By Devin Joslin, P.E., P.T.O.E
Traffic signs tell us where to go, what to watch for, and can save lives. But, there’s still more to them. Signs are designed and positioned for maximum effectiveness, which means the most minute details can make the difference. Here’s what you may not know:
1. Sign posts are designed to breakaway.
This means they minimize injuries and damage if hit by a car. Engineers know that run-off-the-road crashes occur, so signposts have a breakaway point so that when hit, they easily separate from the base. In addition to safety, this design is also useful because it means sign replacement simple; the base can generally be reused.
2. Signs are larger than we think.
Because we are often in our vehicles and at a distance when we see signs, it’s easy to underplay their size. Typically, the words on interstate guide signs are approximately 15-20” tall, and the signs themselves can be about 40 to 50 feet wide. For true scale, see the picture I took with a highway sign to the right.
3. There are only 13 colors allowed for traffic signs.
These colors are specified in the Manual on Uniform Traffic Control Devices (MUTCD), a book of federal sign guidelines. Of the 13 colors, 11 are actively assigned to a sign type while two remain open to use if needed in the future. States can also create their own MUTCDs and adjust these guidelines, although many remain the same or similar to the original.
4. There are anti-vandalism measures built in.
Unfortunately, signs are often the target of theft and graffiti. To combat this, signs have begun to include anti-theft measures and an anti-graffiti coating. Theft measures include bolts inside the sign’s structure to make unscrewing from the outside more challenging. (See the image to the left for an example of an anit-theft bolt.)
5. Blinking border lights can be strategically installed.
One safety measure that has recently gained popularity is blinking LED borders. Designated signs, such as stop signs and wrong way signs, can get this additional light-up outer edge to draw extra, needed attention if more drivers than usual are overlooking it and/or causing crashes. However, the borders are placed only where needed to avoid a driver desensitization.
6. Sign locations and conditions are constantly monitored.
It seems as if signs could just be placed and left, but that is not the case. Signs can be stolen, get vandalized, be hit, or simply wear out from weather. If the sign becomes damaged and is no longer communicating to the driver appropriately, crashes and agency liability could increase. To mitigate this, signs are tracked in systems like AssetGOV so conditions can be constantly monitored. This kind of asset management software allows users to track conditions and locations in real-time.
7. The rumored future of signs is extremely high-tech.
The world is rapidly changing and the theory is that physical signs will eventually be a thing of the past. Drivers would still need the information they provide, but one thought is that sign information will be electronically installed in cars. For example, if there was a large curve or stop approaching, the vehicle would know and alert the driver.