The recent deaths of several teenage e-bike riders in the US has raised concerns about the safety of these vehicles, and highlighted a lack of clarity around what legally constitutes an e-bike and its safety regulations. Federal and state regulations have recently been introduced in the US, establishing a three-tier classification for e-bikes with a maximum speed limit of 20mph for Class 1 and 2 bikes, rising to 28 mph for Class 3 e-bikes.