Engineering:Emergency hammer

Emergency Hammer in a train, with the red spot in the window demarcating the preferred point of breakage.

An emergency hammer is a safety device used in vehicles or buildings to break through window glass in an emergency. Emergency hammers are also known as bus mallets, dotty hammers, safety mallets, and bus hammers. Many are attached to a cable or an alarm device to deter theft or vandalism.

It is a simple tool with a plastic handle and steel tips. Its primary use is for breaking through vehicle windows and vertical glazing, 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 and buildings worldwide (except North America including Canada and the United States). There can also be 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 passenger's exit.

Emergency hammers can be purchased by consumers in store for their vehicles, homes, hotels etc. to provide a means of escape should the doors/windows become unusable, such as in a collision, if the vehicle falls into water and is sinking or there is a fire within a building. However, people have been known to use these hammers to enter a car from the outside for purposes of burglary.