2013 Session: 547

• Evaluation and Development of Vehicle-Type-Specific Acceleration Models
  Abstract: This paper uses collected real-world data to evaluate the performance of vehicle acceleration models for different types of vehicles. Real-time data collection is made by vehicles equipped with GPS units. Three vehicle types, passenger cars (PC), passenger trucks (PT), and combination trucks (CT) are considered in the study. The performance of several existing acceleration models are first evaluated through the investigations of the goodness of fit using residual plots and the sum of square (SSE) measure. After significant deficiencies of these models are identified, a new model form is proposed. The new model represents a better fit to the acceleration profiles of the collected data. The study also concluded that different model parameters are needed for different types of vehicles as they have different acceleration characteristics.
  Authors: Gu, Caoyi; Zhang, Yunlong; Zhang, Li
  Authors: Gu, Caoyi; Zhang, Yunlong; Zhang, Li
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-4535
• Using Eye Movements to Evaluate the Effect of Total Awake Time on Attention Maintenance and Hazard Anticipation in a Driving Simulator
  Abstract: Driving while sleepy or drowsy are leading contributors to road crashes. Sleepiness and drowsiness usually occur at the end of a prolonged period of time during which an individual has been awake. Although these factors have been heavily researched, it is not clear how one of their primary causes, a prolonged total awake time (TAT), might affect driving skills such as attention maintenance and hazard anticipation, two skills that are crucial for safe driving. This study investigated how these two driving skills are affected by prolonged TAT, and if so to what extent. Eighteen experienced drivers completed two driving simulator evaluation sessions: pre-test and post-test. For all participants, the pre-test occurred during the morning hours approximately one hour after waking up. For six drivers the post-test occurred in the morning (Short-TAT group), for six after lunch (Lunch group; effect of post lunch dip group), and for six early in the evening (Long-TAT group). In each session, participants were asked to navigate a simulated world that included eight scenarios: four examined drivers’ attention maintenance abilities and four examined their hazard anticipation skills. While driving, all participants’ eye behaviors were measured. The results showed that Long-TAT drivers’ attention maintenance and hazard anticipation skills were compromised. Possible implications for road safety are then discussed.
  Authors: Hamid, Malek; Borowsky, Avinoam; Divekar, Gautam; Fisher, Donald L.
  Authors: Hamid, Malek; Borowsky, Avinoam; Divekar, Gautam; Fisher, Donald L.
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-4232
• Simulator Study of Effects of Windmill Power Source on Drivers at Signalized Intersection
  Abstract: This simulator-based research examines the effects of a windmill power source at the signalized intersection on drivers in terms of visual fixation, heart rates and perception-reaction time. A linear regression model is developed to test if the windmill distracts drivers’ eye fixation and indicates an increase on off-road glance duration resulting from the windmill. In addition, the seemingly unrelated regression model is applied to study the impact on drivers’ psychological reaction measured by heart rate. The increase of the mean and the standard deviation of heart rates indicate that the existence of windmill does increase drivers’ stress level on average. Perception-reaction time is tested as one indicator of driver performance and the coefficient estimated for linear regression is not significant for the windmill indicator. That is, although the windmill affects drivers’ eye fixation and psychological feeling, it does not show the significant effect on driving performance measured as perception-reaction time at onset of green signals with statistical significance.
  Authors: Li, Wei; Wu, Zifeng; Sharma, Anuj; Gyawali, Sunil
  Authors: Li, Wei; Wu, Zifeng; Sharma, Anuj; Gyawali, Sunil
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-4962
• Estimating Critical Gap: Comparison of MethodologiesUsing Robust, Real-World Data Set
  Abstract: Understanding the gap acceptance behavior of drivers is critical to transportation professionals dealing with roadway design and safety. Inaccurate information on how drivers utilize gaps in traffic can lead to inappropriate and potentially dangerous design decisions. Arguably, the best mechanism for understanding this behavior is through field investigations; however, little uniformity exists regarding best practices for analyzing gap acceptance field data.A number of different methodologies have been proposed and are currently in use for analyzing gap acceptance data. Subsequently, the question that arises is whether the analysis method chosen affects the results of the analysis. Previous works have made comparisons of different analysis methods, but with the intent of demonstrating the superiority of the author’s new analysis method. The research conducted herein is focused on a direct, and objective comparison of existing methodologies.More specifically, this paper uses observations from a large-scale-field study of 2,700 drivers, and presents a comparison of the five most commonly employed methods with two variations of each for a total of ten unique gap analysis methods. The lone criteria for each analysis method considered was that it have a firm fundamental base and be computationally simple enough for everyday application. The ease of implementation, sample size requirements, and results of each method are discussed.Methods used for analysis resulted in significantly different results. This raises concerns when comparing studies using different analysis methodologies. In addition, critical gap estimates from the evaluated methodologies were compared with the widely accepted values of the Highway Capacity Manual.
  Authors: Tupper, Steven; Knodler, Michael A.; Fitzpatrick, Cole D.; Hurwitz, David S.
  Authors: Tupper, Steven; Knodler, Michael A.; Fitzpatrick, Cole D.; Hurwitz, David S.
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-5019
• Analysis of Drivers' Stop-or-Run Behavior at Signalized Intersections Using High-Resolution Traffic and Signal Event Data
  Abstract: Intersection safety is a national priority, and a driver¡¯s stop-or-run decision at signalized intersections is an important factor that leads to red-light running and causes intersection-relatedaccidents. This paper investigates this important issue using high-resolution traffic and signal event data collected from loop detectors.The paper first develops a simple method to identify first-to-stop, yellow-light running, and red-light running cases using the information from both stop-bar detectors located right behind the stop-line and advance detectors located several hundred feet upstream from the stop-line. The traffic data collected from advance detectors (including occupancy time and time gap),signal information collected from the signal system (including used yellow time and the left time to yellow start),the information from three preceding vehicles, and the information from vehicles on adjacent lanes are all applied to identify the factors that significantly impact drivers¡¯ decision making. A binary logistical regression method is applied to analyze the significance of all these factors. From the investigation results, we found out that occupancy time, time gap, used yellow time, time left to yellow start, time gap between the first two preceding vehicles, whether the nearest preceding vehicle runs through intersection during yellow, and whether there is a vehicle passing through the intersection on the adjacent lane show a significant impact on drivers¡¯ decisions. A prediction model, which predicts if a driver stops or runs through intersection, is also developed using the information collected by advance detectors. The testing experiment shows the accuracy of the model is as high as 87%. This research shows the possibility of using loop detector data to predict drivers¡¯ stop-or-run decisions in real time. This work could be tremendously beneficial for signalized intersection safety improvement especially for the development of real-time intersection collision avoidance or intelligent intersection decision support systems.
  Authors: Wu, Xinkai; Liu, Henry X.; Cheng, Wen
  Authors: Wu, Xinkai; Liu, Henry X.; Cheng, Wen
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-5050
• Oppel-Kundt Illusion and Lateral Optic Flow Manipulation in Affecting Perceived Speed in Approaching Roundabout: Experiments with a Driving Simulator
  Abstract: Resolution A/RES/64/255 of the United Nations General Assembly proclaimed the period 2011–2020 as the “Decade of Action for Road Safety” worldwide, with the goal of stabilizing and then reducing the forecast level of road traffic fatalities around the world by increasing activities conducted at national, regional and global levels. Looking at the facts concerning road safety, as stated by the UN, one of the most important problems is vehicle speed.The aim of this work is to evaluate the potential influence of traffic-calming measures on drivers' speed. In particular, attention focuses on very simple, low-cost perceptual measures based on the Oppel-Kundt illusion and lateral optic flow manipulation.A driving simulator experiment was used to analyse three countermeasures, located along the approach to a roundabout in a rural area, against the control condition (no countermeasures, corresponding to the current configuration of the roundabout in question): evenly spaced guide posts, unevenly spaced guide posts, and optical speed bars.Results showed that both evenly and unevenly spaced guide posts significantly reduced drivers' speed with respect to the control condition. Mean speed reduction, measured between the entry and exit points of the analysed segment, was approximately 4.2%, which was significant in terms of reduction of risk. No difference was found between the treatments called ‘constant guide posts’ and ‘wide-to-thin guide posts’. The potential for reducing drivers' speed was only moderate in the case of optical speed bars.From the practical point of view, the proposed measures have the additional advantages of being easy to implement and not requiring regular maintenance, compared with other common measures based on pavement marking.
  Authors: Rossi, Riccardo; Gastaldi, Massimiliano; Biondi, Francesco; Mulatti, Claudio
  Authors: Rossi, Riccardo; Gastaldi, Massimiliano; Biondi, Francesco; Mulatti, Claudio
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-5329
• Evaluating Alignment Consistency for Mountainous Expressway in Design Stage: Driving Simulator-Based Approach
  Abstract: Evaluating design consistency is of great significance for safety evaluation on roadway design prior to its construction. Conventional design consistency showed little consideration of driving performance due to the limitation in data availability. More importantly, they were performed only on the existing roads. In this study, a simulated driving experiment was carried out in a high-fidelity driving simulator in Tongji University (Shanghai). A design stage four-lane (two-ways) mountainous expressway was implemented geo-based on the basis of the detailed road design blueprint. We attempted to establish a practical approach for evaluating its design consistency through investigating operating speed consistency, vehicle stability and vehicle lateral offset (vehicle trajectory). Specifically, the speed consistency is studied using the classic indicators ¨C the 85th speed reduction and 85th maximum speed reduction. The vehicle stability was evaluated using lateral acceleration, rollover coefficient and the conventional side-friction parameter. In the lateral offset analysis, the adjusted lateral offset was newly proposed, which is defined as the lateral offset from ideal vehicle trajectory. Utilizing the adjusted lateral offset can reflect the trajectory variation dependent on the characteristics of road geometry, which leads to the discovery of the inconsistencies in the studied mountainous expressway. The lateral acceleration and rollover coefficient could be considered as supplementary measures to provide insights into drivers¡¯ comfortableness as well as the rollover risk. Another contribution of this work is that we developed predicting models for the considered consistency measures. The purpose is to better understand the relationship between driving performance and roadway geometry characteristics, as well as to provide a practical formulation in a rigorous manner for road design consistency evaluation.
  Authors: Wu, Xingwei; Wang, Xuesong; Lin, Hangfei; He, Yefei; Yang, Le
  Authors: Wu, Xingwei; Wang, Xuesong; Lin, Hangfei; He, Yefei; Yang, Le
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-2309
  Practice-Ready: Yes
• A Flexible, Mobile Video Camera System and Open Source Video Analysis Software for Road Safety and Behavioural Analysis
  Abstract: This paper presents a scalable, discreet and mobile video-camera system that takes elevated video data of roadway locations for traffic safety analysis. The video is used to extract microscopic traffic parameters including road-user trajectories, lane changes and speeds. Collected video data is processed using an open-source automatic tracking tool. Trajectories can be then used to analyse road user behaviour for specific locations (intersections or highway sections) or to evaluate the safety effectiveness of a treatment. The different elements of the systems including data collection and processing are discussed. To illustrate its versatility, different applications (case studies) illustrate the use of the video-camera system and open-source video-tracking and analysis tool. This includes video-based conflict analysis at highway ramps and behavioural analysis of pedestrians and cyclists at signalized intersections, including red-light violations.
  Authors: Jackson, Stewart; Miranda-Moreno, Luis Fernando; St-Aubin, Paul; Saunier, Nicolas
  Authors: Jackson, Stewart; Miranda-Moreno, Luis Fernando; St-Aubin, Paul; Saunier, Nicolas
  Year: 2013
  Document Type: Paper
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-3229
  Practice-Ready: Yes
• A Flexible, Mobile Video Camera System and Open Source Video Analysis Software for Road Safety and Behavioural Analysis
  Authors: Jackson, Stewart
  Authors: Jackson, Stewart
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-3229
• Simulator Study of Effects of Windmill Power Source on Drivers at Signalized Intersection
  Authors: Li, Wei
  Authors: Li, Wei
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-4962
• Estimating Critical Gap: Comparison of Methodologies Using Robust, Real-World Data Set
  Authors: Tupper, Steven
  Authors: Tupper, Steven
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-5019
• Evaluating Alignment Consistency for Mountainous Expressway in Design Stage: Driving Simulator-Based Approach
  Authors: Wang, Xuesong
  Authors: Wang, Xuesong
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Safety and Human Factors
  Session: 547
  Paper Number: 13-2309