Roadside signage type size & readability

Luma Vine's picture

I am working on a roadside sign and the question of text size vs. whitespace came up. I am looking for some practical ideas about this topic. The font will be Fontin Sans regular and bold chosen to keep with brand standards and because of it's large x-height and good legibility. I added generous tracking as well, and the text is white on dark green. The viewing distance will be about 30 feet, in a car traveling maybe 35 miles per hour in town. I am using title case and someone suggested that the x-height (rather than cap height) should be the 3 inches from charts such as this:

However, I want to balance letter size with some other factors to keep readability and good layout considerations. In other words, how much do the following specifically enhance readability in this context, and how can good design principles be balanced with the desire to maximize letter size.

- Generous whitespace around the text. Letter size could go up if whitespace is given up.

- Using title case instead of all uppercase. Measured letter size would be increased by simply using all caps.

- Things like hierarchy, additional tracking and well designed layout make maximizing text size impossible. I have already eliminated as much text as possible, and tried to simplify things, but the lower case is around 2.5 inches, or maybe even a bit less.

Comments, thoughts and musings welcome.

hrant's picture

Hopefully James Montalbano will chime in - he's the expert.


Typography.Guru's picture

Whitespace around the text/lines: very important in this context!
Letter spacing: depends on the viewing distance. It’s the same principle as making the tracking in small print sizes larger. You want to make the space between the letters so, that at the largest possible viewing distance, letters can still be easily differentiated.

Case: What do you mean by »title case«?
In general you would want to use mixed case and uppercase/small caps only for VERY short pieces of information.

Hierarchy: Would depend on your design. Do you have some screenshots?
My personal experience with road signs: Hierarchies are best displayed thru position/spacing and color inlays. All those different font styles and sizes we use in print create too much distraction on a road sign.

You might want to check out my blog:

William Berkson's picture

Some information on the testing of Clearview Highway is here. However, because this is in town and the car is only 30 feet away, I don't know how important these fine points are. For what it's worth, Hermann Zapf has argued that many in-town signs are too big, and as a result are in effect visual pollution (my words).

JamesM's picture

I have limited experience with road signs, but one tip is to make a mockup to test. Of course this may be impractical if the sign is huge, but for a smaller sign it's often possible, or you can at least mockup a few words from the sign in actual size. Then hang it up and drive by in your car and see how readable it really is.

At a design firm I worked for we needed to create a sign to place in front of a client's office. We projected an image of our layout onto a big piece of white cardboard and drew it using markers, then hung the cardboard where the sign would go and drove by. We discovered the type was way too small. Saved us a lot of money and embarassment to find out before the final sign was fabricated.

.00's picture

30 feet at 35mph does not offer very much time to react. I would think you'd want to give the driver a bit more time than that to be able to make a decision.

I would suggest you make a full size mockup of the sign as close as possible to the final materials that you will use and set it up outside.

Letterpace is important, as is robust glyph shape, this is no place for delicate display lettering. Also important is space surrounding the legend. Do not crowd the primary legend. The more surrounding "noise" there is, rules, borders, secondary legends, the more the primary legends performance will deteriorate. Mixed case should be used.

William Berkson's picture

James Montalbano: Interesting. Was the negative effect of surrounding material tested for systematically, like the typeface?

Luma Vine's picture

Thanks so much for the great discussion! By title case I meant mixed case with all leading letter capitalized. The purpose is twofold, to raise awareness of the organization, and wayfinding. Here is a screenshot, the sign is 48x96 inches:

JamesM's picture

I would make the type and logo much bigger, and eliminate the phone number. It's just a distraction as they will not have time to write down a phone number while driving by.

Luma Vine's picture

Thanks. I should have mentioned that the phone number was requested so that if people are not able to find the location they can call. I don't think it is an option at this point to eliminate it. I was thinking that making everything a lot larger will do anything but clutter and eliminate whitespace. What specific goals are you addressing by suggesting making things larger? Maybe if you could describe the problem you see so that I can come to my own conclusions about the solution?

In general these are the questions I have:

- In these height charts, is the text size measured by cap height or x-height? Given that lower case letters are shorter, does that mean that text set in all caps will be more readable from a distance than lowercase of the same point size? (I assumed the opposite)

- What strategies do you use in balancing text size, tracking and whitespace to preserve readability while maintaining asthetic quality?

- Since it is easy to use these charts to be rigid about measured letter height minimums, how do you navigate and communicate the wholistic approach of incorporating ideas about whitespace, tracking, font selection, etc. instead of focusing solely on measured size of the smallest letters?

JamesM's picture

> What specific goals are you addressing
> by suggesting making things larger?

You said the sign will be viewed at 30 feet by someone traveling 35 mph. A car traveling at 35 mph travels 51 feet per second. So the sign will be visible for less than **one second**.

Even if we assume they're traveling slower, or can see if from a greater distance, we're still only talking about enough time for a very quick glance. So readability is a high priority, and it looked like the type & logo could be made considerably larger without making it look crowded.

Here's a quickie example. I made the type bigger, eliminated the phone, and centered the type on the right (since the type on the left is centered).

> the phone number was requested

If this sign will only be readable for a second or two while someone is driving by, you need to convince them that a phone number is a bad idea, and even potentially dangerous if someone tries to copy it down while driving.

Té Rowan's picture

And even with this, a driver has to rely on short-term visual memory to digest the message, which could well take 2-3 seconds. (Numbers from the rectal database.)

If ya gotta keep the tel., ya gotta, but try sticking it on the left half.

russellm's picture

I'd suggest, loose the "Then Right On Reed St."

Use a second sign at Reed Street instead.

Even better, use arrows on the sign(s) instead instead of verbiage. Or, if you must use use words, how about the name of the street they are to turn onto at the "next right" plus an arrow.

Depending on how close the sign is to the intersection, I can see how some people could become confused by the instruction "Next Right". Does it mean the street after the sign or the street after the street after the sign?

Luma Vine's picture

JamesM, thanks for your comments. I should have explained a bit more that 30 feet is very roughly the minimum viewing distance as one drives by, rather than the span of road from which the sign is visible. I would estimate that the sign is visible for more than 200-300 feet as you drive toward it, and from looking at charts, getting clearly readable to most people at 150-100 feet. That would give a viewing time of 4-6 seconds, and a reading time of 2-3 seconds, which is actually quite a long while for such few words in my opinion. Let's say perfectly adequate for communicating the main message of wayfinding and awareness, don't you agree?
I was reluctant to post the screen shot because I am not really looking for ways to toss out whitespace in favor of larger text as you handily achieved, but rather to understand the underlying principles and gain a better understanding of how to approach that balance. Unfortunately, you didn't give me enough insight into your thinking behind the changes you made, so I wasn't able to appreciate your motivation and goals. To be clear, I am not looking for ways to make the text larger** - the scale tool is easy enough to operate. Rather I was looking for insight and others' perspective on the relative importance of factors other than text size, and also whether to interpret the charts as x-height or cap height. Yes, fairly abstract and theoretical, but I pegged you lot as a heady group, and hoped to learn something. Looking at Ralf's blog and Clearview gothic has been very interesting! Thanks for those links. The idea of a mockup is spot on, I will try it out. I did some tests on screen standing across the room, but printouts would definitely help make it more realistic.

**My comments about "the desire to maximize letter size" were admittedly a bit misleading. Those were not my desires, but rather other folks involved in the project, who do have some experience in signage.

Russel, I posted only to see your previous post. Additional signs are out of the question I think. Putting one there would mean that it is in a front yard of a home, since it is all residential in the area.
This sign will not be on the corner, so I hope that people will understand to turn-as-soon-as-you-can at the end of this block. Is that really confusing? I often see billboards on the highway that say "next exit". Even if they successfully make that right, they will not see the building unless they take the right onto reed st. It really is just around the block, but without 2 turns you would miss it. I tried to add a bit of an arrow feel to the green background shape, but I can see how it's a bit more subtle on this background than on an actual sign.

JamesM's picture

> a reading time of 2-3 seconds

OK, that certainly sounds better.

> Unfortunately, you didn't give me enough insight into
> your thinking behind the changes you made

I wasn't trying to do anything profound. I just made the type easier to read from a moving car by reducing the number of words and making the type bigger. :)

The centering wasn't for readability, though, it was just a judgement call that if your logo uses centered type then it's more consistent to use centered type on the right side, too, rather than having mixed alignments.

But the only way to really find out the best size for the type is to make a mockup, put it in the actual location, and have some friends view it from a moving car. Perhaps your current type size will be fine. But my gut instinct is that making the type larger (like in my mockup) will make it easier to read. And if a sign can't be read, it can't communicate the intended message.

.00's picture

Your example is not a guide sign.

It is an advertisement.

Té Rowan's picture

Well, obviously. Signage is advertising, just not for products but for how to get there from here.

.00's picture

The advert contains much more "noise" on the sign, than a simple guide sign would contain. All of that extra noise will have a negative effect on the legibility of the main legends, but in this case I doubt it matters, if the driver can't read the sign in time he/she will simple miss the turn for the church. I wouldn't want to see this approach to designing warning signs.

JamesM's picture

I agree but the original poster said that advertising was part of the sign's purpose. ("The purpose is twofold, to raise awareness of the organization, and wayfinding".)

jabez's picture

In designing signs like the one above, I imagine that one would also have to take into account the environment that the sign will be placed in? For example, are there competing signs, billboards, etc?

I might define [raising awareness] and [wayfinding] as two separate objectives.
Raising awareness: Letting people know that the organization exists in the neighborhood
Wayfinding: Helping people to get to the organization

>That would give a viewing time of 4-6 seconds, and a reading time of 2-3 seconds, which is actually quite a long while for such few words in my opinion.

That seems somewhat optimistic to me. It might not be long at all*, especially if you consider all the things one must pay attention to while driving – other road users, traffic conditions, lights, the phone, radio, kids, etc. Unless the road is extremely clear, I often can't afford to take more than one or two quick split-second glances at a sign.

I'd imagine I might experience it somewhat like this:
First glance: Spot the logo
Second glance: Try to decipher the words

*Speaking from my limited experience as a driver (7 years)

This looks like it might be a helpful read:

I've never enjoyed math (equations always gave me a headache) so I'll leave it to the experts to decide whether those equations in USSC's "research-based" approach are useful.

DETERMINING SIGN SIZE – Calculation Methodology
The size of a sign is determined by the size and length of the message and the
time required to read and understand it. It can be calculated once the numerical
values of the five size determinants –Viewer Reaction Time, Viewer Reaction
Distance, Letter Height, Copy Area, and Negative Space – have been

The step-by-step process to determine sign size, which is explained below, is
useful not only as a calculation method, but also as a means of understanding
the elements involved in the calculation.

Area of Sign / Computation Process:
1. Determine speed of travel (MPH) in feet per second (FPS): (MPH x 1.47).
2. Determine Viewer Reaction Time (VRT).
3. Determine Viewer Reaction Distance (VRT x FPS).
4. Determine Letter Height in inches by reference to the Legibility Index (LI):
5. Determine Single Letter Area in square inches (square the letter height to
obtain area occupied by single letter and its adjoining letterspace).
6. Determine Single Letter Area in square feet: Single Letter Area in square
7. Determine Copy Area (Single Letter Area in square feet x total number of
letters plus area of any symbols in square feet).
8. Determine Negative Space Area at 60% of Sign Area (Copy Area x 1.5).
9. Add Copy Area to Negative Space Area.
10. Result is Area of Sign in square feet.

russellm's picture

One word; Euroface

Luma Vine's picture

Great resource jabez! Answered my questions:

"Negative space ideally should not be less than 60 percent of
the sign or background area."

"The USSC Standard Legibility Index is a numerical value representing the distance in feet for every inch of capital letter height at which a sign may be read. The table also reflects the 15 percent increase in letter height required when all upper case letters (all caps) are used instead of upper and lower case letters with initial caps, a difference in recognition distance documented in earlier studies by the researchers at the Pennsylvania Transportation Institute."

Emphasis added by me.

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