Traffic speed enforcement is an important issue in order to guarantee public road security and to reduce the number of traffic accidents. Currently, this task has been partially carried out by vehicle speed-measuring devices, mainly including Doppler radar, lidar and inductive loop in China. To further evaluate the speed measurement performance of these devices widely used for evidentiary purposes in traffic speed enforcement cases, a traffic speed measurement standard equipment has newly been set up at No.S16 Expressway from Hangzhou to Shanghai in China. The standard equipment can be used for pattern approval field tests of vehicle speed-measuring devices in actual traffic, which can meet the requirements of the recommendation in OIML R 91 about the metrological field tests, with the advantage of the overall experiments of possible errors due to the complexity of factors affecting the result of measurement, such as shape of antenna pattern, reflection characteristics of target vehicle, change of lane during target vehicle passage through measurement region, braking or accelerating, presence of more than one vehicle, etc. This paper introduces the speed measurement principle of three kinds of vehicle speed-measuring devices, and studies the components of the standard equipment. A field testing experiment based on the standard equipment in actual traffic was designed and performed with 11 types of vehicle speed-measuring products as samples, including radar, lidar and inductive loop based devices, to evaluate their actual performances in actual traffic.