Sign bases can be made of concrete, metal (iron and aluminum), and rubber. Out of these, bases made of recycled rubber are rather popular as these are heavy and perhaps the most durable of all the sign base materials. Requiring minimum maintenance, these bases are best suited for the outdoors and offer the best resistance to strong winds.
Metal sign bases are also a popular choice, iron bases particularly, that offer benefits such as portability and great resistance to winds, bumps, and abuse. The lightweight aluminum bases are perfect when you want a quality base at an economical price.
Sign bases are commonly used where sign mounting on walls or fences is not possible, such as outdoor parking areas. Given their conspicuity, these are a recommended choice when you wish to convey important messages that people must not ignore.
Concrete sign bases are heavy and incur a high shipping cost. These don’t create a very pleasing sight and are difficult to move. Easily affected by weather, road salt, vehicular and other impacts, chemicals, etc., concrete bases demand frequent maintenance. These are the reasons why more and more people are moving towards better and more convenient and durable options, such as metal and recycled rubber sign bases.
The MUTCD requires that sign foundations, posts, and mountings be constructed to be able to hold signs in a proper and permanent position while offering reasonable resistance to wind and vandalism. While the authority doesn’t say much about sign bases specifically, it does provide some guidance about sign supports such as wood posts, U-channel steel posts, square or round tube steel posts, and I-beam steel posts. You can find information about the size, placement, and maintenance of these posts here.