Optical Instruments

Last change: 09.12.2018

Measuring retroreflection of Markings, Signs and Clothing


High and increasing traffic loads are causing wear on pavement surfaces on roads and in airports resulting in wear and tear of the surface as well as the markings applied. This necessitate regular performance control checking which for markings can be done using a retroreflectometer. The nighttime visibility (RL, coefficient of retroreflected luminance) and the daytime visibility (Qd, luminance coefficient under diffuse illumination) can be quickly and accurately measured using the LTL devices from DELTA.

The LTL-M is a retroreflectometer for measuring the night visibility of road markings dynamically being mounted on the side of a vehicle This means that continuous measurements are carried out in moving traffic at normal speeds, typically 50 to 120 km/h. There is no need for safeguard measures nor will road traffic get bothered using a dynamic device.

Besides road markings, the measurement of night visibility of retroreflective foils, such as those used on traffic signs and safety clothing, are increasing in importance. DELTA has developed the RetroSign range of instruments for this purpose.



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ZTV M 13, BASt, Federal Highway Research Institute, road marking, day visibility, night visibility, retroreflection, reflection, RL, Qd, SRT, LTL, RetroSign, Delta Light & Optics, 30m geometry, air temperature, humidity, skid resistance, testing institute, static measurement, dynamic measurement, traffic signs, security clothing, DIN 1436, ASTM E 1710, EN 1463-1:1997, DIN EN 12899, ASTM E 1709