(WHTM) — Now that you know why highway signs are green, It is time to dive into another highway sign question.

Why are some signs in one font and other signs in another font?

Before that question is answered, let’s talk about the history of highway sign fonts.

The main typeface on signs for many decades is called Highway Gothic. This typeface is defined by the Federal Highway Administration (FHWA) Standards Alphabets for Traffic-Control Devices, which was published in 1948.

The font from this scene of Atlanta traffic has the older style Highway Gothic type font on their directional signage. (Getty)

There have been six variations of Highway Gothic. In recent years, the standard typeface for guide signs for higher-speed highways is Series E or Series E(M) of Highway Gothic. You can read about the most updated revision to the FHWA guide by clicking here.

In 2004, Penn State conducted research into a new style of typeface for roadway signage. The FHWA approved the interim use of a new typeface called Clearview. Clearview was a decade in development, according to Penn State.

“Inadequate signing can be a contributing factor in roadway crashes. Although Clearview was intended to help older drivers, our studies show that the appreciable gain in reaction time provided by the new typeface will be achieved by drivers regardless of age,” Martin Pietrucha, a civil engineer and director of the University’s Science, Technology and Society Program stated in 2004 when the typeface was first introduced.

Clearview makes reflective signs more readable. When light reflected off of signs with the old Highway Gothic font, it caused certain letters like lowercase A, E, and S to glow and become hard to distinguish, especially for elderly drivers.

An interstate sign in Pennsylvania written in the Clearview typeface. The font makes reflective signs more readable, especially at night. (Getty).

The new font solved that problem by creating more space inside the letters, so the glow when headlights hit them does not cover them up, Penn State noted. Pennsylvania was the very first state to implement new signs with the Clearview font. Later on, more states would start using the Clearview font in their signs.

But only 12 years later, in 2016, the FHWA found that Clearview font had a bad effect on negative contrast color orientations, for example, speed limit signs. Those signs in particular have black lettering on a white background. The FHWA stated at that time that all new highway signs would be reverted back to Highway Gothic.

The FHWA made it clear that public safety is not at risk because some signs are in Clearview, and the organization is allowing those signs to remain up until they are worn out.

However, in 2018 the FHWA reinstated the approval of the alternative letter style, Clearview, after the organization may not have had all the available information when it issued the termination of the Clearview font back in 2016.

As of 2022, you will see signs in both Highway Gothic and in Clearview.

See the difference for yourself! Drag the cursor to see the difference. Highway Gothic is on the left. Clearview is on the right. (Getty/WHTM)

Next time you are on an interstate, especially in Pennslyvania, take a look at the highway directional signs. You will probably see the two fonts during your drive!