National Academies Releases Nighttime Overhead Signage Luminance Levels

The National Academies Press has issued an 80-page report entitled “Guidelines for Nighttime Overhead Sign Visibility.” It includes a chart that’s headlined “Luminance Levels for Overhead Signs.” It lists five different visual complexity levels, ranging from a dark rural area to a commercial downtown district. It then suggests minimum luminance levels in terms of candelas per square foot and square meter. The suggested brightness levels at the most complex setting are 10 times higher than for the rural setting.

You can download the entire report at https://www.nap.edu/download/23512

Texas/Pennsylvania DOT Studies Says Clearview Font Improves Sign Legibility

A study conducted jointly by the Texas and Pennsylvania Departments of Transportation concluded that the Clearview font increased the visibility distance for drives by 12% versus the existing Series E Modified font.

In 1994 the Federal Highway Administration determined that highway signs were no longer visible enough for a population that included older drivers. Over the next decade, the Clearview font was developed. Subsequently, the Texas and Pennsylvania DOTs conducted separate studies to see how effective the Clearview font was.

The full report on this font can be found at http://onlinepubs.trb.org/onlinepubs/trnews/trnews243RPO.pdf

Should Signs be Regulated as Lighting Devices?

The answer is a very clear “no.” An article in Signs of the Times magazine explains that electric signs are not lighting devices, per se. Their purpose is not to provide light, but to provide messages. Thus, they should not be regulated as lighting devices. Electric signs need to be bright enough to be legible, but if they’re lit too brightly, then they become less legible. Thus, the sign industry has consistently provided electric signs with appropriate brightness, in order to serve their customers. The article explains these factors in much greater detail. You can read the entire article at http://www.nxtbook.com/nxtbooks/STMG/sott_201601/index.php#/66

Penn State to Present Lighting Study at American Planning Association’s 2017 National Planning Conference

Penn State University’s Philip Garvey, the Senior Research Associate at the university’s Larson Transportation Institute, will be a featured speaker at the American Planning Association’s 2017 National Planning Conference. His session, entitled “A Guide to National Sign-Illumination Standards,” will be presented on Saturday May 6 at 2:30. He will be joined by his colleague, Jennie Nolon Blanchard, and Cleveland State University Professor Alan Weinstein.

The APA website’s preview of the session states, “Take the guesswork out of developing lighting regulations for signs. Learn about new, first-of-their-kind national sign-illumination standards, based on research conducted at the Larson Transportation Institute at Pennsylvania State University.”

What has the Federal Highway Administration said about Off-premise Electronic Message Centers?

The 1965 Highway Beautification Act established federal guidelines for off-premise signs (billboards) located within 660 feet of federal highways. When “changeable Electronic Variable Message Signs (CEVMS),” (typically called electronic message centers, or EMCs, in the sign industry), began to become more commonplace, individual states began to establish agreement (Federal/State Agreements — FSAs) with the Federal Highway Administration (FHWA). Terms like “flashing,” “Intermittent” and “moving” were used in an attempt to describe the CEVMS.

In hopes of establishing more standardized criteria, the FHWA’s Office of Real Estate Services, on July 17, 1996  “issued a memorandum to Regional Administrators to provide guidance on off-premise changeable message signs.”

The FHWA states, “The policy espoused in the July 17, 1996, memorandum was premised upon the concept that changeable messages that were fixed for a reasonable time period do not constitute a moving sign (emphasis added). If the State set a reasonable time period, the agreed-upon prohibition against moving signs is not violated. Electronic signs that have stationary messages for a reasonably fixed time merit the same considerations.”

Then, more than a decade later, on September 25, 2007, the FHWA issued a second memorandum, called “Guidance On Off-Premise Changeable Message Signs.” It begins by saying “The purpose of this memorandum is to provide guidance to Division Realty Professionals concerning off-premises changeable message signs adjacent to routes subject to requirements for effective control under the Highway Beautification Act (HBA) codified at 23 U.S.C. 131. It clarifies the application of the Federal Highway Administration (FHWA) July 17, 1996, memorandum on this subject.”

It then states, “Pursuant to 23 CFR 750.705, a State DOT is required to obtain the FHWA Division approval of any changes to its laws, regulations, and procedures (emphasis added) to implement the requirements of its outdoor advertising control program. A State DOT should request and the Division offices should provide a determination as to whether the State should allow off-premises changeable Electronic Variable Message Signs (CEVMS) adjacent to controlled routes, as required by our delegation of responsibilities under 23 CFR 750.705(j).”

It then suggest standards for the timing between messages and the dwell time for messages.

“Based upon contacts with all Divisions, we have identified certain ranges of acceptability that have been adopted in those States that do allow CEVMS that will be useful in reviewing State proposals on this topic. Available information indicates that State regulations, policy and procedures that have been approved by the Divisions to date, contain some or all of the following standards:

  • Duration of Message
    • Duration of each display is generally between 4 and 10 seconds – 8 seconds is recommended.
  • Transition Time
    • Transition between messages is generally between 1 and 4 seconds – 1-2 seconds is recommended.”

How is the Size of Signs Measured?

The most common restriction in sign codes concerns the size of signs. This includes such considerations as the “setback,” (distance away from the road), the height and the dimensions of the sign itself. When the sign is a rectangle, and the copy fills it,  it’s easy — height x width. A 4 x 6-foot sign is 24 square feet.

But what if the sign is an irregular shape, or if the copy only fills a fraction of the sign face? What if the sign is individual channel letters on a wall? What if a backlit awning includes a logo? In all of these situations, do you measure the entire polygon, or just the portion that includes a logo or text?

What if the letters include upper- and lower-case letters, which means ascenders and descenders? Do you measure a rectangle around this “irregular” shape?

If the sign code establishes relatively small maximum sizes for signs, and measures all signs as rectangles, does this curtail creativity in design, because the merchant feels compelled to make the necessary letters as large as possible in order to achieve maximum visibility? Does this discourage round, triangular, oval and other shapes of signs?

The International Sign Association website has a section on measuring signs. You can access it at http://www.signs.org/LinkClick.aspx?fileticket=iAfIQfU-zL8%3d&tabid=1459

What Types of Signs are Most Commonly Used?

One of the most significant ways to divide the sign industry is into “electric” signs (which have internal illumination) and “commercial” signs, which are non-illuminated. For approximately three decades, a trade journal for the sign industry, Signs of the Times, conducted surveys of sign companies as to how their businesses were faring. These were called State of the Industry (SOI)reports. One of the stock questions was about the types of signs each company sold.

For electric signs, “cabinet” signs (essentially, enclosed plastic shapes with fluorescent or neon illumination inside) and “channel letters” (three-dimensional, individual letters shapes with the open area filled with neon or LEDs, and plastic that covered both the lighting and opening) have been the staples.

For commercial signs, banners and vehicle graphics have dominated.

In Signs of the Times’ most recent Electric SOI report, sign companies said channel letters accounted for 32.3% of their overall business. Cabinet signs were next at 26.3%. Third were “main identification, freestanding signs,” which meant they were set on the ground and weren’t attached to a building or any other structure, at 19.3%. Electronic message centers (EMCs) rated fourth at 10.3%. The full report can be read in the online edition at http://www.nxtbook.com/nxtbooks/STMG/sott_201407/index.php#/78

In Signs of the Times’ most recent Commercial SOI report, respondents said vehicle graphics (which includes the recent popularity of “wraps”) account for 26.7% of their business, followed by banners at 18.7. Next came “dimensional signs” (routed, carved, sandblasted, etc.) at 19.1% and window graphics essentially the same at 9.9%. The full report can be read in the online digital edition at the following link.http://www.nxtbook.com/nxtbooks/STMG/sott_201408/index.php#/72

What Types of Lighting are used to Internally Illuminate Signs?

The three primary types have been fluorescent, neon and LEDs for at least two decades, but the ratio of each has drastically changed. An industry trade journal, Signs of the Times, has traditionally tracked these changes through industry surveys. Its most recent such survey was published in its March 2015 edition. It notes that (Table 4), in 2014, sign companies reported that LEDs illuminated nearly 60% of all electric signs. In contrast, that figure was 14.7% in 2006. Over that same time period, the percentages for fluorescent and neon dropped from 44.5% to 25.6% and from 34.1% to 12.3%, respectively. The full report can be read in that magazine’s online, digital edition at the following link.  http://www.nxtbook.com/nxtbooks/STMG/sott_201503/index.php#/76.

Will GPS Make Signs Obsolete?

In 2008, a satellite-navigation specialist, Colin Beatty, presented a 27-slide PowerPoint presentation to the Sign Design Society, England’s leading environmental graphic design association. He asked the rhetorical question in his title:.  “Could personal navigation systems herald the demise of much fixed signage?”

In a column published in The Slate, author Julia Turner explores this question by interviewing both GPS-oriented companies and wayfinding-sign designers, including Craig Berger from the Society of Environmental Graphic Designers. Craig also serves on the board of the Academic Advisory Council for Signage Research and Education (AACSRE). To read the full article, go to http://www.slate.com/articles/life/signs/2010/03/a_world_without_signs.html

Penn State Study Examines Font Legibility

The Larson Transportation Institute at Penn State University conducted a study on font legibility through a grant from Gemini Inc. (Cannon Falls, MN), a manufacturer of dimensional letters. The following is the Executive Summary from the report. For information about the full report, contact Philip Garvey at pmg4@psu.edu.


Background and objectives

The enormous font selection available for on-premise signs fosters creativity, but also limitations, because of the unknown of a given font’s legibility at various distances. Although a small number of studies have broached this topic, this research effort is intended as the first to address the visibility of a large set of existing on-premise fonts.

Laboratory experiment

Method

The study was conducted at Penn State. Sixty-four signs were tested, using 34 unique fonts. The fonts were displayed as scale-sized, one-word, on-premise signs on a high-resolution computer monitor. Sixty-four subjects from 19 to 87 years of age participated. The legibility distance of each font was determined, and the effects of age, uppercase vs. lowercase, serif vs. sans serif, word-superiority, and art/word combination were evaluated.

Age group effect

The subjects were divided into three age groups. Not surprisingly, and consistent with earlier research, the young group and the middle age group were both able to read the signs from further away than the more elderly group.

Font effect

Large differences in font legibility were found. Gill Sans uppercase provided the best legibility, while Mistral lowercase had the worst. Also, simply choosing a font with a 5-ft./in. or larger ratio of distance to letter height insures better legibility, both statistically and practically.
 

Case effect

For all 31 fonts presented in both upper- and lower-case conditions, the upper-case words were more legible. In 22 of those cases, that difference was statistically significant.

Serif vs. sans-serif effect

There was no statistical difference between the serif and the san-serif fonts when shown in uppercase. A statistically significant effect was found in the lower-case analysis; however the difference was not practically significant.

Font family effect

Several fonts tested had more than one “weight,” such as bold or condensed.  The upper- and lower-case fonts were analyzed separately with the following results:

  • For upper and lower case, Times Bold was significantly more legible than Times New Roman.
  • For upper and lower case, Optima Bold was significantly more legible than Optima.
  • For upper and lower case, Garamond Bold was significantly more legible than Adobe Garamond.
  • For upper case, Helvetica was significantly more legible than Helvetica Bold, Helvetica Light and Helvetica Medium Condensed. Also, Helvetica Bold was more legible than Helvetica Light. For lower case, Helvetica was more legible than Helvetica Bold and Helvetica Light.

Word superiority

The 64 words showed large differences in legibility. The most legible word was Sunday, which was more than twice as legible as the least legible word, Crawfordsville.

Words and art

All of the signs tested included words and a graphic element. In 10 instances, the graphic directly related to the word (e.g., a drawing of a flower and the word “Flower”). This relationship minimally impacted sign readability.

Summary

This research sought to determine the relative legibility distances of a large set of fonts used on on-premise signs.  It allows users to compare legibility distances and make an informed decision about which font to use on their signs. Several results are clear:

  • Although font selection can significantly impact on-premise-sign legibility, many fonts have equivalent legibility.
  • Case (upper vs. lower) sometimes, but not always, can greatly impact sign legibility. Upper case often performs significantly better than lower case, at least under this study’s conditions.
  • The choice of serif vs. sans serif alone doesn’t measurably affect legibility.
  • Font weight can dramatically impact the distance from which a sign can be read. Fonts from the same family (e.g., Times) can have dissimilar legibility.
  • Word selection can greatly impact sign legibility. Not surprisingly, simpler, shorter words can be read at greater distances, regardless of font.
  • Matching a word to an image or graphic on a sign doesn’t, generally, positively impact legibility.