User guide
Riding an e-scooter at night: visibility as a three-component system, eye dark adaptation, conspicuity around cars, route planning
76% of US pedestrian and 56% of US bicyclist fatalities happen in darkness, dusk or dawn (NHTSA / FARS), and the Austin Public Health / CDC e-scooter injury study found the typical injured rider is a male aged 18–29 riding on the street at night. This guide moves night risk from the «hope they see me» bucket into the managed-risk bucket: visibility as a **three-component system** (active lights + passive retroreflectors + conspicuous clothing), the physiology of dark adaptation (5–10 min for cones, up to 30 min for full rod adaptation — Webvision NCBI), **biomotion configuration of retroreflectors** (Wood et al., QUT Vision and Everyday Function: retro material on ankles/knees/wrists increases driver recognition distance 3× vs a vest with the same area and 26× vs all-black clothing), the difference between detection and recognition in driver perception, front-light modes by lumens and context (Cycling UK: 50–200 lm for lit streets, 600+ lm for unlit roads, 1000+ for high speed), German StVZO § 67 and UK Highway Code rule 60 as the two regulatory poles, route planning with lit streets vs dark cut-throughs in mind, protocol for losing your front light mid-ride, the alcohol + night risk (PMC: 63% of nighttime riders alcohol-involved vs 22% daytime, 77% head/face injuries with alcohol vs 57% without). ENG-first sources: NHTSA Pedestrian Safety + Bicycle Safety countermeasures, FHWA EDC-7 Nighttime Visibility, Webvision (NCBI), Wood et al. biomotion studies, UK Highway Code rule 60, German StVZO § 67, Cycling UK light guide, PMC e-scooter alcohol/nighttime studies.