pricing—struggled the rest of the month to get a permit. By the end of August, Citi Bike started designing a dockless prototype that could lock its own wheels based on whether the customer had paid. As part of a pilot program, Citi Bike also started testing 200 pedal-assisted electric bicycles, which soon became popular among customers. Additional e-bikes were planned to be added in advance of the 14th Street Tunnel shutdown, which would partially suspend service on the in Manhattan and under the East River to Brooklyn from 2019 to 2020. Lyft, which had acquired Motivate in July 2018, announced a further expansion of Citi Bike service in November 2018. The , five-year expansion would double the bike-share system's service area to . In addition, the number of bicycles would more than triple, from 12,000 to 40,000. This would make Citi Bike among the largest bike-share systems in the world. The Gothamist website, citing a Lyft employee, stated that electric bikes would make up the "vast majority" of the new bikes. In February 2019, it was announced that the Citi Bike system would have 4,000 electric bikes by that June, up from 200. Because of the popularity of the electric bikes, a $2 fee would be added to each electric bike trip starting April 27. However, on April 14, the company announced that all their electric bikes would be removed from service due to accidents while braking. In July 2019, Citi Bike announced a timeline for its phase 3 expansion, which would double its service area. At the time, new bike-share stalls were being installed in East Williamsburg, Brooklyn; Bushwick, Brooklyn; and Ridgewood, Queens, along the route of the BMT Canarsie Line, which serves the . By 2020, stalls would be installed in the remainder of Upper Manhattan (namely Hamilton Heights, Washington Heights, and Inwood) and in the South Bronx. Before 2023, new stalls would also be installed in southwest, southeast, and eastern Brooklyn, including Brownsville, East Flatbush, Kensington, Prospect Lefferts Gardens, Sunset Park, and the remaining portions of Bedford–Stuyvesant and Crown Heights. Stalls would also be installed in northwestern Queens, namely Sunnyside, Maspeth, Elmhurst, Jackson Heights, and Corona. That September 5, Citi Bike reached 91,529 trips, the highest-ever single-day ridership. In May 2020, the system expanded into the Bronx and further north into Manhattan. Amid the COVID-19 pandemic in the United States, Citi Bike recorded its 100 millionth ride