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

Iowa City Newspaper Lauds Projecting Signs Following CoSign Workshop at the American Sign Museum

Nate Kaeding is the Iowa City Downtown District’s retail development coordinator. He and other representatives from his city came to the American Sign Museum on February 20-21, 2017 to attend the CoSign workshop. CoSign is a program that connects merchants, designers and fabricators in order to create new and better signs, and promote economic development in communities.

Nate wrote a guest editorial for the Iowa City Press-Citizen’s February 21 edition under a headline of “2017 is the year of the projecting sign.” He writes abut the importance of having appropriate signage, and how Iowa City has changed its sign code to allow this. A portion of his editorial reads: ” The new creative signage will enhance the aesthetic and mood of downtown and add to our unique sense of place. This all will equate to more repeat customers at the stores, word-of-mouth marketing and economic vitality.”

To read the entire editorial, go to http://icp-c.com/2m5f3Mh  

 

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.

What are Some Guidelines for Electronic Message Center Resolution?

A critical aspect of any sign is viewing distance. The appropriate amount of detail varies greatly, depending on the distance from which the sign will be viewed. In digital printing, this “resolution” is determined by “dots per inch,” or DPI. The more closely an image will be viewed, the higher its resolution needs to be, which means the dots produced by the inkjet printer would need to be closer together, and there would be more of them within a defined space.

The same concept applies to electronic message centers. The individual LEDs function the same as the inkjet dots. The more detail you want, the more LEDs you would need with a defined space, and the decision would be based on the anticipated viewing distance. An electronic billboard 600 feet from the highway is different than an electronic message center built into the cabinet of a freestanding pole sign next to a two-lane road.

For electronic signs, this resolution is called “pixel pitch,” and it means the distance between the centers of individual LEDs, which are known as pixels. The distance also varies if the individual pixel is color (comprising different-color LEDs) or monochrome (one color). Here are some general guidelines for pixel pitch and viewing distance.

Pitch Range Viewing Distance
3-6mm up to 50 feet
6-12mm 50-100 feet
12-15mm 100-200 feet
15-20mm 200-400 feet
20-30mm 400-800 feet
30-40mm 800-1500 feet
More than 40mm More than 1500 feet

As for the size of letters and viewing distance, the standards for non-electric signs apply similarly — approximately 1 inch of letter height for every 50 feet of distance from which it would be viewed. This should be coupled with the speed of traffic. Allowing a viewing time of 20 seconds is ideal. Thus, if a car is traveling at 60 mph, the sign should be legible from a distance of 1734 feet. Generally, electric highway signs should be a minimum of 10 x 30 feet.

An article on this topic appeared in the May 2004 issue of Signs of the Times magazine.

What Difference Does an Angled Sign Make Versus a Sign that’s Parallel to the Road?

Elsewhere in this series of questions, the difference in conspicuity for parallel and perpendicular signs is calculated, along with the requisite minimum sizes for the letters of each. But what if the local sign code won’t allow a bigger sign, and not enough projection length for a legible perpendicular sign? Would a sign with at least some angle make a difference?

Frenchy’s Bistro was located on Anaheim St., a busy thoroughfare in Long Beach, California. As one of four tenants in a commercial building, it had two signs: a non-illuminated wall sign and a tri-color canopy that projected the maximum 30 inches.

As an alternative, Frenchy’s purchased a “double-faced” electric, cabinet sign, but the sign faces weren’t back to back, but angled out from the wall in a V-shape toward each other.

Before the new sign(s) was(were) installed, Frenchy’s had $279,000 in pre-tax income annually. After the sign was installed, sales increased 16% immediately. Over the next year, they increased an additional 32%. The owners surveyed their guests and determined the sign was directly responsible for 10% of all sales. The net income directly attributable to the sign for a year was $16,182. The following year, it increased to $21,360. This also meant an additional $8,865 in state and federal income tax.

Other calculations for the $5,700 sign included that its cost per thousand exposures (CPM, the standard way to compare different forms of advertising) was 15 cents. The cost per month for the sign was $121.11. At the time (2000), other CPMs were as follows:

  • A 30-second, prime-time TV ad: $18
  • A half-page, black-and-white newspaper ad: $10.80
  • A full-page, four-color magazine ad: $8.70
  • A one-minute, drive-time radio ad: $5.30
  • A 30-day, 30-sheet poster panel: $1.60

The full story appears in the September 2000 issue of Signs of the Times magazine.

Can a $500 Sign Generate $1.9 Million in Additional Revenue for a Health Clinic?

A Sarasota, Florida health-care clinic had a great suburban location, demographically. However, due to its location at the end of a two-story complex surrounded by oak trees, its fascia signage simply wasn’t visible from the interstate (0.2 miles away) or the four-lane frontage road with a median. The owner had a dozen other clinics, so he knew something was wrong with the amount of business the clinic was conducting.

The owner subsequently placed a very simple 10 x 24-inch. sign in plain site, with only the clinic’s name and the words “urgent care.” Within 24 hours, the number of clients nearly doubled. Over the course of a year, this increase would equal nearly $1.8 million in additional revenue. To read the full story, go to http://www.nxtbook.com/nxtbooks/STMG/sott_201411/index.php#/110

How Big Do the Letters on Signs, Parallel to the Road, Need to Be?

As noted elsewhere on this website, “visual acuity” and “conspicuity” and “cone of vision” are very important for signs, because motorists must be able to detect signs, read them and then react to them in a few seconds. So how much does the visibility change when a sign directly faces the driver (perpendicular to the road) versus one that may be flat against a building fascia (parallel to the road)?

The Larson Transportation Institute at Penn State University studied this phenomenon in 2006 through a grant from the United States Sign Council. Much of the work involved a literature review of prior, related research.

Several factors impact the necessary minimum size for letters, so that they can be detected and read quickly enough for the driver to react:

  • Number of lanes of traffic
  • Distance from the road to the sign
  • The motorist’s speed
  • The angle at which the sign can be read

USSC has published a chart that ranges from a sign that’s 10 feet from the road when the motorist is in the curb lane, versus a five-lane road in which the sign is 400 feet from the road. In the first instance, the sign’s letters need to be at least 4 inches tall. In the latter instance, the letters need to be a minimum of 90 feet tall.

This study, entitled “On-Premise Signs: Parallel Sign Legibility and Letter Heights, may be accessed at www.ussc.org.

What Does “Conspicuity” Mean for Signage?

Conspicuity for signage is determined by the contrast between the sign and its background. A sign must be conspicuous first, because, without it, the sign’s legibility and readability are moot points. While the appropriate size for signs is addressed on this website under the heading “How big should a sign’s letters be?”, conspicuity includes factors that only indirectly relate to size.

Anything that impedes the ability to detect a sign impacts its conspicuity: Trees, telephone poles, parked trucks and other signs are physical objects, and other factors include lack of illumination at night, driving west at sunset or east at sunup.

The two types of conspicuity are search and attention. Search conspicuity occurs when the motorist is actively looking for a gas station, food, lodging, etc. Attention conspicuity involves unexpectedly important signage, such as construction of “lanes closed ahead” signs. Generally, signs are three times more likely to be seen in search mode than attention mode.

“Cone of vision” is another major factor for conspicuity. The Southern California College of Optometry determined, for a motorist, their peripheral vision while still looking straight ahead while driving, is a maximum of 10 degrees left and right. Consequently, a sign’s distance from the road, called the “setback,” is absolutely critical in terms of conspicuity.

For example, at the same 10-degree viewing angle, a sign that’s 42 ft. from the road “disappears” from view when the driver is closer than 240 ft. If the sign is only 5 ft. from the road, at the same viewing angle, it remains in the driver’s sight until within 30 ft.

The Larson Institute of Penn State University, from 10 studies it has conducted between 1996 and 2010, has calculated a formula for determining when signs come into view in relation to setback:  L = D x 0.176, where L equals 10 degrees of “lateral offset” and D is the distance in feet of the sign at initial detection. Thus, if initial detection distance from the sign is 300 feet, 10 degrees of lateral offset would be 52 ft. Note that this offset is from the driver’s eye position, and not from some variable point. This is included in a 2015 publication called the United States Sign Council Best Practice Standards for On-Premise Signs. Go to http://www.ussc.org/pdf/USSCSignStandardsJune102015FINALEDITION.pdf

Similarly, Penn State has calculated how tall a sign should be, based on the distance from which it would be viewed. Using five degrees of vertical elevation, plus 3.5 ft. representing elevation of the average driver’s eye position above the road, a calculation of vertical sign-height limits, capable of providing comfortable detection over both long and short ranges, can be derived from the following equation:

H = D x .088 + 3.5, where H equals the sign-height minimum and D equals the distance in feet from the sign at initial detection. This is also included in the 2015 USSC publication.

Thus, if initial detection distance from the sign is 400 ft., the sign height must be at least 38.5 ft.

Signs that are perpendicular (facing) to the motorist, such as freestanding and projecting signs, are significantly more conspicuous than signs that are parallel to the road, such as fascia signs or letters attached to a building.

Penn State studied this phenomenon and found that 50-60% of the parallel signs weren’t even seen by motorists, even if they were three times bigger than corresponding perpendicular signs. Overall, perpendicular signs are generally four times more conspicuous than parallel signs.

Penn State has also calculated to what extent signs are blocked from view at specific distances, based on both the number of lanes of traffic, the amount of traffic and the sign’s setback. Numerous tables are included for the variables in the 2015 publication: which of the four lanes the motorist is in, the speed of travel, etc.

In a worst-case scenario, when a driver is in the curb lane of a four-lane highway, and the traffic flow is 1200 cars per hour, and the sign is 10 ft. off the road, a sign might be blocked from 77% of the drivers.