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       Local councils in Scotland are still using a lot of paint to mark roads, which is damaging to the environment, according to The Ferret.
       We asked all 32 councils in Scotland about the types of paint they use, and 24 councils responded that the paint they use is either all or mostly toxic thermoplastic paint. Eight local councils did not comment.
       The European Commission says cold plastic surfaces are safer, cheaper and more environmentally friendly. However, many local councils still use thermoplastic paints, which can have a global warming potential that is up to 136 per cent higher than alternative paints. Countries such as Austria and Switzerland have phased out thermoplastic surfaces, but 95 per cent of UK roads still have thermoplastic surfaces.
       The environmental impact of thermoplastics is not only due to their low durability, but also the fact that they must be used in a molten state, meaning that mobile equipment (usually trucks with open flames) is needed to maintain the material temperature at around 200°C.
       Cold plastic is more durable and does not require frequent replacement. This reduces the frequency of construction zones on the road and helps reduce accidents by improving visibility and keeping the road clear for longer.
       A report published by Transport Scotland in 2015 acknowledged problems with the “durability of thermoplastic road markings”. The report said a Glasgow contractor had suggested using cold plastic paint as an alternative.
       Cold plastic (…) is an environmentally friendly solution for road markings. The environmental impact is low due to its durability and the possibility of extending its service life by renewing it with a thin layer.
       In 2018, the European Commission (EC) published a report analyzing the study by the Austrian Institute of Industrial Ecology. The European Commission concluded that the cold plastic road marking system is the most sustainable solution for Austrian roads.
       The report compares thermoplastic coatings and cold plastic coatings. The report says that while the global warming potential can vary depending on the coating layer thickness, thermoplastic coatings can have an environmental impact that is 54 to 136 percent greater than cold plastic coatings.
       Other studies also show that cold plastic paint is safer than other paints because it has a longer lasting reflectivity.
       Winters in European cities are colder than in the UK, and cold plastic is used even in busy urban areas. Zurich is an example. “The amount of preparation work for the companies doing the marking is much greater and therefore not interesting from an economic point of view,” said commission spokesman Heiko Ciceri. “In the morning, workers first have to boil the paint and then apply it hot to the street. Working with this hot substance is not safe for the employees.”
       Chicheri explains that cold plastic was chosen for its ease of handling, environmental friendliness, durability and cost.
       Dr Alexander Klein, who works for Röhm, a global supplier of cold plastic raw materials from Germany, has published a peer-reviewed study on the sustainability of road markings. He said: “Cold plasticising… offers an environmentally friendly solution for road markings. It has a lower environmental impact due to its durability and the possibility of extending the service life by thin-layer renewal.”
       Klein added that thermoplastics are less resistant to wear, so they need to be used in larger quantities. This, combined with the energy needed to keep the coating molten, means that “thermoplastics have higher CO2 emissions than cold plastics,” he said.
       In Stockholm, both hot and cold plastic are used for road markings, although there are reasons for this. The Stockholm City Department of Transport said: “Some people use more cold plastic, but we use more thermoplastic because we use studded tires in the winter. Studded tires can puncture cold plastic, which significantly reduces durability. Without studded tires, cold plastic usually lasts much longer than thermoplastic.” In the UK, studded tires are illegal in urban areas.
       There is no mention of cold plastic in the Scottish and English regulations and there are currently no plans to introduce a test for cold plastic coverings.
       A Glasgow City Council spokesman said: “We have traditionally used thermoplastic for road markings in Glasgow. I understand this method is considered effective in the weather conditions that the city regularly experiences.”
       An East Lothian County Council spokesman said council officers had attended a demonstration of road markings using cold plastic but this had not resulted in a switch to the product as “they noted that the long curing time of the product (30 minutes) made it unsuitable for use on busy roads”.
       The Department for Transport insists that UK roads meet European standards. A spokesman said: “The Department for Transport does not dictate to authorities what materials should be used for road markings.”
       A Transport for Scotland spokesman said the agency did not have a clear position on the use of thermoplastic road markings over other products.