SRF Consulting Group

This study evaluates recent technology that uses inductive loop detectors, traditionally used for collecting traffic volume and speed data, to provide vehicle classification data by examining the high-resolution signature produced when a vehicle passes over the sensor. The project aims to verify the accuracy of the new classification system, collect additional heavy vehicle data to help improve system accuracy, and familiarize MnDOT staff with the technology through training and the development of a field deployment manual. Through collaboration with MnDOT and the technology vendor CLR Analytics, Inc., the VSign vehicle classification system has been installed at five sites in Minnesota with preexisting loop detection systems. The final sites are representative of MnDOT facilities, feature a mix of heavy vehicle traffic, and provide accessibility for deployment staff. Data from the VSign system was compared with manually verified ground-truth data collected from video under both the Federal Highway Administration (FHWA) and Highway Performance Monitoring System (HPMS) classification schemes. The system demonstrated high accuracy for passenger vehicles but varying accuracy for different classes of heavy vehicles, though performance improved under the HPMS classification scheme. The VSign system was also evaluated against the video-based iTHEIA™ system at one site, which VSign outperformed in both classification accuracy and detection rate. The results suggested that the VSign system was more effective at locations where vehicles maintained consistent speeds and were centered in the lane due to the negative effects of variations in speed and lateral position on the consistency of vehicle signatures read by the detector.

This report summarizes the approach, findings, and recommendations of the Minnesota Truck Size and Weight (TS&W) Project led by the Minnesota Department of Transportation (Mn/DOT) in cooperation with other public and private stakeholders. The purpose of the project is to assess changes to Minnesota's TS&W laws that would benefit the Minnesota economy while protecting roadway infrastructure and safety.

This report documents the activities and results of a 2-year test of non-intrusive traffic detection technologies. Non-intrusive technologies are defined as data collection methods that can be done without intruding into the roadway for installation. Non-intrusive devices have the advantage of not disrupting traffic flow or exposing field personnel to dangerous conditions. While there is potential for new technologies to replace the traditional methods of data collection, such as inductive loop detectors and road tubes, there are many questions regarding their performance. This report provides practitioners with useful information about the performance of non-intrusive technologies and specific devices within each technology. Seventeen devices representing eight different technologies were evaluated in varying environmental and traffic conditions. The following technologies were tested: passive infrared, active infrared, magnetic, radar, doppler microwave, pulse ultrasonic, passive acoustic, and video. Testing was done at both freeway and intersection locations. Emphasis was placed on urban traffic conditions, such as heavy congestion, and locations that typify temporary counting locations, such as 48-hour or peak hour counts. The evaluation also focused on the ease of system setup and use, general system reliability, and system flexibility.

This report identifies the installation experiences, challenges encountered, and lessons learned for two types of radio interconnect systems implemented within the Twin Cities metropolitan area. Radio interconnect was found to be a viable and worthwhile communication technology that can be successfully and effectively implemented and operated.

The majority of traffic detection technology and sensor research has focused on the detection of "motorized" traffic. This has left a need for objective information on the performance of "non-motorized' traffic detectors. Bicycles and pedestrians are the two most common types of non-motorized traffic. In recent years, sensors have been developed to detect the presence of pedestrians and the speed and presence of bicycles. This has been accomplished with a variety of technologies, including microwave, infrared, video and inductive loops. With the development of ITS applications, automated pedestrian detectors are beginning to compliment the existing pushbutton detectors. These applications optimize intersection operations and improve safety by reducing the conflicts between vehicles and pedestrians. Similarly, bicycle detectors are being used to provide detection inputs to traffic signals for call and extend functions. These technologies are also a valuable tool in gathering historic data. This report documents the current state of pedestrian and bicycle detection and presents evaluation results from a field test conducted of six different bicycle/pedestrian sensors.

Concern about traffic congestion and loss of mobility on our highways and interstates led Mn/DOT to conduct an Interregional Corridor Study, completed in October 1999. The goal of the Study is to proactively manage the important connections between regional centers in a more cost-effective manner. This goal is consistent with Mn/DOT's strategic objective to develop an interregional corridor system that enhances the economic vitality of the state by providing safe, timely, and efficient movement of people and goods to regional trade centers.

While the 1997 Statewide Transportation Plan supports investments that enhance safety and timely travel between activity centers (regional trade centers), it defined the Interregional Corridor System as the entire 5,200-mile principal arterial system. The entire principal arterial system is too large as the interregional system to allow sufficient focus on the key transportation corridors throughout the state. In addition, previous Plans did not provide guidance on how these corridors should perform from a mobility perspective. The result has been a lack of attention on some major corridors and some inconsistencies between districts on how corridors are managed. As a result, the Minnesota Department of Transportation (Mn/DOT) initiated the Interregional Corridor Study to identify important economic corridors in the state. The goal of the Interregional Corridor System is to maintain safe, timely and efficient transportation services between regional centers. Providing good transportation service to the main activity centers will improve or maintain productivity, reduce transportation costs and support the interdependencies that exist between different areas of the state and between Minnesota and other states and counties.

In 2000, the Minnesota Department of Transportation (Mn/DOT) identified and adopted a statewide system of arterial roadways that are critical to serving the economic interests of the state. This system, the Interregional Corridor (IRC) System, is comprised of two percent of the roadway miles in the state, but accounts for over 30 percent of the miles traveled. Over the past decade, many of the IRCs have been under increasing congestion and growth pressures. These pressures threaten the ability of Mn/DOT to deliver safe and efficient transportation services both now and in the future. To better address immediate needs and to plan for long-term transportation needs in the most threatened corridors, Mn/DOT developed seven Corridor Management Plans (CMPs). One of the corridors selected for a CMP was the 73-mile section of State Highway 169 from the 1-494 beltway to TH 60 south of Mankato.

The State Highway 169 study began by forming a broad-based Corridor Partnership, comprised of approximately 40 representatives from agencies and communities along the corridor. The Partnership was established to assist Mn/DOT in the development of the Corridor Plan, as well as to assist in ongoing corridor management and implementation. The Partnership had two working groups, a Technical Committee, whose role was to provide technical advice and direction to both Mn/DOT and the Policy Committee, and a Policy Committee, whose role was to review and advise Mn/DOT on major policy issues and corridor strategies. The process used in the development of the TH 169 Corridor Management Plan was intended to create a better understanding of the issues and concerns along the corridor, as well as to develop consensus with Corridor Partners for a long-term vision and action plan that will be implemented over time. The process was also intended to demonstrate how investments and decisions in one part of the corridor can significantly impact the overall performance of the entire corridor and, very importantly, the process emphasized the need for Corridor Partners to build relationships among the group in order to resolve common problems and support each other in realizing the corridor's vision.

This study on the adequacy of Freight Connectors to the Interregional and Major Highway System Study is another step in the development of information, tools and processes to improve freight planning and make better investment decisions in Minnesota. Previous efforts include the development of Mn/DOT’s Freight Facilities Database, the Statewide Freight Flow Study, and the Freight Planning Information Systems Requirements Analysis. The objective of these efforts is to make available to Mn/DOT Districts, planning agencies and the freight industry the resources for improving freight productivity and, ultimately, for increasing economic activity in the state. To accomplish this objective, it is important that Mn/DOT stay up-to-date with current, and anticipated freight issues by maintaining channels of communication open with the freight industry and stakeholders. In particular, Mn/DOT Districts are in a good position to dialogue with freight shippers and carriers in their region. In addition, Districts can take the results of these studies and share them with relevant freight stakeholders in their respective region.