Kentucky has one Central Sign Shop where most of the state’s signs are manufactured, along with smaller shops in each of its 12 districts. The State’s current mandate has been ASTM Type IV or Type IX sheeting for most traﬃc signs. However, recent eﬀorts have been made to adopt a Type XI sign sheeting standard.
Reﬂective sign sheeting enables early visibility and legibility of signs, providing drivers suﬃcient time to react. The goal of bright, legible signs is to decrease the amount of time drivers’ eyes are oﬀ the road – particularly at night—making it a key element of safer roads. For this reason, traﬃc engineers aim to install highly visible, conspicuous, and durable sign sheeting on every roadway project.
There’s a difference in sheeting types
3M™ Diamond Grade™ DG3 Reflective Sheeting Series 4000 (3M Type XI) provides superior retroreflectivity at all distances and especially at greater disadvantaged observation and entrance angles. Series 4000 uses 100% eﬃcient full-cube prismatic technology to reﬂect almost 60% of available light back to motorists — almost double what 3M™ High Intensity Prismatic sheeting reﬂects. It is designed to better reﬂect the headlights of newer vehicles, providing more luminescence for older drivers, and to help truck drivers see road signs at greater distances and from compromised angles.
In order to determine the advantages of an upgrade to Type XI sheeting, the stakeholders performed a cost/benefit analysis to determine the financial impact along with the safety, warranty and durability performance benefits of Type XI.
After the analysis and a visit to a large sign fabricator to further learn about Type XI sheeting, transportation oﬃcials decided to install several demonstration Type XI guide signs to evaluate firsthand the visibility, legibility and retroreﬂectivity of the sheeting in all weather conditions. Providing Kentucky, the opportunity to analyze photos and videos, as well as in-person reviews of the sheeting during day and night, and dry and wet conditions.
Digital Printing: An Added Beneﬁt of Type XI Sheeting
Widespread input from sign shop employees confirmed that a digital printing solution using Type XI sheeting would make employees’ jobs easier, more eﬃcient, and more engaging. As a result, the Central Sign Shop purchased an HP 365 Digital Printer, and 3M provided sample printing material to illustrate the many options, features and beneﬁts of digital printing.
Kentucky transportation oﬃcials have instituted an ASTM Type XI standard for their traffic signs. Key decision criteria included:
- Maximum luminance – 3M Type XI sheeting returns nearly twice the amount of light as 3M Type IX with 100% efficient full-cube technology.
- Diminishing light supply from VOA headlights along with an aging population requires greater retroreflectance from sign sheeting to increase the returned light to the driver which is crucial in minimizing eyes off the road time.
- 3M Type XI provides superior performance at disadvantaged angle and difficult sign positions.
- Ability to create more complex logos easily and more efficiently through digital printing capability.
- After 12 years, 3M Type XI sheeting still provides greater reflective performance than newly installed 3M Type IX sheeting.
Editor's Note: Scranton Gillette Communications and the SGC Infrastructure Group are not liable for the accuracy, efficacy and validity of the claims made in this piece. The views expressed in this content do not reflect the position of the Roads & Bridges' Editorial Team.