Sign Retroreflectometer - Ultra 922

Mirolux Ultra 922

The Mirolux Ultra 922 is a portable, cost effective and easy to use device designed to measure the retroreflectivity of any type of retroreflective material associated with traffic signs and determine if minimum retroreflectivity requirements are being met as prescribed in the Manual on Uniform Traffic Control Devices (MUTCD).

The MUTCD defines the standards prescribed the Federal Highway Administration to install and maintain traffic control devices on all public streets, highways, bikeways, and private roads open to public traffic. The MUTCD is published by the Federal Highway Administration (FHWA) under 23 Code of Federal Regulations (CFR), Part 655, Subpart F.

The MUTCD, which has been administered by the FHWA since 1971, is a compilation of national standards for all traffic control devices, including road markings, highway signs, and traffic signals. It is updated periodically to accommodate the nation's changing transportation needs and address new safety technologies, traffic control tools and traffic management techniques.

MUTCD Sign Retroreflectivity Requirements

Sign ColorAdditional Criteria Sheeting Type (ASTM D4956-04)
Beaded SheetingPrismatic Sheeting
White on GreenOverheadwhite not approved; green ≥7white not approved; green ≥15white not approved; green ≥25white ≥250; green ≥25
Ground-mountedwhite not approved; green ≥7white ≥120; green ≥15
Black on Yellow or Black on OrangeFor text and fine symbol signs measuring ≥1200mm (48 in) and all bold symbol signsyellow/orange not approvedyellow ≥50; orange ≥50
For text and fine symbol signs measuring <1200mm (48 in)yellow/orange not approvedyellow ≥75; orange ≥75
White on RedMinimum sign contrast ratio ≥ 3:1 (white retroreflectivity / red retroreflectivity)white ≥35; red ≥7
Black on White-/-white >=50

Technical Design Discussion

The Mirolux Ultra 922 uses the ASTM standard "annular" geometry, measuring observation angles of 0.2 and 0.5 degrees simultaneously, with an entrance angle of -4 degrees. This patented (US Patent# 7,961,328) design allows the user to determine how bright a particular traffic sign will be to both traditional and high profile vehicles. In addition, the annular geometry means you will not have to take an average of two measurements with prismatic-type materials, further simplifying the measurement process.

The sensitive light sensor in the Mirolux Ultra 922 meets ASTM E1709 and ASTM E2540 requirements with the CIE standard human eye response in conjunction with the CIE illuminant "A" lamp.


Mirolux Ultra 922

Every Mirolux Ultra 922 is shipped in a watertight, dust-proof Pelican carrying case with the following accessories:

Click on the case at the right to view all components.

Mirolux Ultra 922


  • Measures signs to ensure compliance with the MUTCD minimum retroreflectivity requirements
  • Measures all types of retroreflective materials with a single measurement
  • Meets ASTM, CIE & DIN specifications
  • US Patent# 7,961,328
  • Utilizes annular measurement geometry which means no averaging of measurements on micro-prismatic material necessary
  • Intuitive digital liquid-crystal touch-screen display allows for quick and easy readings by any person with minimal training
  • Ease to read, measurement of retroreflectivity provides a clear pass/fail rating
  • Included V software easily integrates collected data with several of the top GIS software systems without a further technology investment
  • Dual observation angles of 0.2° and 0.5° for simultaneous measurements
  • Measurement time is less than 1 second
  • World-class photopic-corrected detector and source "A"
  • Requires only one reference standard without any correction factors
  • Self-contained commercially available battery
  • Built-in GPS
  • Made in the USA
Mirolux Ultra 922
Made in USAMade in USA