This review was conducted by Dr Chloe Perkins and Dr Rebecca Steinbach of the Cochrane Injuries Group in the Faculty of Epidemiology and Population Health at the London School of Hygiene and Tropical Medicine.Road traffic crashes are a major and increasing cause of injury and death around the world. Many crashes occur as a result of red-light running (RLR), which occurs when a driver enters an intersection after the traffic light has turned red. While most drivers obey traffic signals, the possibility for violations does exist, due to either driver distraction, aggressive driving behaviours, or a deliberate decision to ignore the signal. In the UK, over 67,000 motorists were given points for failing to stop at traffic lights in 2015. A recent survey found that about 25% of motorists admit to running a red-light in the previous year, which is equivalent to 9.3 million motorists. RLR can have severe consequences when it results in collisions that cause damage to vehicles and road users. Red-light cameras (RLCs) are an enforcement mechanism that permit police to remotely enforce traffic signals. In the UK, the cameras are usually placed on one arm of an intersection where a red light running problem has been identified. Unlike traditional manual enforcement methods which are resource intensive and high risk, RLCs operate continuously and without human intervention, freeing up officers to engage in other activities. They do not lead to potentially dangerous high-speed pursuits and they provide a physical record of all violations. Their mechanical nature also reduces the possibility of accusations of human bias, discrimination, or selective enforcement.This review concentrates on the implementation of red-light cameras. It updates and expands a previous Cochrane systematic review to provide a comprehensive account of red-light cameras evaluated worldwide. The review feeds in to the Crime Reduction Toolkit narrative on Red light cameras and was conducted by the Cochrane Injuries Group in the Faculty of Epidemiology and Population Health at the London School of Hygiene and Tropical Medicine.It is the eleventh in a series of systematic reviews delivered by the Commissioned Partnership Programme.A research protocol has been included below. If you would like to receive our College What Works updates, please email firstname.lastname@example.org and ask to be added to our distribution list.