For the growing pressure of the urban freeway traffic, the frequently congestions and traffic accidents in the ramp afflux area, the plan of speed limiting and road increasing was proposed, after analyzing and optimizing the current existing afflux plan by using theoretical calculations and simulation experiment methods. Some quarantine and restrictions measures were taken in the ramp afflux area, the width of the primary and ramp lane was reduced appropriately, the vehicles speed was limited, and the vehicles were guided to go their own way, then the mutual interference could be less. Through the above measures, the traffic capacity of the ramp afflux was increased. The data of simulation experiments shows that this proposal excelle other proposals and is very effective based on the following traffic indicators, such as the traffic flow per unit time, the traffic speed and the queue length of vehicles etc. The proposal of "Speed Limiting and Road Increasing" is used in the urban express way with wide traffic lane.