cross-direction turns green. Some studies have confirmed more rear-end collisions where red light cameras have been used, while side collisions decreased, but the overall collision rate has been mixed. A systematic review summarized evidence from 38 studies and found that overall, red-light cameras are effective at reducing right angle crashes and related injuries, as well as total injuries, but they also lead to an increase in rear end crashes. In some areas, the length of the yellow phase has been increased to provide a longer warning to accompany the red-light-running-camera. There is also concern that the international standard formula used for setting the length of the yellow phase ignores the laws of physics, which may cause drivers to inadvertently run the red phase. History Red light cameras were first developed in the Netherlands by Gatso. Worldwide, red light cameras have been in use since the 1960s, and were used for traffic enforcement in Israel as early as 1969. The first red light camera system was introduced in 1965, using tubes stretched across the road to detect the violation and subsequently trigger the camera. One of the first developers of these red light camera systems was Gatsometer BV. The cameras first received serious attention in the United States in the 1980s following a highly publicized crash in 1982, involving a red-light runner who collided with an 18-month-old girl in a stroller (or "push-chair") in New York City. Subsequently, a community group worked with the city's Department of Transportation to research automated law-enforcement systems to identify and ticket drivers who run red lights. New York's red-light camera program went into effect in 1993. From the 1980s onward, red light camera usage expanded worldwide, and one of the early camera system developers, Poltech International, supplied Australia, Britain, South Africa, Taiwan, the Netherlands and Hong Kong. American Traffic Systems (subsequently American Traffic Solutions) (ATS) and Redflex Traffic Systems emerged as the primary suppliers of red light camera systems in the US, while Jenoptik became the leading provider of red light cameras worldwide. Initially, all red light camera systems used film, which was delivered to local law enforcement departments for review and approval. The first digital camera system was introduced in Canberra in December 2000, and digital cameras have increasingly replaced the older film cameras in other locations since then. Operation Red light cameras are typically installed in protective metal boxes attached to poles at