Making white lines greener

Testing 10 different sustainable road markings

There are tens of thousands of kilometres of them in the Netherlands: white lines on roads, essential for the safety of road users. In industry jargon, these white lines are called road markings. We want to make a difference in terms of working sustainably. In the world of road markings, there is definitely room for improvement. The markings are a recurring product and are needed in large numbers.

After all, they do have to be replaced every now and then. We were looking for wear-resistant, sustainable road markings that are better for the environment, safer and quieter. So we offered companies a testing area for sustainable road markings in our InnovA58 living lab.

Small market

In the small market of road markings, we actively approached a number of suppliers. 4 companies in total ultimately tested 10 innovative road-marking products on the InnovA58 Innovation lanes on the motorway at Eindhoven: 3M, Veluvine, Coatec and BRTC. They were happy to be given the opportunity. They were required to show in advance the extent to which their markings were more sustainable than the standard white lines using an ECI (Environmental Cost Indicator) calculation.

What is sustainable about the tested road markings?

Developments in the sustainability of road markings generally revolve around the materials used:

• Lower temperatures generated;
• Use of bio-based and recycled components;
• Fewer materials used, for example long-dot profiled markings.

What did we test, and how did we do it?

There was a 2 year testing period, in which each product was exposed to traffic 2 seasons long. An 'extreme' test was also carried out under laboratory conditions. In this test, a car tyre simulated driving over the markings no less than 2 million times to measure their wear resistance.

The road markings were monitored to assess their essential functional properties: visibility, skid resistance, wear resistance and colour were the core criteria for comparing road markings. Improving these functional properties is important for a safer and more sustainable primary road network.

Other than that, improved road marking visibility helps to manage traffic flows and create recognisable patterns, particularly for systems such as ADAS (Advanced Driver-assistance Systems that help road users to arrive at their destination safely and without undue stress. These include Adaptive Cruise Control, driver drowsiness detection, lane departure warning and automatic emergency stop). The minimisation of contact noise prevents noise pollution when driving on quieter road surfaces, such as 2 course permeable concrete (ZOAB).

During the testing period, there were 2 points at which readings were taken: a baseline reading in 2022 and a 2^nd reading in 2023, around a year after the opening of the innovation lane for road traffic. The readings were taken by surveying companies M+P and KIWA/KOAC.

Results

The 3 most successful products revealed in the testing were clearly visible and indeed skid resistant, one of them even performing exceptionally well in the dark: a big advantage for road safety. Most of the products delivered in terms of sustainability. They are a little more expensive than traditional markings, but the cost is partially outweighed by a better ECI score.

Scaling up

InnovA58 and Rijkswaterstaats Innovatieloket (innovation service point) are aiming to apply innovations that were successful in testing more widely and frequently across a range of projects. That is a logical aim that contributes to making our work more sustainable. Sustainable road markings can help to reduce the environmental cost of roads. And yet, scaling up still presents challenges.

Spin-offs

This road marking test led to new initiatives, such as a study into reuse of road markings and, ultimately, a road map for sustainable road markings, to be completed in 2025. This chimes with our sustainability goals for 2030 and 2050.