Congestion on freeways restrains its ability to provide smooth traffic flow. Normally congestion occurs when traffic volumes are considerably greater than the link capacity especially in the peak hours or in case of incidents that disturb the traffic flow, which either are denoted as recurrent and nonrecurrent congestion respectively. As a consequence, the freeway network performance is adversely affected in terms of reducing the speed, increasing the crash probability, increasing the travel time and increasing the vehicle emissions due to increase the fuel consumption. Since the structural solution is limited to many factors, ramp metering strategies have played a major role in freeways' traffic management systems. In the purpose of evaluating the effects of ramp control approach on congested flow at Istanbul freeways we summarize in the present paper the analyses conducted over a microscopic simulation-based environment where a local ramp metering strategy, ALINEA, is utilized online by integrating VIS SIM and MATLAB.