Pavement design for the mitigation of non-exhaust emissions

Non-exhaust emissions (NEE) from road traffic are increasingly recognised as a dominant source of particulate matter in urban environments. While regulatory and research efforts mainly focus on tyres and braking systems, the influence of pavement characteristics on tyre and road wear particle emissions, remain comparatively underexplored.

Within Life NEEVE, the consortium is analysing how asphalt pavement design influences the tyre – road interaction and, consequently, the generation of wear particles. The abrasion process occurring at the contact interface leads to the formation of tyre and road wear particles, whose magnitude depends not only on tyre composition and driving conditions, but also on surface texture, aggregate properties and mechanical behaviour of the pavement.

In this framework, different asphalt configurations are being designed and evaluated under controlled laboratory conditions. The experimental programme covers surface macrotexture, drainability, skid resistance and resistance to wear together with key mechanical properties such as stiffness modulus, rutting resistance and fatigue performance. These parameters are directly related to frictional behaviour, energy dissipation and surface degradation mechanisms that influence particle release.

All things considered, a key development within this research has been a hybrid asphalt configuration conceptually positioned between a conventional SMA-11 and a PA-11 mixture. This open-textured SMA approach (OSMA-11) combines the mechanical robustness and structural stability of stone mastic asphalt with a controlled increase in macrotexture and void structure typically associated with porous asphalt. By adjusting aggregate gradation and internal structure, this solution achieves a balanced surface profile while preserving adequate load-bearing capacity and long-term durability.

The ongoing research phase will be followed by validation in pilot sections in the city of Murcia (Spain) and the integration of advanced measurement systems capable of capturing particulate matter (PM10 and PM2.5) at tyre level. Through this systemic approach, Life NEEVE project seeks to generate technical evidence supporting the development of low-emission pavement strategies aligned with European air quality objectives.