S30137 Microplastics Phase 4

This work order will help National Highways better understand and manage the growing environmental risks associated with microplastics and other emerging pollutants generated by the Strategic Road Network. Existing guidance and assessment methods were developed before the full scale of concerns around microplastics, particularly tyre wear particles, became apparent, meaning there are recognised evidence gaps in current policy and design standards. This project will provide robust, year-round monitoring of highway drainage systems to determine how effectively they remove these pollutants before they enter rivers and other sensitive water environments, while also identifying any contaminants that could pose environmental harm. The findings will directly inform future National Highways policy, drainage design standards and pollution mitigation strategies, supporting legal, environmental and reputational responsibilities. There is a clear urgency to progress this work as regulatory and public scrutiny of microplastics continues to increase, and the outcomes will provide the evidence needed to ensure National Highways remains proactive in protecting the environment and maintaining confidence in the sustainability of the road network.