AIMSUN Plug-Ins
Wuping Xin 2007 (c)
Freeway ramp metering in the Twin Cities metro area goes back as early as 1969, when the Minnesota Department of Transportation (Mn/DOT) first tested ramp metering in the I-35E pilot project. Following this Mn/DOT developed a coordinated traffic responsive rampcontrol strategy called ZONE metering algorithm, and successfully implemented it in the Minneapolis/St. Paul metropolitan area to smooth traffic flow at merging areas and minimize bottleneck congestion. Even though the ZONE metering strategy has been continuously improved since its inception, its control objective did not change essentially over the years. This objective focused upon maximizing freeway traffic throughput at bottleneck locations, sometimes at the expense of delays at entrance ramps. As ramp queues and wait times multiplied with the rising demand during the 1990s’, public skepticism on the effectiveness of ramp control mounted, finally leading to an 8-week shutdown study in late 2000. The findings from the shutdown study confirmed the overall benefits of ramp metering; at the same time, also substantiated the public concerns of excessive ramp wait times and highlighted the need for modifications toward an efficient but more equitable ramp control strategy. Following this, Mn/DOT modified the control objective and developed a new ramp control strategy called Stratified Zone Metering which seeks to balance the efficiency of the traditional ramp control with the new requirement of managing ramp wait times.
Implementation of the new strategy in the Twin Cities freeway system started in early 2002; however, its full deployment was not completed until 2003.
Implementation of the new strategy in the Twin Cities freeway system started in early 2002; however, its full deployment was not completed until 2003.
In order for comprehensive evaluation of the new Stratified Zone Metering using micro-simulaiton tool, two AIMSUN plug-ins were developed for emulating the previous ZONE control algorithm and the new SZM at the University of Minnesota.
These two plug-ins have been used to evalute, optimize and improve the SZM in various ramp metering related projects.
These two plug-ins have been used to evalute, optimize and improve the SZM in various ramp metering related projects.
AIMSUN Remote Control Application
Proprietary Development at KLD Associates,Inc.
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AIMSUN communicates with the server via Socket.
