People drive e-scooters on sidewalk in Lisbon, Portugal

People walk past an e-scooter left on the sidewalk in Lisbon, Portugal, Aug. 28, 2019. E-scooters may pose a potential threat to road safety if users violate traffic rules. Police are taking measures here against drivers who do not comply with safety regulations such as driving in pairs or not wearing helmets. (Photo by Pedro Fiuza/Xinhua)