Billboard regulations are controlled on a local level, by states and various municipalities. The 1965 Highway Beautification Act specified some vague sign restrictions within 660 feet of a highway. However, the zoning regulations of a given location specify the actual requirements of billboards. Hence, there are no universal billboard requirements. Instead, billboards are often regulated based on their size, content and location.

Billboard Size

The zoning ordinances of an area often specify a maximum billboard size. Along most American highways, the average billboard size is 14 feet by 48 feet. Certain areas, however, regulate this size with slightly more specificity. For example, a 1998 ordinance in Springdale, Arkansas, specified a maximum area of 600 square feet. This regulation, like many other similar local regulations, further restricts the loose standards established by the Highway Beautification Act.

Billboard Content

Billboard content is the least-restricted aspect of outdoor billboards. A restriction of billboard content could potentially violate constitutional rights of free speech. Nevertheless, the content and display of billboards is regulated when factors such as public safety are potentially put at risk. This is especially the case with electric billboards along highways. While there may not be a correlation between billboards and automobile accidents, precaution is still exercised. A 2007 memorandum from the Federal Highway Association found that the acceptable durations for any one advertisement on an electric billboard typically range from four to 10 seconds.

Billboard Location and Density

The Highway Beautification Act established regulations for areas within 660 feet of a highway; areas outside of this are regulated by state and local ordinances. Many states and municipalities have further delimited the federal restrictions on billboard location. In fact, the states of Alaska, Hawaii, Maine and Vermont have banned billboards entirely. Other states have placed restrictions on the possible locations of billboards, restricting them to commercial areas and highways only.