The document discusses a project called CROWD4ROADS that aims to improve road maintenance and reduce CO2 emissions from passenger transport in the EU. It does this by combining ride sharing through BlaBlaCar with crowd sensing of road conditions using smartphone accelerometers through SmartRoadSense. This will help engage more people to monitor roads and induce more sustainable transportation behaviors. The project involves partners across 4 countries and will validate the approach through large pilots involving over 1 million people and 1 million km of roads.