As stand-up electric scooters have rolled into more than 100 cities worldwide, many of the people riding them are ending up in the emergency room with serious injuries. Others have been killed. From a report: There are no comprehensive statistics available but a rough count by The Associated Press of media reports turned up at least 11 electric scooter rider deaths in the U.S. since the beginning of 2018. Nine were on rented scooters and two on ones the victims owned. With summer fast approaching, the numbers will undoubtedly grow as more riders take to the streets. Despite the risks, demand for the two-wheeled scooters continues to soar, popularized by companies like Lime and Bird. In the U.S. alone, riders took 38.5 million trips on rentable scooters in 2018, according to the National Association of City Transportation Officials. Riders adore the free-flying feel of the scooters that have a base the size of a skateboard and can rev up to 15 miles per hour. They’re also cheap and convenient, costing about $1 to unlock with a smartphone app and about 15 cents per minute to ride. And in many cities, they can be dropped off just about anywhere after a rider reaches their destination. But pedestrians and motorists scorn the scooters as a nuisance at best and a danger at worst.