PURPOSES : This study aims to investigate the effect of the propagation time of variable message sign (VMS) information and drivers’ detour rate on the VMS performance under non-recurrent traffic states. METHODS: A microscopic simulation model (i.e., VISSIM and VISSIM COM User Interface) was developed at a location where VMS messages were most frequently displaced in 2018 from the Busan Regional Construction and Management Administration. The non-recurrent traffic states realized in this study were one- and two-lane close cases with scenarios involving multiple propagation times from 0 min to 20 min in 2 min increments and detour rates from 0% to 50%, in 10% increments. The measures of effectiveness are the average delay per vehicle, total travel time, and reduction rate of the total travel time based on the average value of 30 multiple simulation runs for individual scenarios. RESULTS:For the one- and two-lane close cases, the reduction rate of the total travel time increased as the propagation time shortened and the detour rate became bigger. The optimal (i.e., 0 min propagation time and 50% detour rate) and worst (i.e., 20 min propagation time and 10% detour rate) scenarios produced 41.1% (8.9 h) and 6.4% (1.4 h) and 26.4% (86.5 h) and 1.4% (4.7 h) of the total travel time for the one- and twolane close cases, respectively. CONCLUSIONS : The study results implied that the late propagation time and the low detour rate might not significantly influence the VMS system. Therefore, it is important to improve the information process time for the shorter propagation time and the reliability of the VMS information for a higher detour rate, which will result in a better VMS system performance.