Vendor Comparison of Video Detection Systems

Video detection has become increasingly popular for presence detection at signalized intersections because of its versatility. However, several reports have documented performance problems in specific systems. This paper quantifies the performance of three different commercially available video detection systems. The systems were tested in May and September 2005 for presence detection accuracy. Prior to the May 2005 test, a representative from each vendor configured the video detection zones to match the loop detection zone as closely as possible. The outputs from the loop detection for the through-right and left-turn lane groups were compared with the corresponding output from each of the video detection systems. Whenever there was a discrepancy between the loop and video, a digital video was observed to determine the cause of the discrepancy. Missed calls and false calls were categorized for each system. The errors were also categorized according to the impact that they would have on signal operations. During a 24hr test on two separate days, the number of missed detections longer than 5 seconds ranged from 9 to 147, and the number of false calls longer than 5 seconds ranged from 16 to 149

Active Transportation Research at Northern Arizona University

Dr. Smaglik is currently working on three separate transportation research projects at Northern Arizona University. This talk will touch briefly on each of the three projects, the concepts behind them, workplans, and expected deliverables. The projects include work with the Oregon DOT on the impact of less than optimal vehicle detection on adaptive control algorithms, development of a ped priority algorithm through a NITC project (as a Portland State subcontractor), and internally funded work on a power harvesting traffic sensor.https://pdxscholar.library.pdx.edu/trec_seminar/1087/thumbnail.jp

Use of Decision Assistance Curves in Advanced Warrant Analysis for Indirect Left-Turn Intersections

This paper develops decision assistance curves (DAC) to compare delay-based performance measures for three indirect left turn (ILT) intersections, namely median U-turn (MUT), continuous flow intersection (CFI), and jughandle, relative to a conventional signalized intersection. The DACs consist of two graphical tools: (i) DAC-classifier and (ii) two sets of DAC-contours. DAC-classifier plots are used to select the intersection type that produces the minimum system average delay for a specified main and cross-street volume configuration. DAC-contour plots are used to estimate the system average delay difference between a chosen ILT and a conventional signalized intersection as well as to estimate the increase in average delay as compared to a conventional signalized intersection for the most negatively impacted movement. These tools can be used by planners, engineers, or other decision makers to visually identify the intersection type that provides the least average system delay under given volume conditions as well as estimated tradeoffs for choosing a specific intersection type. It was found that the conventional signalized intersection, with protected left turns, was never optimal under studied scenarios. This implies that, for all the studied conditions, there exists at least one ILT or permitted left turn alternative that produces lower delay than the conventional signalized intersection

Assessing the Impact of Three Intersection Treatments in a Bicycling Simulator

Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With cyclist injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research has addressed crash causality and helped to develop several roadway treatments to improve bicyclist safety, but little has been done to compare and contrast the benefits of the various treatment types. This bicycling simulator study examined the impacts of three different intersection treatments (i.e., bike box, mixing zone, and bicycle signals) to better understand their influence on bicyclists\u27 comfort, levels of stress, and riding behaviors. This improved understanding allowed researchers to make recommendations for which of the three designs proved to be most effective for reducing the risk of vehicle-bicycle collisions at signalized intersections. Forty participants successfully completed the study by responding to twenty-four scenarios while riding in the Oregon State University Bicycling Simulator. Time-space measurements revealed that the mixing zone treatment correlated with the most unpredictable riding behaviors. Analysis of the participants\u27 eye-movements revealed a lower rate of recognizing the conflict vehicle when traversing the bicycle signal treatments. Galvanic Skin Response measurements were used to measure participants stress levels but found no statistically significant results, although it was found that the mixing zone elicited slightly larger stress responses. Researchers found the bike box design to be the most versatile, providing a balance of increased safety while also requiring the participant to perceive potential danger and be ready to respond accordingly. The results of this research can provide a better understanding of how to best implement these intersection treatments to increase bicyclists\u27 safety at signalized intersections

Leading Pedestrian Interval Implementation as a Marginal Costs and Benefits Problem

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPI) to provide pedestrians with a walk signal for a few seconds prior to the parallel vehicular green indication. Previous research using before-after studies and simple economic analyses shows that LIPs are low cost tools that can reduce vehicle-pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, there is a little guidance for municipalities on when to implement LPIs. this paper develops a marginal costs and benefits framework using quantitative metrics, extending the concept of traffic conflicts and marginal safety-delay tradeoffs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The guidance provided by this method helps quantify the probability of a conflict happening, and provides direction on whether or not to implement an LPI at a given location based upon macroscopic level inputs, including turning movement counts, crash data, and geometry. A case study with sample data indicates that an LIP is cost effective for the scenario presented

Managing User Delay with a Focus on Pedestrian Operations

Across the United States, walking trips are increasing. However, pedestrians still face significantly higher delays than motor vehicles at signalized intersections because of the traditional signal timing practices of prioritizing vehicular movements. This study explored methods to reduce pedestrian delay through the development of a pedestrian priority algorithm that selects an operational plan favorable to pedestrian service, provided a user-defined volume threshold has been met for the major street. This algorithm—along with several operational scenarios—was analyzed with Vissim with the use of software-in-the-loop simulation to determine the impact these strategies have on user delays. One of the operational scenarios examined was that of actuating a portion of the coordinated phase, or actuated–coordinated operation. Following a discussion on platoon dispersion and the application of it in the design of actuated–coordinated signal timing parameters, a sensitivity analysis was performed on vehicle extension timers to explore the impact that this coordinated movement parameter has on user delay. In the scenario analysis, it was shown that employing fully actuated (also known as free) operation—either with the designed algorithm or without—was an effective method of reducing pedestrian delay on the minor street while decreasing average intersection vehicle delay for the volumes used in the simulation. The vehicle extension sensitivity analysis showed that shortening the extension timer of an actuated–coordinated phase can reduce pedestrian delay on the minor street without increasing overall vehicle delay. This tool could be used by agencies during coordinated operation to prioritize pedestrians

Evaluation of Sidewalk Autonomous Delivery Robot Interactions with Pedestrians and Bicyclists [Research Brief]

69A3551747109Information and communication technology advancements and an increased demand for contactless deliveries following the Covid-19 pandemic outbreak resulted in the growing adoption of automated delivery services. In this research project, we examine the impacts that sidewalk autonomous delivery robots (SADRs) have on the objective safety and perceived comfort of pedestrians and bicyclists who share pathways with this last-mile food delivery service that has been deployed on college campuses