This review was conducted by Dr Phil Edwards and Dr Chloe Perkins of the Cochrane Injuries Group in the Faculty of Epidemiology and Population Health at the London School of Hygiene and Tropical Medicine.Exceeding the speed limit is one of the most common criminal offences committed in the UK and can engender tremendous social harm. Speed limits on roads regulate traffic speeds by establishing a safe upper limit on vehicle speeds. Despite the very real consequences of exceeding the speed limit, according to the Royal Automobile Club Report on Motoring 2016, 46% of motorists admit to breaking the speed limit on 20mph roads and 44% of motorists admit to breaking the speed limits on 30 mph roads. Seventy percent of motorists admitted to breaking the speed limit of 70 mph on motorways. Efforts to reduce speeding behaviour have traditionally focused on the "3Es": Education, Engineering and Enforcement. Enforcement measures focus on ensuring that the public adhere to the posted speed limits through the automated or manual monitoring of traffic speeds. Enforcement of traffic speed limits needs to be such that drivers believe that they will be caught if they exceed speed limits; yet police cannot be present on all roads at all times. In many countries, there is therefore an increased use of automatic speed enforcement, using speed detection devices such as cameras. This review concentrates on the implementation of automatic traffic speed enforcement using fixed and mobile cameras to enforce speed limits. It updates and expands a previous Cochrane systematic review to provide a comprehensive account of automatic speed enforcement devices evaluated worldwide. The review feeds in to the Crime Reduction Toolkit narrative on Speed 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 eighth in a series of systematic reviews to be 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 email@example.com and ask to be added to our distribution list.