Roadway System Assessment Using Bluetooth-Based Automatic Vehicle Identification Travel Time Data

This monograph is an exposition of several practice-ready methodologies for automatic vehicle identification (AVI) data collection systems. This includes considerations in the physical setup of the collection system as well as the interpretation of the data. An extended discussion is provided, with examples, demonstrating data techniques for converting the raw data into more concise metrics and views. Examples of statistical before-after tests are also provided. A series of case studies were presented that focus on various real-world applications, including the impact of winter weather on freeway operations, the economic benefit of traffic signal retiming, and the estimation of origin-destination matrices from travel time data. The technology used in this report is Bluetooth MAC address matching, but the concepts are extendible to other AVI data sources

A hazard-based analysis of airport security transit times

AbstractAirport security screening, and the amount of time it costs travelers, has been a persistent concern to travelers, airport authorities, and airlines – particularly in recent years where changes in perceived threats have resulted in changes in security procedures that have caused great uncertainty relating to security transit times. To gain a better understanding of the factors influencing travelers' security transit times, determinants of security transit times are studied by using anonymous Bluetooth media access control address matching to determine the actual security travel times of individual passengers at the Cincinnati/Northern Kentucky International Airport. These transit-time data are then analyzed using a random-parameters hazard-based duration model to statistically explore the factors that affect airport security transit times. The estimation results reveal, as expected, that a wide variety of factors affect security transit times including the number of enplaning seats (reflecting flight schedules), weather conditions, day of week, as well as obvious variables such as traveler volume and the number of open security lanes. The detailed statistical findings show that current security procedures are reactive instead of proactive, and that substantial reductions in security transit times could be attained by optimizing security operations using a statistical model such as the one estimated in this paper

High-Resolution Event-Based Data at Diamond Interchanges: Performance Measures and Optimizing Ring Displacement

This poster corresponds to the following article: Hainen, A.M., A.L. Stevens, R.S. Freije, C.M. Day, J.R. Sturdevant, and D.M. Bullock, “High-Resolution Event-Based Data at Diamond Interchanges: Performance Measures and Optimization of Ring Displacement,” Transportation Research Record: Journal of the Transportation Research Board, No. 2439, Transportation Research Board of the National Academies, Washington, D.C., pp. 12–26, October 2014. http://dx.doi.org/10.3141/2439-02 This article can be found here: http://docs.lib.purdue.edu/civeng/13

Leveraging High Resolution Signalized Intersection Data to Characterize Discharge Headway Distributions and Saturation Flow Rate Reliability

As highway systems become more congested, it becomes increasingly important to understand the reliability with which we can estimate important performance measures such as volume to capacity ratios, particularly as we move toward leveraging field infrastructure to obtain real-time performance measures. In 1947, Greenshields wrote a paper that characterized “green time consumed” by “car-in-line-number” that ultimately was called headway. Average headway is one of principles used by the highway capacity manual to estimate saturation flow rate at signalized intersections. However, the current analytical techniques calculate a deterministic value for saturation flow rate that does not consider the stochastic variation of saturation flow rate. This paper reviews techniques used to estimate saturation flow rate, and proposes enhanced calculation methods to group saturation flow rate estimates by queue length. Grouping saturation flow rate estimates by queue length provides a convenient framework to evaluate saturation flow rate reliability. The inter-quartile range (25% - 75%) of saturation flow rates was calculated to be 1000vph based on Greenshields’ calculation techniques. Using the proposed enhanced calculation characterizing saturation flow rate, the inter-quartile range of saturation flow rate was shown to decrease from approximately 400 vph with 5 cars in a queue to 300 vph with 10 cars in queue. Because saturation flow rate is a fundamental input to volume-to-capacity performance measures, characterizing the stochastic variation of saturation flow rates provides a basic input for assessing how reliably one can estimate important performance measures such as volume-to-capacity ratios, as well as other performance measures that build upon volume-to-capacity ratios

Travel Time Observations Using Bluetooth MAC Address Matching: A Case Study on the Rajiv Gandhi Roadway: Chennai, India

Bluetooth MAC Address matching has become a useful approach for determining travel times on corridors in the United States. In September 2013, an international collaborative study was performed using this technology along a busy urban corridor in Chennai, India. Two Purdue University graduate students traveled to Chennai, India to interact and understand the dynamics of exchanging knowledge and implementing technologies in different environments. The students worked with students from IIT Madras to determine the feasibility of Bluetooth probe vehicle technology along a typical Indian corridor. The study determined that it is feasible to expand Bluetooth use in India. Using the technology, the impact of weather, holiday and peak hour related traffic events were determined and evaluated. Of particular note were the relative high penetration of Bluetooth devices, and the exceptionally strong impact of precipitation on the heterogeneous traffic stream in Chennai, India

Sequence Optimization at Signalized Diamond Interchanges Using High-Resolution Event-Based Data

Signalized diamond interchanges are pairs of ramp intersections characterized by interlocked left turns and relatively close spacing. This paper describes a series of performance measures derived from high-resolution signal controller event data that can be used to optimize the internal phase sequence and offset to improve traffic flows within diamond interchanges and to assess the progression of the interior movements qualitatively and quantitatively. The new heuristic developed in this paper improves on traditional green band optimization techniques by incorporating actual demand profiles measured in the field. A field analysis was performed on a diamond interchange at I-69 and 96th Street in northwest Indianapolis, Indiana, where the existing sequence data were collected and used to model the alternative sequences to identify the optimal sequence. Interior operations were improved under the optimized settings: the percentage of vehicle arrivals on green increased by 19% during the 09:00-to-15:00 midday plan. Video observations were used to corroborate the data and are included in a video synthesis of the time–space trajectories. </jats:p