Skip to content. | Skip to navigation

Equipment for Quality Control and R&D+i

RetroSign GRX retrorreflectometer

RetroSign family of instruments the most frequently used Retroreflectometer for signs.

The GRX retroreflectometer measures nighttime retroreflection of traffic signs, high visibility clothing, license plates and reflective tapes. It is a handy instrument for use on the roads and in production. GRX is the new instrument in the RetroSign family that over the years has become the most widely used solution worldwide for measurements of traffic sign retroreflectivity and a defacto standard in many regions of the world.

GRX is intuitive in use. Measurements are taken in one second and data is easily transferred to a PC or a tablet. Built-in options for photos of signs, barcode reader, QR code reader, GPS, instrument rotation and tilt, sign facing direction and MUTCD sign library for automatic pass / fail of sign performance extend the instrument versatility significantly.

A tablet extension allows the user in the field to transfer data for back-up, processing and presentation including mapping as well as sending data instantly to the company back office.


Scalability of GRX- also after purchase – is an extremely powerful feature. Users can through software licensing upgrade their system in the field as their needs change.

Point based technology for correct results with modern sheeting

From the days of glass-bead based, symmetrical sign sheeting, two methods of measuring retroreflectivity exist, the annual geometry based method and the point geometry based methods. However, with modern microprismatic sheeting, a technology that is nonsymmetrical, only the point based method provides correct measurement results.

GRX employs the point geometry based method, thus ensuring correct measurements in addition to allowing the user to detect if direction sensitive microprismatic material has been correctly mounted.

Highly versatile in applications

RetroSign GRX is offered with up to 7 observation angles and a standard entrance (also called illumination) angle allowing for ASTM (-4o) or CEN (+5o) geometry. Standard models include GRX-1, GRX-3 and GRX-7. Entrance angles can be supplemented with 10°, 20°, 30°, 40°, 45° extensions.

Other features are: automatic color recognition, color contrast (background and legend colors), fast calibration using scan of QR code and data presentation in existing software programs.

The internal memory stores more than 2 mio. readings excl. photo or more than 2.000 measurements with photo allowing for many hours on the road before data transfer is needed.
The RetroSign instruments operate with a reproducibility of better than+/- 5 % and a repeatability of +/- 2 %.

RetroSign instrumets are calibrated using references from DELTA’s DANAK/ ILAC accredited laboratory with traceability to PTB and NIST.


Referencia Description Quotation Request
DEL-GRX1 Delta GR-X1 retroreflectometer Quotation Request
DEL-GRX1ASTM Quotation Request
DEL-GRX3 Delta GR-X3 retroreflectometer Flexible Angles: 5º/ 0.33º,0.5º, 1.0º Quotation Request
DEL-GRX7 Quotation Request
DEL-GRX7ASTM Quotation Request
DEL-GRXSEGURIDA Quotation Request
DEL-GRX10 Quotation Request
DEL-GRX20 Quotation Request
DEL-GRX30 Additional Entrance angle adapter 30º Quotation Request
DEL-GRX4 Additional Entrance angle adapter -4º for ASTM Standard Quotation Request
DEL-GRX40 Quotation Request
DEL-GRX45 Quotation Request
DEL-GRX5 Quotation Request
DEL-GRXALARGADO Extension pole w/pole Quotation Request
DEL-GRXBATERIA Quotation Request
DEL-GRXCARGADOR Quotation Request
DEL-GRXDIRECTIO Quotation Request
DEL-GRXFOTO Photo of Signs Quotation Request
DEL-GRXGPS Built-in GPS Quotation Request
DEL-GRXLECTOR Barcode & QR Code Reader Quotation Request
DEL-GRXLIBRERIA Quotation Request
DEL-GRXLICENCIA Quotation Request
DEL-GRXPATRON Quotation Request
DEL-GRXROTACION Quotation Request
DEL-GRXWIFI Quotation Request


EN 12899, EN 20471, ASTM E 1709 y ASTM E 2540 y ASTM E 1809.

Maintenance service and calibration

Contact us