All cats are grey at night – and this means that they are almost invisible. This is also true for objects and installations on public roads as their visibility will be poor during darkness. Therefore high retroreflection, also referred to as night visibility is an important factor in improving road and traffic safety.


But how can the quality of road markings be maintained over a long period of time?

Portable retroreflectomers like the ZRM-models of the Swiss manufacturer Zehntner GmbH provide spot-on high precision measuring values and are suitable for inspection of short route sections, for quality control during application, legally binding expertise and laboratory measurements in research and development.

However, if an area wide check-up of the complete road system of a whole region or state is planned, these spot measurements are of limited suitability. For a quick, complete and economical survey of the retroreflection of road markings, Zehntner developed the ZDR 6020 Dynamic Retroreflectometer RL.

For many years this measuring system has been used successfully in many countries, amongst others in Germany by the testing institute PBS Prüfinstitut und Bauüberwachung Siemund.

In the last four years the Berlin based company surveyed more than 20’000 kilometers of road markings across the country. "Most of all, my clients appreciate the smooth procedure and the reliable results.", says owner and general manager Karl-Heinz Siemund.

At first, Siemund was mainly driving directly on behalf of the road authorities, however, the safety and maintenance of the German road system is increasingly handed over to private enterprises in the framework of private-public-partnership projects (PPP), so now Siemund also counts notable German road marking contractors like straat 1 GmbH, Lorenz GmbH or Hima GmbH among his customers.

"The low effort and ease of use is particularly important for my clients.", states Siemund. "Because the ZDR 6020 measuring vehicle can circulate in the normal traffic flow at speeds up to 150 km/h without further ado there is no obstruction of traffic and additional costly safety precautions are obsolete. My customers receive the results readily processed in the form of graphs and Excel sheets. Furthermore, pictures are stored together with the measuring values at regular intervals, so the route can be assessed retroactively – a valuable tool for evaluating the results."

From the very beginning Siemund and his team have been sold on the ease of use and the performance of the ZDR 6020 "Above all the safe and easy one man operation is of utmost importance for our business because we save money and can offer our services at competitive prices."

The included software „MappingTools“ shows the results on well arranged digital maps and tables with pictures. The colour-coded depiction of the measuring values on the digital maps shows at a glance the state of the road markings and maintenance procedures can be planned effectively and economically. On top of this, „MappingTools“ can also display measuring values gathered with other Zehntner retroreflectometers like the portable road marking instruments ZRM 6013+ and ZRM 6014, as well as the traffic sign retroreflectometer ZRS 6060. Thus, „MappingTools“ is the hub where all information flows together for evaluation and decision making.

On top of this convenient standard data evaluation, Siemund developed an additional well arranged graphical depiction of the measuring values in the form of route bands which is also greatly appreciated by his clients. Since all data from „MappingTools“ can be easily exported into other data formats like e.g. Excel sheets, such custom-made solutions are generated quickly to meet every clients special requirements.


RL - bar diagram

ZDR 6020 Dynamic Retroreflectometer RL measurements displayed in a graphical depiction.


"The ZDR 6020 Dynamic Retroreflectometer RL is an indispensable part of our portfolio of services and we are fully satiesfied with the system." Comments Siemund. "Last but not least because of the competent technical customer liaison and support by the Swiss manufacturer Zehntner. It is important for us that the system is fully operational throughout the road marking season. Zehntner engineers perform all maintenance and calibration works at our desired deadlines and prevent losses due to long down times."

For more information on PBS Prüfinstitut und Bauüberwachung Siemund check out their website:


Details on the ZDR 6020 Dynamic Retroreflectometer RL and the other measuring and testing instruments for road markings of the Swiss Zehntner GmbH can be found here:


Author:         Ingrid Bloß, Application Consultant

Company:     Zehntner GmbH Testing Instruments, Schweiz

Telephone:    +41 61 953 05 50