The 18th Annual Engineering School of Sustainable Infrastructure and Environment (ESSIE) Poster Symposium took place on Thursday, February 18, 2016 at the Press Box in the Ben Hill Griffin Stadium. Students from all the school’s departments (Civil, Coastal and Environmental) came together to present over sixty-five abstracts on a wide array of subjects. Competition was split between undergraduates and graduates, and judged by industry professionals. These were the Transportation program’s entries:
Name: Gustavo Riente de Andrade
Degree, Year: Ph.D. Student in Civil Engineering (Transportation), 1st Year
Adviser: Dr. Lily Elefteriadou
Abstract: The breakdown of the traffic stream is defined as the transition from non-congested to congested conditions. In freeway operations, breakdowns may occur at different traffic flow levels, in a stochastic manner. The distribution of flows associated with the transition to the congested regime provides a range of possible values that can be associated to the capacity of the section.
To observe breakdown, it is necessary to locate a bottleneck. As an option, a “virtual” bottleneck can be formed at freeway ramp merging segments, when the sum of the traffic coming from the main highway and the on-ramp exceeds the capacity of the section. Breakdown events can then be identified by registering periods of time in which the speed drops below a determined threshold. The definition of the best model for breakdown probability and the ideal thresholds are still subject of research.
In this sense, previous models were developed as an analogy with reliability and life-cycle analysis, using for the estimation of the survival function the non-parametric method of Kaplan & Meier – Product Limit Method (PLM). Later studies applied this method to freeways in Florida and other American states, as well as in Germany, Israel, Japan and Brazil. The results suggested that the method is applicable and reinforced the stochastic character of capacity. As for the speed threshold, the literature suggests a range of values between 25 to 55 mph.
In this context, the objective of this work is to investigate the most recent findings on breakdown occurrence, including the definition of appropriate thresholds to classify these events, possible geometry factor that can be associated with breakdown likelihood and potential issues that might need to be addressed.
Name: Gaurav Sultania
Degree, Year: M.S. Student in Civil Engineering (Transportation), 1st Year
Adviser: Dr. Lily Elefteriadou
Abstract: Bicycle Traffic Stream behave very different to vehicular traffic stream. Various models developed for vehicles like car following model, lane changing, gap acceptance cannot be applied to bicycle streams. Because of this the simulation for traffic stream to calibrate data from the field is not very well available for bicycles. Proposed model includes cellular automata. The interaction of bicycles with pedestrians, vehicles, transits and other modes is an interesting factor that effects bicycle operations. The Level of Service measure for bicycle mode of travel for different facilities is stated in Highway Capacity Manual 2010. Various research is done after its publication to incorporate better measures of service in the upcoming manual. This paper highlights the improvement in the measures and the modelling of bicycle traffic stream.
To enhance the safety and better performance of the facility at the intersection, bicycle specific signals are installed. Experiments are done to distinguish between efficiency of different types of signal like signals with or without colored back-plate, left facing or right facing, near or far. The main challenges are to establish the minimum green time and the clearance interval. Since each bicyclist have different abilities and thus perception towards the signal to which they are unaccustomed to, it is difficult to design the time needed for yellow or all red. A comprehensive study in an environment like US where bicyclists contribute to less than 10% of total commuters is missing. This paper discusses the established tools for the evaluation of service measures for bicycle facility and the required modification.
Name: Zhengtian Xu
Degree, Year: Ph.D. Student in Civil Engineering (Transportation), 2nd Year
Adviser: Yafeng Yin
Abstract: This paper compares the effectiveness of fixed and variable congestion pricing on evolving network flows to a target flow distribution under day-to-day traffic dynamics. Fixed pricing charges constant tolls while variable pricing updates tolls every day depending on recent days’ traffic conditions. With a linear approximation of the dynamical equations, the asymptotic analysis in this paper proves that variable pricing does not necessarily perform better than fixed pricing and subsequently provides conditions when this situation can arise. Numerical experiments are presented to demonstrate the comparison.
Name: Kiarash Fariborzi
Year and Degree: M.S. Student in Civil Engineering (Transportation)
Adviser: Dr. Siva Srinivasan
Abstract: There has been growing interest in promoting non-motorized transportation modes among urban planners and policy makers in the US. Total pedestrian and bike funding rose from $ 6 million in 1990 to $1,200 million in 2009, showing an increase from 0.1% to 2% of all Federal-aid surface transportation funds (The National Bicycling and Walking Study 2010). Statistics also show that Americans have become more attracted to biking and walking with 25% increase in the NHTS (National Household Transportation Survey) reported bike and walk trips from 2001 through 2009. However, the main focus has been on walking with walking trips accounting for 10.5% of all trips while only 1% of the trips are carried out by bicycle. In addition, among all 56% of the person trips in the US which are within a reasonable biking distance (i.e. 5 miles or less), bike trips account for only 1.59% (2009 NHTS). Therefore, it is important to study cyclist travel behavior so as to find out why bike mode is not used more often and how urban planners and policy makers can promote cycling.
This study uses 2000 Bay Area Transportation Survey as dataset and binary logit model as methodology to investigate the factors affecting people’s decision to bike. 3.3% of the respondents (956 people) reported that they had biked at least once over the two days being surveyed. The focus of the study is on built environment factors (such as land use and infrastructure conditions) measured objectively while controlling for socio-demographics of the respondents. The model recognizes total of 15 variables that contribute to cycling. For the most part, the results of this study with respect to demographic variables are consistent with those of previous research; vehicle ownership, income and age are negatively correlated with bike use whereas being male and white increases the chances of biking. In addition, the study finds several built environment variables that are linked to cycling; bike lane density and street block size (an indicator of street connectivity) encourage people to bike whereas population density is a deterrent to cyclists. The study also indicates that socio-demographic factors play a key role in bicycle use, with relatively higher contribution to cycling compared to environmental factors. Finally, In terms of bike-use research methodology, this study finds that exclusion of zero-bike households from the estimation sample does not significantly improve prediction capability of bike-use models.
Name: Eleftheria (Ria) Kontou
Degree: Ph.D. Student in Civil Engineering (Transportation), 3rd Year
Adviser: Dr. Yafeng Yin
Abstract: In this paper, we provide insights on the timeframe needed for society to achieve optimal transition from conventional to all-electric vehicle technologies. An optimization framework is developed to determine the all-electric driving range that the electric vehicles should be characterized from and we optimize the density of chargers that should be placed on the linear transportation network of our study. The framework is applied using data that represent the United States households, and the energy and the automobile markets. We explore the effects of the markets’ parameters on the optimal electrification process for the U.S. household fleet.
Name: Deja M. Jackson
Degree: Ph.D. Student in Civil Engineering (Transportation), 1st Year
Adviser: Siva Srinivasan, PhD
Abstract: As a result of new and emerging vehicle safety technologies, vehicle safety has evolved from basic seatbelts and airbags to high-tech safety features, thus making today’s vehicles the safest in history. These continuous innovations in safety have contributed to a steady yearly reduction in the number of crash-related injuries and fatalities.
A lot of vehicle safety technology has been introduced since many consumers bought their last vehicle. Consequently, a lot of consumers may not be aware of current vehicle safety features available. Previous studies have shown that safety is a critical component when making the decision to purchase a car, therefore, this research aims to identify the current knowledge and attitudes among consumers regarding vehicle safety features available in today’s vehicles, the willingness to pay for these features, and specific concerns or barriers that would prevent consumers from acquiring vehicles with the mentioned safety features. A qualitative approach was taken for preliminary research purposes and included an informal online survey.