd-numbers and west-to-east highways receive even numbers. The odd numbered highways have the lowest numbers in the eastern U.S. and the even-numbered highways have the lowest numbers in the north. The numbering system is similar for interstate highways, except that the odd-numbered highways increase from west to east and the even-numbered highways increase from south to north.