Journal of Korean Society of Transportation ISSN:1229-1366(Print) 2234-4217(Online) 대한교통학회지

This study evaluates the effectiveness of a flashing speed limit sign that can provide different speed limits by time period for improving traffic safety in school zones which are located on arterial roads. To achieve this goal, we analyze and compare the speeds of vehicles in two school zones with crossing operated by the speed limit of 60km/h based on three cases, i.e., 1) before installation of the equipment, 2) equipment installed but not flashing and 3) equipment flashing. To analyze vehicle speed changes approaching the point where the signs were installed, observations are performed using the universal medium range radar (UMRR) system which can collect trajectories and speeds of detected vehicles. The effect of flashing speed limit signs is different depending on the geometry of the road and the surrounding traffic environment. In particular, flashing speed limit signs are found to be more effective when the driver is in an environment to recognize the signs well because the vehicle is relatively difficult to drive at high speeds. In addition, in the school zone on arterial roads, the vehicle is shown to be driving above the adjusted speed limit, indicating that additional strategies are needed to control it. This study contributes to the evaluation of the effectiveness of the flashing speed limit signs that have not yet been introduced in Korea and to the elicitation of the implications that can be referenced in the further construction of the signs.