Recently, research investigated different plastic materials capturing commonly used test sediment. Laboratory results were compared to field test results from a year-long Berlin study directly analyzing microplastics in road runoff and in the outlet of different small filtration treatment systems. Results substantiate large removal efficiency differences between quartz and microplastics, especially for gravity-based separators. These differences are marginal for filters. These findings may influence the development of future test protocols and the design of flow-through treatment technologies, which in turn can encourage acceptance of innovations that will prevent microplastics from continuing to degrade global waters.