The answer to this question can be quite complicated. If you are going to do it correctly there are complex formulas that factor in car speed, number of lanes, reaction time of the driver and much, much more. For our purposes there are a few factors that you should consider and some rules of thumb to follow and your sign should be perfectly legible without worrying about the complex formulas that are out there. The most important factors that will impact your flag’s legibility to consider are: the distance from the road and lettering height, the size of the flag, and the design of your flag. Let’s tackle each of these individually. For most businesses it’s safe to assume that your roadside flag will be within 10-40 feet of vehicle passersby. Some rules of thumb suggest your lettering be 1” of height for every 10 feet. Others, recommend lettering height anywhere from 4”-10” for distances ranging from 10ft - 40ft. Thus, with flags that are presumably within 20 or 30 feet of the road if your lettering is anywhere from 3”-6” high you should be safe in terms of legibility. The next factor is the size of the flag itself. The importance of this factor is because of the point above. Namely, you want to ensure you have enough space on your flag to display the letters at the correct heights. If in doubt, the bigger the flag the better. The design of your flag impacts it’s legibility in at least two ways. The first is the font type or appearance of the font you choose to use. While your lettering height should meet certain minimums as described above, fonts themselves vary in legibility. Simply put, cursive fonts are much harder to read than block-type fonts. We recommend easy-to-read fonts in all cases. The other important consideration is contrast. Contrasting colors between your text color and flag color will significantly increase its legibility. For example, black and yellow are known to be some of the most contrasting colors whereas a pink font on a red flag is going to be harder to read. If you keep these few things in mind when designing and purchasing your flag you can rest assured that all those that pass by it will be able to clearly and quickly read it. If you’re still needing help and unsure whether your flag will be legible don’t hesitate to contact us about our free design services.