An emergency hammer is a safety device used in vehicles to break through window glass in an emergency.
It is a simple tool with a plastic handles and steel tip. Its primary use is for breaking through vehicle windows, which are often tempered, in the event of a crash which prevents exit through the doors. They are commonly found on public transport, in particular trains and buses. The example pictured also illustrates a cutting tool at the other end of the hammer. This is used for cutting through seatbelts in the event that they are inhibiting a passengers exit.
Emergency hammers are also known as bus mallets, dotty hammers, safety mallets, and bus hammers. Most emergency hammers are attached to a cable or an alarm device to deter theft or misuse.
Emergency hammers can be purchased by consumers to store in their personal vehicles to provide a means of escape should the doors become unusable, such as in a collision or if the vehicle falls into water and is sinking.