Carlos Sun

University of Missouri | Mizzou · Department of Civil and Environmental Engineering

Sleep disorders and various acute and chronic medical conditions affect the quality and quantity of an individual’s sleep causing excessive day time sleepiness. This study examined the relationship between clinical sleep disorders (i.e., shift work sleep disorder (SWSD), sleep apnea and insomnia) and crashes using naturalistic driving study data. U...

Car crashes can occur in a variety of ways. A common type of collision involving two vehicles is when one vehicle rear-ends another vehicle. This study describes a methodology to understand the braking judgments in rear-end safety-critical events, i.e., crashes and near-crashes, using naturalistic driving study (NDS) data collected as part of USDOT...

Identification of crash risk factors and enhancing safety at work zones is a major priority for transportation agencies. There is a critical need for collecting comprehensive data related to work zone safety. The naturalistic driving study (NDS) data offers a rare opportunity for a first-hand view of crashes and near-crashes (CNC) that occur in and...

There are various ways in which a transportation agency can approach safety prediction. One could calibrate the Highway Safety Manual (HSM) using adjustment factors by ranges of exposure variable, calibrate it using a function, or develop jurisdiction-specific models. Various tradeoffs are involved in deciding on which approach to undertake, includ...

The Highway Safety Manual (HSM) provides guidance and tools to conduct quantitative safety analysis. Crash prediction models are used to estimate the expected number of crashes per year, by facility type, severity, and crash type. There are two approaches for applying the HSM crash prediction methodology to local conditions: (1) calibration of mode...

What effect does work activity type have on traffic conditions in a work zone? This question has still not been answered satisfactorily in practice. Without knowing the true effect a work activity has on traffic, practitioners are forced to make assumptions while scheduling work. This paper attempts to answer this question by studying the traffic f...

The current Federal Aviation Administration’s (FAA) safety risk management (SRM) process in the United States involves mainly the use of qualitative risk measures. The development of accurate quantitative models could complement existing qualitative analysis. This paper discusses quantitative models in the form of airfield incursion models (AIM) to...

How safe are the ramp terminals of a diverging diamond interchange (DDI)? This paper answered this question using data from DDI sites in Missouri. First, crash prediction models for ramp terminals for different crash severities were developed. These models were then utilized in the Empirical Bayes (EB) evaluation of DDI ramp terminals. Due to incon...

At the airfield in hub airports, many activities occur that involve a range of participants, including various-size aircraft, ground vehicles, and workers. The safety management system is FAA's approach for systematically managing aviation safety. A major component of the safety management system is safety risk management (SRM), which entails analy...

The J-turn, also known as the restricted crossing U-turn and Superstreet, is an innovative geometric design that can improve intersection safety. Although this design has been in use in several states for many years, there is very little research-based guidance for several design parameters. A driving simulator study was conducted to analyze the pa...

Owing to the J-turn’s safety effectiveness, it has become a viable alternative to replace high-crash, two-way, stop-controlled intersections on high-speed expressways. National guidance on the design of J-turns on high-speed highways is limited. What is the safety effect of spacing between the intersection and the U-turn? Under what circumstances i...

Recent evidence has shown that the diverging diamond interchange (DDI) design improves the safety of the ramp terminals and the overall safety of the interchange. What is still not known is the safety effect that a DDI has on adjacent intersections and the speed-change lanes (SCLs) at freeway entrances and exits. This study addressed this void by e...

The past decade has seen increased public interest in sustainable transportation modes in the United States. However, there is a relative lack of guidance regarding standards and specifications for bicycle facilities compared with the highway mode. This project sought to address this deficiency through the investigation of alternative pavement mark...

Objective: Red light cameras (RLCs) have generated heated discussions over issues of safety effectiveness, revenue generation, and procedural due process. This study focuses on the safety evaluation of RLCs in Missouri, including the economic valuation of safety benefits. The publication of the national Highway Safety Manual (HSM; American Associa...

The effectiveness of variable ‘advisory’ speed limit (VASL) systems in congested urban work zones was investigated. Except for one publication, all previous studies focused on regulatory speed limit systems. This study used a comprehensive set of performance measures to investigate VASL effectiveness. Four congested work zones with lanes reduced fr...

Diverging diamond interchanges (DDIs) are increasingly popular because they provide improved traffic operations and cost savings. On the basis of theory, DDIs should be safer than conventional diamonds, but previous empirical safety studies have been limited. The objectives of this work were, therefore, to conduct a broader safety evaluation of DDI...

A site-specific analysis of the safety of diverging diamond interchange (DDI) ramp terminals was conducted for the first time. Crash modification factors (CMFs) were developed for DDI ramp terminals for different crash severity levels. The ramp terminal CMFs complement the project-level DDI CMFs developed in previous research. The study used data f...

In an effort to improve the safety and capacity of existing roads, many transportation practitioners are implementing innovative designs at intersections and interchanges. The development of construction phasing plans for these projects is a critical component for maintaining safety and mobility on the facility during construction. The goal of this...

The diverging diamond interchange (DDI) has gained in popularity since its first implementation in the United States in 2009. The operational benefits and lower costs of retrofitting a conventional diamond with a DDI have contributed to increased use of the DDI. Research on DDIs has focused primarily on the assessment of operational benefits. Forma...

Most crashes on high-speed rural expressways occur at intersections with minor roads. Through and left-turn movements on minor roads are especially susceptible. One low-cost alternative for improving safety of at-grade intersections on such expressways is the J-turn. This study evaluated the effectiveness of unsignalized J-turn intersection design...

Signage plays an important role in work zones to provide guidance to drivers under changed conditions. This study investigated the safety effect of an alternative merge sign configuration in a freeway work zone. In this alternative configuration, the graphical-only lane closed sign from the Manual on Uniform Traffic Control Devices (MUTCD) was comp...

None of numerous existing traffic flow forecasting models focus on work zones. Work zone events create conditions that are different from both normal operating conditions and incident conditions. In this paper, four models were developed for forecasting traffic flow for planned work zone events. The four models are random forest, regression tree, m...

Ridesharing has a long, storied history, beginning as carsharing clubs during World War II and evolving into the current technologically savvy communities. Ridesharing has traditionally enjoyed the support of public agencies at all levels of government because of the potential gains in congestion relief and environmental sustainability. However, th...

Highway maintenance often involves the use of mobile work zones for various types of low-speed moving operations, such as striping and sweeping. The speed differential between the moving operation and traffic and the increasing problem of distracted driving can lead to potential collisions between approaching vehicles and the moving work zone. One...

Variable speed limit (VSL) systems have been more widely implemented in Europe compared to the United States. Studies have demonstrated positive safety impacts of such systems; however, there are very few studies that used actual deployment data to investigate the operational benefits of VSL systems. This article presents the operational impacts of...

A lane changing assistance system that advises drivers of safe gaps for making mandatory lane changes at lane drops is developed. Bayes classifier and decision-tree methods were applied to model lane changes. Detailed vehicle trajectory data from the Next Generation Simulation (NGSIM) data set were used for model development (U.S. Highway 101) and...

The evaluation of dynamic message signs (DMSs) has been challenging to undertake because of the difficulty of identifying the effects of DMSs from traffic patterns. The primary contribution of this study is the comprehensive evaluation of DMSs in a rural area during a full freeway closure by using field data, driver surveys, and simulation. A full...

Incentive/disincentive clauses (I/D) are designed to award payments to contractors if they complete work ahead of schedule and to deduct payments if they exceed the completion time. A previously unanswered question is, Did the costs of the actual work zone impacts that were avoided justify the incentives paid? This paper answers that question affir...

Ramp metering has been successfully implemented in many states to improve traffic operations on freeways. Studies have documented the positive mobility and safety benefits of ramp metering. However, there have been no studies on the use of ramp metering for work zones. This paper reports the results from the first deployment of temporary ramp meter...

Incentive/disincentive (I/D) clauses are designed to award payments to contractors if they complete work ahead of schedule and to deduct payments if they overrun the completion time. The use of incentive/disincentive clauses in transportation is heavily influenced by the code of federal regulations. The intended effect of this regulation is to faci...

Safety improvement at nighttime work zones is important because of visibility concerns after dark. The deployment of sequential lights is an innovative method to improve driver recognition of lane closures and work zone tapers. Sequential lights are wireless warning lights that flash in a sequence to delineate clearly the taper at work zones. The e...

The 85th and 15th percentiles are two parameters that are commonly used in traffic engineering and traffic safety. For example, 85th percentile speeds are used to set speed limits and to evaluate the effectiveness of safety countermeasures, and 15th percentile speeds are used to establish typical walking speeds for traffic signal timing. But the la...

Work zone capacity is a key variable in scheduling construction activity on roadways. Understanding the effect of different definitions of capacity on the values computed from field data will result in better planning and scheduling of lane closures. Capacity values obtained using three different definitions (and methods) of capacity: (1) maximum s...

A field study was conducted on a Missouri low-volume road to examine if temporary rumble strips could improve safety in elevated-risk work zones. This study complements previous studies by addressing several new issues: vehicles that cross over a lane to bypass strips, physical displacement of strips, and deployment of strips at an angle. An object...

The classification of secondary crashes is a useful performance measure of incident management systems. Previous classification methodologies used a static threshold for classifying secondary crashes. Such a threshold represents the spatial and temporal influence of a primary incident, such as 3.2 km upstream (2 mi) and 2 h after the incident. The...

The use of electronic bills of lading (B/Ls) is a rapidly evolving area that faces much uncertainty. The intent of this paper is to provide a brief review of the history of motor carrier B/L legislation and to summarize some of the legal issues involving the use of electronic B/L such as issues related to contracts, evidence of affreightment, evide...

Evaluating the traffic impacts of work zones is vital for any transportation agency to plan and schedule work activity. Traffic impacts can be estimated by using microscopic simulation models. One challenge in using these software models is obtaining the desired work zone capacity values, which tend to vary from state to state. Thus, the default pa...

A microsimulation calibration methodology based on matching speed-flow graphs from field and simulation is presented. Evaluation and automation of matching speed-flow graphs are based on methods from pattern recognition. The methodology was applied to the US-101 freeway network in San Francisco, California, by using an evolutionary algorithm. The m...

The Delaware Memorial Bridge is a major suspension bridge that is critical to the tristate region of northern Delaware, southern New Jersey, and southeastern Pennsylvania. The Delaware Memorial Bridge consists of two nearly identical suspension bridges (hence, the nickname Twin Spans) that cross the Delaware River from southern New Jersey to northe...

The Delaware Memorial Bridge is a major suspension bridge that is critical to the tristate region of northern Delaware, southern New Jersey, and southeastern Pennsylvania. The Delaware Memorial Bridge consists of two nearly identical suspension bridges (hence, the nickname Twin Spans) that cross the Delaware River from southern New Jersey to northe...

The research that is reported describes two critical steps in developing a methodology for extracting secondary accidents from police accident databases. The eventual goal of the research is to produce an incident progression model from which the number of secondary incidents could be determined. These steps include the following: (1) the developme...

Intelligent transportation systems can play a significant role in transportation security in addition to their traditional roles in transportation operations and management. A multidetector semiautomated vehicle surveillance framework is presented. The objective of the framework is to assist in the search for a vehicle of interest involved with sec...

Intelligent transportation systems can play a significant role in transportation security in addition to their traditional roles in transportation operations and management. A multidetector semiautomated vehicle surveillance framework is presented. The objective of the framework is to assist in the search for a vehicle of interest involved with sec...

Vehicle reidentification is the process of matching vehicles from one point on the roadway (one field of view) to the next. By performing vehicle reidentification, important traffic parameters including travel time, travel time variability, section density, and partial dynamic origin/destination demands can be obtained. Field traffic data were coll...

Vehicle reidentification is the process of reidentifying or tracking vehicles from one point on the roadway to the next. By performing vehicle reidentification, important traffic parameters including travel time, section density and partial dynamic origin/destination demands can be obtained. This provides for anonymous tracking of vehicles from sit...

Improving freeway work zone traffic control could lead to more efficient traffic flow and greater safety to workers and the driving public. Newer technologies are being developed for improving work zone traffic control as in the case of dynamic speed advisory systems. Such systems have the potential to warn drivers of slow downs near work zones and...

Obtaining turning-movement counts at signalized intersections is a routine task in traffic engineering and can be tedious and time-consuming. Previous research in automating turning-movements counts focused on estimating the turning movements from approach and departure volumes and developing detection systems for exclusive-turn lanes. The accuracy...

The Department of Civil and Environmental Engineering at Rowan University (CEE-RU), with support from NSF and Rowan, will adopt "Sooner City", a virtual city developed by the School of Civil Engineering and Environmental Science (CEES-OU) at the University of Oklahoma. To be named "Garden City" at Rowan, the virtual city will provide continuity for...

As transportation surveillance technology continues to advance, the measurement of more complete traffic information is becoming increasingly feasible. ICAN stands for Inductive Classifying Artificial Network and is used to conveniently describe a self–organizing feature map (SOFM) for vehicle type categorization using inductive signatures as input...

The Accreditation Board for Engineering and Technology (ABET) and practitioners recognize professional practice issues as important in undergraduate civil engineering education. This paper describes a creative approach for incorporating professional practice issues into the civil engineering curriculum through a course entitled "Civil Engineering P...

Vehicle reidentification was investigated as a method for deriving travel time and travel time distributions with loop and video detectors. Vehicle reidentification is the process of tracking vehicles anonymously from site to site to produce individual vehicle travel times and overall travel time distribution. Travel time and travel time distributi...

Vehicle reidentification is the process of reidentifying or tracking vehicles from one point on the roadway to the next. By performing vehicle reidentification, important traffic parameters including travel time, section density and partial dynamic origin/destination demands can be obtained. This provides for anonymous tracking of vehicles from sit...

This report presents the results of Phase I of a multi-year research effort on "Field Investigation of Advanced Vehicle Reidentification Techniques and Detector Technologies," and extends previous PATH research by the authors on MOU 336 "Section-Related Measures of Traffic System Performance: Prototype Field Implementation." The focus of this resea...

In this project (MOU 336),an initial phase of a field implementation was accomplished of the results of a previous research project (MOU 224),in which a vehicle reidentification algorithm based on loop signature analysis was developed using freeway traffic data.This algorithm was extended to non-freeway cases, initially using a section of 2-lane ma...

This paper presents the results of a preliminary investigation into second-year engineering students' attitudes towards writing. Our study assesses what effect, if any, the presence of engineering faculty as part of a teaching team has on students' perceptions of the importance of writing to engineering and the overall quality of student writing. S...

Vehicle classification is the process of separating vehicles according to various predefine classes. Vehicle-classification information can be used in many transportation applications, including road maintenance, emissions/pollution estimation, traffic modeling and simulation, traffic safety, and toll setting. An example of a classification scheme...

This final report describes an advanced traffic surveillance technique based on pattern recognition and the use of current inductive loop technology. The focus of the investigation was a study of the feasibility of using inductive loop signatures for obtaining vehicle classification information on a network-wide level.

Travel time is the reciprocal of speed and is a useful measure of road congestion and traffic system performance. Travel time is also a basic traffic variable that is used in many Intelligent Transportation System (ITS) strategies such as route guidance, incident detection, and traveler information systems. Previously, speeds were mainly acquired f...

The vehicle reidentification problem is the task of matching a vehicle detected at one location with the same vehicle detected at another location from a feasible set of candidate vehicles detected at the other location. This paper formulates and solves the vehicle reidentification problem as a lexicographic optimization problem. Lexicographic opti...

Despite the advent of new detection systems such as video, infrared, microwave, and ultrasound, inductive loop detectors (ILD) still remain the most widely used sensors for traffic information. For example, the California Department of Transportation alone has approximately 300,000 ILD installations, and that number excludes the installations that...

This project describes a new set of advanced traffic surveillance techniques that are based on inductive vehicle waveforms and pattern recognition technology. Focus is on demonstrating and evaluating a new method for obtaining true selection related performance measures, such as section travel time and section density, for freeways. The report also...

The creation and progress of OAK-TREE (One-of-a-Kind Traffic Research and Education Experiment) are chronicled. OAK-TREE is a traffic educational laboratory experiment that was developed and conducted at the University of California at Irvine (UCI) during the spring quarter of 1996. This project involved a cooperative effort between the academic co...

Recent research has indicated that advances in computer memory have made the use of path-based algorithms in urban traffic networks a possibility. The path-based gradient projection (GP) offers significant benefits in computation times over the conventional Frank-Wolfe algorithm and may be especially suited for real-time applications. The computati...

Recent research has indicated that advances in computer memory have made the use of path-based algorithms in urban traffic networks a possibility. The path-based gradient projection (GP) offers significant benefits in computation times over the conventional Frank-Wolfe algorithm and may be especially suited for real-time applications. The computati...

This paper presents the results from an investigation in the use of vehicle reidentification for deriving travel time and travel time distributions using loop and video detectors. Vehicle reidentification is the process of tracking vehicles anonymously from site to site thus yielding individual vehicle travel times and overall travel time distribut...

28 29 Afghanistan and its capital, Kabul, are often in the news as they recover from the 30 years of war with the help of the international community and in particular the United 31 States. Much of the transportation infrastructure has either been damaged or has 32 deteriorated due to lack of regular maintenance over the last three decades. This ar...

The Engineering Clinic is a design course that is taken every semester by every engineering student in the College of Engineering at Rowan University. A major objective of the Sophomore Engineering Clinic I (the third course in the 8-semester sequence) is to provide the foundation necessary for students to become creative and effective engineering...