GENERAL PLAN OF TRAFFIC MANAGEMENT IN MAIN ROAD 5 BETWEEN MIKKELI AND VISULAHTI, THE STUDY OF PRESENT SITUATION

This study discusses the main road 5 between Mikkeli and Visulahti, which is a road section from Mikkeli to north. The most problematic area in this road section is the Visulahti tourist center and Huusharju residential area four-leg intersection. In 2000 study of traffic management on main road 5 between Mikkeli and Visulahti has been conducted. The study discusses the possible ways of traffic control and telematics, which could improve the traffic conditions of the road section. The study traffic surveys have been performed, including vehicle speed measurements, video recording and traffic counts. The goal of this study is, on the basis of the traffic surveys, to find out how the traffic conditions are changed depending on the time of the day and year. In addition, the possible traffic control measures to avoid the use of too low speed limits, are considered. Another goal of the study is to update the evaluation of the effects of the 2000 variable speed limit system, which has been designed to the road section, and to find out if there are any geometrical problems on the road, which could prevent the use of the speed limit 70 km/h in the Visulahti crossing. The vehicle velocity measurements were performed in four locations, in Launiala, Kinnari, Visulahti and Sairila. On the basis of the measurements, the traffic was the heaviest on Fridays to north and on Sundays to south. The average speed depended on the traffic volume. When the traffic volume increased, the average speed and standard dispersion decreased. However, when the traffic volume increased over 400 vehicles/hour the decrease in the average speed stopped. On some of the measuring points the dependence between the traffic volume and the average speed was not detected. On the basis of the video tapes of the Visulahti crossing, the delays on the Visulahti road were noticeably greater in summer than in autumn. In summer, when the main road 5 traffic was heavy, queues of few cars were formed. The most problematic direction was from Visulahti to the left. The longest waiting times in the queues were approximately 4-5 minutes. Queues which lasted several minutes formed during the hours between 4 pm - 7 pm. In autumn the traffic from Visulahti to the main road was minor, so queues did not form. The control bases of the variable speed limits were adjusted in this study. In Visulahti crossing, the variable speed limit system is based on 2 monitoring points on the main road and 1 point on the Visulahti road. When queues occur on the Visulahti road, the speed limits on the main road will be decreased. The entire road section variable speed limits system consists in addition of the main road and Visulahti measuring points, of one measuring point in Graani grade-separated junction, which observes the reservation of the exit ramp. On the basis of this study the problems on the Visulahti four-leg intersection are not major, and the variable speed limit system is not economically profitable.