Emergency vehicle equipment is any equipment fitted to, or carried by, an emergency vehicle, other than the equipment that a standard non-emergency vehicle is fitted with (such as headlights, steering wheels, and windshield/windscreens). Visual warning devices Emergency vehicles of any kind (fire truck, ambulance, police car) are highly likely to be involved in hazardous situations, including relatively common incidents such as a road traffic collision. They are also required to gain access to incidents as quickly as possible, and in many countries, are given dispensation from obeying certain traffic laws; for instance, they may be able to treat a red traffic light or stop sign as a give way, or be permitted to break the speed limit. However, emergency vehicles usually are not able to treat a railroad crossing as a give way, because a train cannot be warned in time to stop before the crossing to let the vehicle through. Hence, one of the few things emergency vehicles must yield to are heavy freight and passenger trains. For these reasons, emergency vehicles in many countries worldwide, are fitted with visual warnings to alert members of the public (and in particular, other motorists and road users), either as they approach the vehicle, or it approaches them. Visual warnings can be of two types - passive warning or active warning. Passive visual warnings The passive visual warnings are usually inherently linked to the design of the vehicle, and involve the use of high contrast patterns. Older vehicles are more likely to have their pattern painted on, whereas modern vehicles generally carry the retro-reflective designs which reflect light from car headlights or torches (and was invented by 3M). Popular patterns include 'checker board' (alternate coloured squares, sometimes called 'Battenburg markings'), chevrons (arrowheads - often pointed towards the front of the vehicle if on the side, or pointing vertically upwards on the rear) or stripes (along the side - these were the first type or retro-reflective device introduced, as the original 3M reflective material only came in tape form). In some countries, in addition to retro-reflective markings, the vehicles are now painted in a bright yellow or orange colour underneath, in order to maximise visual impact. Another passive marking form is the name of the emergency service spelled out in reverse on the front of the vehicle (e.g. Ambulance or Fire). This enables drivers of other vehicles to more easily identify an approaching