For the sake of traffic congestion prevention, the mark of Yellow Box Junction (YBJ), which refers to the mark of a yellow box with two diagonal intersection lines, serves to forbid vehicles from stopping at the junction area. Unfortunately, many drivers and riders still commit disobedience at the YBJ mark, and consequently, gridlock often occurs at the junction, particularly in big cities such as Surabaya. Therefore, this research was aimed at investigating the effectiveness of YBJtoward junction performance, YBJ standard appropriateness, and drivers’ or riders' knowledge of YBJ in Surabaya. The junction connecting the road of Margomulyo-Tandes Lor is considered beneficial to be used as the parameter of junction performance and YBJ mark disobedience level. For this reason, the researcher checked the standard conformity by distributing a questionnaire to know the knowledge level of the driver or rider in Surabaya toward YBJ.The research result demonstrated that YBJ was ineffective at the junction performance by a delay of 45.72 det/skr, and thus, the service level of the junction was E. In terms of correlation analysis, there was a close relationship between YBJ and junction performance. Meanwhile, the survey concerning the suitability ofYBJ, meaning that YBJ was ineffective. In terms of knowledge level, the survey indicated that the knowledge level of drivers or riders about the definition and function of YBJ was good enough, but they still do not know the sanction of YBJ mark obedience due to the limited socialization from Surabaya Government.