The police reports are filled with face-first crashes into the ground — and some iconic high-plains flora. On the evening of March 24, a scooter rider cruising along a sidewalk near Denver “struck a large tumbleweed,” forcing the Spin scooter to a stop and pitching the man over the handlebars, according to a police report. The cause was bizarre, but the crash was typical: An encounter with a relatively innocuous obstacle sent a scooter rider hurtling headfirst, resulting in two broken teeth. “People are going over the handlebars, and they don’t have helmets,” said Chuck Temple IV, who has reviewed dozens of scooters for his full-time business, electric-scooter.guide. Scooters are causing a lot of injuries, and increasingly, their design is getting the blame.