Why Do Some Speed Limit Signs Have Fractions?

Drivers are familiar with all kinds of road signs, even those that don't always make sense. Through the years, reports of silly signs or even those that are mildly inappropriate have gone viral on social media platforms. While the Federal Highway Administration (FHWA) cracked down on PennDOT's funny road signs last year, you can still find a few in the wild that are still flying under the radar. In particular, some eyebrow-raising speed limit signs are still around, especially since they can add more value than trouble to the community that installs them.

At some point, you may have even encountered speed limits with odd numbers, such as fractions. A few years ago, an old parking lot in Chicago made waves for its 6 ⅞ mph speed limit, which caused a lot of people to do double takes. While it can be tempting to think it's part of something more compelling, the reality is that it's pretty simple why it's there. In an interview with Denver 7, Shea Properties senior real estate manager Sean Kidston said that the signs are there "just to be a little different." 

Since speed limits are set by local governments, there isn't really anything stopping them from turning them into memorable parts of their town. Similarly, we've mentioned how decimal points on speed limits have also been used to get people to pay more attention. Here are other ways it can be done and why it matters that local governments do it.

Apart from using fractions and decimal points, the U.S. Department of Transportation's Manual on Uniform Traffic Control Devices (MUTCD) actually has a whole section dedicated to making signs more conspicuous. 

Among them, some of the most common methods you've probably encountered on the road include solid or fluorescent yellow heads that say jarring words in all caps, like "NOTICE" or "NEW". There are also speed limit signs with diagonally striped borders in black and yellow (or something similar in fluorescent colors). In some cases, there are even flashier ways, like with cloth or reflective flags, which are typically angled in 45 degrees. While it also mentions the use of LEDs, it has many restrictions for it to be able to maintain a certain level of visibility. For example, the MUTCD specifically states that strobe lights are not allowed.

But while the method changes depending on the jurisdiction, the goal is always the same. When people find a reason to pay attention to speed limits, including minimum speed limits, it creates a steady flow of traffic. Overall, this makes for a safer environment for everyone involved, whether it's pedestrians, local wildlife, or other drivers on the road.