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This research evaluates the performance of non-intrusive detection technologies (NITs) for traffic signals in Minnesota. Prior work shows that while no single NIT device performs best in all situations, under specific circumstances, some NIT devices consistently outperform others. Our goal in this research is to find which NIT devices perform better in conditions specific to Minnesota and provide cost estimations and maintenance recommendations for operating these devices year-round. Our research has two main components: 1)synthesizing national and local experiences procuring, deploying, and maintaining NITs, and 2) evaluating real-world NIT deployments in Minnesota across different weather conditions. Our results and analysis combine the results from these steps to make recommendations informed by research and real-world experience operating NIT devices. Through interviews with Minnesota traffic signal operators, the research finds that environmental factors like wind, snow, and rain cause most NIT failures, requiring costly on-site maintenance. Operators emphasize the need for central monitoring systems, sun shields, and heated lenses to maintain performance. The research then analyzes NIT video, signal actuation, and weather data at six Twin Cities intersections using Iteris and Autoscope Vision technologies. No single NIT performs best, aligning with previous findings, but Autoscope Vision is less prone to lens blockages requiring on-site service. Our analysis also finds some intersections have more failures, indicating location and geometry impact performance. Key recommendations are based on the relative performance of a NIT in different weather conditions and accounting for local weather conditions when selecting a NIT at an intersection. We also recommend using central monitoring systems to troubleshoot remotely, installing heat shields to prevent snow/rain accumulation, and routine annual checks and checks after major storms.

Ramp metering is one way to address freeway traffic congestion. This study employs the Traffic Management Laboratory (TRAMLAB) to evaluate the effectiveness of Minnesota Department of Transportation's control strategy in three Twin Cities freeway sections totaling approximately 65 miles. It develops a new traffic management concept for early detection of incident-prone traffic conditions and integrates it in order to smooth flow and prevent incident occurrence, thereby further reducing delays and improving safety. The project is part of a larger program which aims to develop the TRAMLAB as part of the ITS Laboratory at the University of Minnesota. Such an environment will contain state-of-the-art traffic simulation programs and allow the development of viable, intelligent, and automated traffic-flow simulation programs and simulation systems that can function as both operational and research tools.

A new ramp metering strategy implemented on the Twin Cities freeway system to reduce ramp waiting times was evaluated through microsimulation of freeway activity. The study compared Stratified Ramp Metering strategy with the previous Zone Metering Strategy and with no control strategy. Comparison with Zone, which was designed to favor freeway flow, showed the new strategy succeeded in greatly reducing ramp delays and lines. When compared to the results of no control strategy, it reduces freeway travel time, increases freeway speed, smoothes the flow of traffic, and reduces the number of stops. However, travel time, fuel consumption and pollutant emissions are unpredictable under the newer system. Compared to no control strategy, such measures of effectiveness may improve or worsen depending on the freeway patterns and demand. Based on these findings, the researchers will seek improvements to the design of the Stratified Ramp Metering algorithm so as to factor in disruptive traffic patterns.

Comprehensive methodologies are proposed for improving the quality of both freeway and arterial intersections traffic volumes for the purpose of enabling and improving traffic simulations. Specifically, established and enhanced procedures for checking and correcting freeway temporal errors are integrated with an optimizationbased algorithm for reconciling spatial inconsistencies in freeway traffic counts. In addition to this, an empirical methodology is further integrated to balance arterial intersection traffic counts. The proposed methodologies have been successfully automated and implemented as two computer programs, i.e., TradaX for processing freeway volume and ArtBaT for arterial intersection traffic counts. Initial evaluations of these tools suggest that they have the potential of reducing total modeling time by 25% ~ 30%, while resulting in improved calibration of simulation models, more reliable analysis, and better use of staff resources for meeting project deadlines.

This report presents a study of the impact lane markings and signing have on driving behavior at a two-lane roundabout located in Richfield, Minnesota. After its completion in 2008, this roundabout sustained a suspiciously high amount of crashes. In response, through this study, engineers experimented with changes in the roundabout's signs and lane markings, as roundabout design regulations are relatively lax and nonspecific in contrast to those for standard signalized intersections. An observational study was conducted that reduced 216 hours of before and after video records of the roundabout into a database of all the violations committed by drivers. Along with the observational data, crash records were analyzed and demonstrated that improper turns and failing to properly yield account for the majority of collisions. The changes implemented in the approaches to the roundabout and specifically the extension of the solid line seems to have reinforced the message to the drivers that they must select the correct lane before approaching the roundabout entrance. Although choosing the correct lane does not directly address yielding violations, it does reduce the occurrence of drivers conducting an improper turn and to some extent reduces the need for a driver to change lanes within the roundabout. The implemented changes produced a 48% reduction in normalized occurrences of improper turns, and a 53% reduction in normalized occurrences of drivers choosing the incorrect lane a month after the changes, while a year later, these reductions were 44% and 50%, respectively.

The Twin Cities freeway network is a densely instrumented and growing transportation system. As the Minnesota Department of Transportation (MnDOT) pursues a performance-based management strategy to monitor the health of the network and make planning and management decisions, the data from this vast network is being examined using a variety of methods. To provide MnDOT with timely performance information regarding the Twin Cities freeway network, a streamlined program was developed based on existing and new methodologies. The Highway Automated Reporting Tool (HART) utilizes a user-friendly interface for corridor, date, time, and report selection. Selected data are automatically examined to identify and correct errors and produce 'cleaned' data for use within each report. Using interpolation and autoregressive integrated moving average (ARIMA) techniques, small errors are corrected in place while preserving as much useful data as possible. Larger issues are corrected using an imputation algorithm relies on uses nearby sensors and historical data to create representative replacement data. In this first version of HART, four reports are included: Speed-Based Congestion, Congestion Intensity, Lost and Available Capacity, and Maximum and Total Throughput. The Speed-Based Congestion report matches the existing methodology used to generate the annual Congestion Report.

Active Traffic Management (ATM) strategies are being deployed in major cities worldwide to deal with pervasive system congestion and safety concerns. While such strategies include a diverse array of components, in the Twin Cities metropolitan area the deployment of the Intelligent Lane Control Signs (ILCS) allowed for the implementation of Variable Speed Limits (VSL). The VSL system in the Twin Cities aims to detect congestion and preemptively warn upstream drivers to reduce speed. By reducing the severe change in speed between upstream and downstream traffic, safety and operational benefits are sought. This report presents an investigation of the effect the I-94 VSL system has on the safety of the high frequency crash area located on the westbound lanes of the freeway through downtown Minneapolis (I-94/I-35W commons). This report describes several methodologies that were used to examine the impact of the VSL system within the I-94/I-35W commons high crash area. Numerous data sources were utilized, including video records of crash and near crash events, loop detector traffic measurements, machine vision sensor data, and actuations from the VSL system. A before-after approach was taken to examine the incident rates for crashes and near crashes using visually identified events within video data. Utilizing the unique capabilities of the Minnesota Traffic Observatory's I-94 Freeway Lab, high resolution traffic measurements, collected by machine vision sensors at the bottleneck location, were used within a new cross-correlation based analysis methodology to measure and visualize shockwave activity before and after the implementation of the VSL system.

Dynamically priced High Occupancy Toll (HOT) lanes have been recently added to the traffic operations arsenal in an attempt to preserve infrastructure investment in the future by maintaining a control on demand. This study focuses on the operational and design features of HOT lanes. HOT lanes' mobility and safety are contingent on the design of zones ("gates") that drivers use to merge in or out of the facility. Existing methodologies for the design of access zones are limited to engineering judgment or studies that take into consideration undersized amount of observations. Case in point is the fact that the design philosophes between the two HOT facilities in Minnesota are diametrically opposed. Specifically, the I-394 freeway, the first dynamically priced HOT lane, was designed with a closed access philosophy, meaning that for the greater length of the roadway access to the HOT lane is restricted with only specific short-length sections where access is allowed. In contrast I-35W, the second HOT corridor, was designed with an open access philosophy where lane changes between the HOT and the GPLs are allowed everywhere except for a few specific locations. This contradiction generated questions as to effect each case has on safety and mobility. This study presents an assessment of safety and mobility on the two facilities as they operate today and highlights the issues present on either design.

Long-term, regional travel demand models are essential tools used by planning organizations for resource management, project scheduling, and impact studies. Developed primarily at the macroscopic level, these tools lack sufficient detail to capture the influence of local geometry, dynamic traffic controls, or advanced transportation demand management (ATDM) strategies. To bridge the gap, a hybrid mesoscopic-microscopic model was developed. The core of the model, surrounding two light rail corridors in Minneapolis-Saint Paul, Minnesota, was developed at high resolution for microscopic simulation to capture the interaction between traffic signals, transit systems, and the road network. The remainder of the greater Twin Cities area was implemented based on the Regional Planning Model (RPM) maintained by the Metropolitan Council. Interfacing the Aimsun-based hybrid model with the Cube-based RPM, the Twin Cities Metro Hybrid Simulation was used to iteratively improve mode choice and traffic assignment to achieve a dynamic user equilibrium state. Important lessons were learned regarding the effort required to develop and maintain such a model with implications for future large scale regional modelling.

While High Occupancy Vehicle (HOV) lanes have been used for decades as a strategy for mitigating congestion, research has shown that they are not always effective. A 2001 study of the I-394 and I-35W HOV lanes in Minnesota found that the HOV lanes were on average underutilized, moving fewer people than the General-Purpose Lanes (GPL) even with the increased number of passengers per vehicle. To address the issue of underuse, in 2003 the Minnesota Legislature authorized the conversion of the I-394 HOV lanes into High-Occupancy Toll (HOT) lanes, named the MnPASS Express Lanes. The MnPASS lanes operate using a fully dynamic pricing schedule, where pricing is dictated by the level of congestion in the HOT lane. To better understand the nature of HOT lanes and the decisions of their users, this study explored the possibilities for a microscopic traffic simulation-based model of HOT lanes. Based on a series of field studies where the price of the toll was changed while observing changes in demand in the HOT lane, models describing the lane choice behavior of MnPASS users were developed and calibrated. These models interfaced with the traffic simulation software Aimsun through a number of extension modules and tested on the two MnPASS corridors of I-394 and I35W corridors in the west and south suburbs of Minneapolis, Minnesota. The integrated HOT simulation tool was also used to develop and test a number of alternative pricing strategies including a more efficient version of the current strategy.