ASE(Average speed enforcement) system is one of the unmanned traffic speed enforcement devices under the Road Traffic Act, has been installed continuously since it was first introduced to the Seohae Bridge in 2007 for the purpose of reducing traffic a...
ASE(Average speed enforcement) system is one of the unmanned traffic speed enforcement devices under the Road Traffic Act, has been installed continuously since it was first introduced to the Seohae Bridge in 2007 for the purpose of reducing traffic accidents. It is possible to intall the ASE enforcement system with the budget of the Road Management Agency, so it is expected to be expanded more actively in the future.
Many studies have shown that the ASE installed in this way greatly contributed to the reduction of speeding accidents in terms of traffic accidents on freeways, but it is known that there have been few studies on the effect of ASE on traffic flow, especially on the flow rate.
The section where the ASE system is installed on a one-way two-lane freeway has a relatively large speed deviation compared to where the point speed enforcement camera is installed, there are many hilly sections, so there are many tunnels, and the ratio of heavy vehicles is relatively high.
In this characteristic environment, the mandatory speed deceleration at the start point of enforcement, which is a specific point of ASE section, lowers the operating speed (V85), and it was judged that the maximum flow rate may change by affecting the spacing between vehicles as the driver drives with caution.
Therefore, in this study, five sections where an inflection point occurred in the speed - flow rate graph and a certain LOS(Level Of Service) were selected and analyzed among the sections where the section enforcement system installed on the domestic one-way two-lane highway was installed.
In order to calculate the maximum traffic flow rate at the point in time of the ASE, the traffic volume is collected for 15 minutes using the VDS (vehicle detection system) near the point at which point enforcement is taking place in the ASE system and AVC (automatic vehicle classification) is used to calculate the maximum traffic flow rate.
The ratio of each vehicle type was derived, and the maximum traffic flow rate before and after the installation of the ASE system was calculated by calculating the heavy vehicle correction coefficient.
These calculated values were confirmed using a statistical test method (t-test).
As a result of the analysis, the ratio of heavy vehicles is high, and there is a difference in the maximum traffic flow rate in the hilly section regardless of the speed limit.
However, it was found that the ratio of heavy vehicles was low and there was no difference in the maximum traffic flow rate in the flat and downhill sections.
In addition, it was analyzed that the critical speed also decreased in the section where the maximum traffic flow rate decreased.