A multi-agent model of travelers competing to utilize a roadway in time and space is presented in... more A multi-agent model of travelers competing to utilize a roadway in time and space is presented in this paper to illustrate the effect of congestion and pricing on traveler behaviors and network equilibrium. To realize the spillover effect among travelers, N-player games are constructed in which the strategy set includes N+1 strategies. We solve the N-player game (for N ≤ 7) and find Nash equilibria if they exist. This model is compared to the bottleneck model. The results of numerical simulation show that the two models yield identical results in terms of lowest total costs and marginal costs when a social optimum exists.
The impact of gasoline price changes on traffic safety has received increasing attention in empir... more The impact of gasoline price changes on traffic safety has received increasing attention in empirical studies. However, this important relationship has not been explained within a conceptual or theoretical framework. In this study, we examine this relationship within a time geography framework in an attempt to understand the effect of time-varying fluctuations in gasoline prices and their relationship to traffic
Gasoline prices have significant effects on traffic safety. However, existing literature has fail... more Gasoline prices have significant effects on traffic safety. However, existing literature has failed to adequately investigate the effects: the literature has examined only fatal incidents rather than total traffic incidents. This study analyzes the effects of gasoline prices on total traffic incidents and on the incidents by age and gender. The results suggest that gasoline prices have negative short-term effects
The US Department of Health and Human Services Administration on Development Disabilities estimat... more The US Department of Health and Human Services Administration on Development Disabilities estimates the number of people diagnosed with a developmental disability in the United States as 4.5 million persons, which would translate to about 17,000 residents of Hennepin County, Minnesota. This research paper examines the transportation needs of adults with developmental disabilities either residing or working in Hennepin County through a survey of their existing travel behavior and their unmet transportation needs. The survey had both demographic and attitude questions as well as a travel diary to record both actual and desired but untaken trips. In this paper we report and discuss the main findings of the survey. It was clear from observing the returned sample that almost the entire surveyed population does not live independently. More than half of the surveyed population worked every day, while recreation occurred at least once a week for about two-thirds of the population, and more than half undertook social trips weekly. About 30% reported being unable to make trips they want to make and 46% unable to make trips they need to make. Public transit poses difficulties for this population both physically and intellectually. There were also specific complaints about the lack of transit service in addition to concerns regarding paratransit services. Community service providers received praise.
Transportation systems are built with the intention to serve communities by providing accessibili... more Transportation systems are built with the intention to serve communities by providing accessibility and mobility. Yet seniors residing in these communities face different challenges compared to regular commuters. Seniors have special needs in terms of desired destinations and challenges faced due to limitations in mobility and decline of accessibility levels where they reside. In this research paper we discuss major findings from a mail-out mail-in survey conducted in Hennepin County, Minnesota to measuring met and unmet urban transportation needs of seniors. Compared to previous research this study uses primary collected data rather than relying on travel surveys, which does not measure the unmet urban transportation needs of seniors. The findings from this survey is consistent in term of measuring the existing travel behavior of seniors, which raises our confidence in the information being collected related to the unmet transportation needs of seniors. Seniors are found to be generally independent and rely mainly on auto usage to reach desired destinations at higher rates compared to the rest of the population. The majority of seniors reported although they are currently independent they do know that such independency is not permanent and they have to learn more about alternatives available to them. This study helps transportation engineers and planners in better understanding the current and future challenges that they will face with an aging population.
Accessibility measures the potential of opportunities for interaction. This paper pro- poses a ne... more Accessibility measures the potential of opportunities for interaction. This paper pro- poses a new ow-based accessibility measure, \place rank" utilizing origin-destination information. Both impedance and value of opportunities are embedded in the dataset that includes origins and destination of each person utilizing the studied region. In- dividuals contribute to the accessibility level in their destination (work) zone with a dierent
Modern urban regions are highly complex entities. Despite the difficulty of modeling every releva... more Modern urban regions are highly complex entities. Despite the difficulty of modeling every relevant aspect of an urban region, researchers have produced a rich variety models dealing with inter-related processes of urban change. The most popular types of models have been those dealing with the relationship between transportation network growth and changes in land use and the location of economic
The set of models available to predict land use change in urban regions has become increasingly c... more The set of models available to predict land use change in urban regions has become increasingly complex in recent years. Despite their complexity, the predictive power of these models remains relatively weak. This paper presents an example of an alternative modeling framework based on the concept of a Markov chain. The model assumes that land use at any given time,
This study evaluates individual preferences for five different cycling environments by trading of... more This study evaluates individual preferences for five different cycling environments by trading off a higher travel time as a cost incurred when choosing a better facility while letting the user have the option of selecting a less attractive facility at a lower travel time. The tradeoff of travel time to amenities of a particular facility informs our understanding of the
This research develops and applies a new structure for the transportation planning model that inc... more This research develops and applies a new structure for the transportation planning model that includes feedback between demand, assignment, and traffic control. New methods, combined with a renewed interest in transportation planning models prompted by the Clean Air Act of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991, warrant a reconsideration of the traditional "four-step" transportation planning model.
An efficient ramp control strategy may not be politically attractive due to its negative impacts ... more An efficient ramp control strategy may not be politically attractive due to its negative impacts on equity. This paper addresses this issue and presents a new objective for ramp metering—minimizing weighted travel time—which is able to balance efficiency and equity. A quasioptimization/simulation approach is used to achieve the new objective. BEEX, a new family of control strategies with various degrees
This study investigates the allocation of time and trip-making across time-of-day, day-of-week, a... more This study investigates the allocation of time and trip-making across time-of-day, day-of-week, and month-of-year, as well as over the past forty years. Some interesting findings result. People are working much more, shopping somewhat more on weekends, and stay at home less today than forty years ago. Time spent in travel on each weekend day (Saturday or Sunday) exceeds that on
Transit information systems are crucial for informing riders of their location, destination, and ... more Transit information systems are crucial for informing riders of their location, destination, and arrival time. After reviewing and classifying the various types of transit information systems, an adaptive stated preference survey was developed and administered to determine the value of information for transit users. The survey consisted of two scenarios which included a picture and a written description. In a
Problem: Limited literature suggests that gasoline prices have substantial effects on reducing fa... more Problem: Limited literature suggests that gasoline prices have substantial effects on reducing fatal crashes. However, the literature focuses only on fatal crashes and does not examine the effects on all traffic crashes. Methods: Mississippi traffic crash data from April 2004-December 2008 from the Mississippi Highway Patrol and regular-grade unleaded gasoline price data from the Energy Information Administration of the U.S. Department of Energy were used to investigate the effects of gasoline prices on traffic safety by age, gender, and race. Results: Gasoline prices have both short-term and intermediate-term effects on reducing total traffic crashes and crashes of females, whites, and blacks. The intermediate-term effects are generally stronger than the short-term effects. Gasoline prices also have short-term effects on reducing crashes of younger drivers and intermediate-term effects on older drivers and male drivers. Impact on Industry: Higher gasoline taxes reduce traffic crashes and may result in additional societal benefits. 5 Traffic safety encompasses both decreases and increases in traffic crashes. 0022-4375/$see front matter
Carrion and Levinson (2012) studied the bridge choice behavior of commuters before and after a ne... more Carrion and Levinson (2012) studied the bridge choice behavior of commuters before and after a new bridge opened to the public. This bridge replaced the previously collapsed I-35W bridge in the metro area of Minneapolis-St. Paul. The original I-35W bridge collapsed on August 1st 2007, and the replacement bridge opened to the public on September 18th 2008. This study extends
The dominant method for measuring values of travel time savings (VOT), and values of travel time ... more The dominant method for measuring values of travel time savings (VOT), and values of travel time reliability (VOR) is discrete choice modeling. Generally, the data sources for these models are: stated choice experiments, and revealed preference observations. There are few studies using revealed preference data. These studies have only used travel times measured by devices such as loop detectors, and
Travel time reliability is a fundamental factor in travel behavior. It represents the temporal un... more Travel time reliability is a fundamental factor in travel behavior. It represents the temporal uncertainty experienced by travelers in their movement between any two nodes in a network. The importance of the time reliability depends on the penalties incurred by the travelers. In road networks, travelers consider the existence of a trip travel time uncertainty in different choice situations (departure
This study considers the influence of the knowledge of existing mode shares on travelers mode cho... more This study considers the influence of the knowledge of existing mode shares on travelers mode choice. This contrasts with traditional mode choice models, where the main objective is to predict the overall mode shares as the aggregate of individual mode choices according to variables encompassing attributes of the modes, and characteristics of the travelers. In this study, a computer-administered adaptive
Monte Carlo experiments are used to study the unbiasedness of several common random utility model... more Monte Carlo experiments are used to study the unbiasedness of several common random utility models for a proposed adaptive stated preference survey. This survey is used to study the influence of the knowledge of existing mode shares on travelers mode choice. Furthermore, the survey is applied to a sample of subjects selected from the University of Minnesota. The results indicate
A multi-agent model of travelers competing to utilize a roadway in time and space is presented in... more A multi-agent model of travelers competing to utilize a roadway in time and space is presented in this paper to illustrate the effect of congestion and pricing on traveler behaviors and network equilibrium. To realize the spillover effect among travelers, N-player games are constructed in which the strategy set includes N+1 strategies. We solve the N-player game (for N ≤ 7) and find Nash equilibria if they exist. This model is compared to the bottleneck model. The results of numerical simulation show that the two models yield identical results in terms of lowest total costs and marginal costs when a social optimum exists.
The impact of gasoline price changes on traffic safety has received increasing attention in empir... more The impact of gasoline price changes on traffic safety has received increasing attention in empirical studies. However, this important relationship has not been explained within a conceptual or theoretical framework. In this study, we examine this relationship within a time geography framework in an attempt to understand the effect of time-varying fluctuations in gasoline prices and their relationship to traffic
Gasoline prices have significant effects on traffic safety. However, existing literature has fail... more Gasoline prices have significant effects on traffic safety. However, existing literature has failed to adequately investigate the effects: the literature has examined only fatal incidents rather than total traffic incidents. This study analyzes the effects of gasoline prices on total traffic incidents and on the incidents by age and gender. The results suggest that gasoline prices have negative short-term effects
The US Department of Health and Human Services Administration on Development Disabilities estimat... more The US Department of Health and Human Services Administration on Development Disabilities estimates the number of people diagnosed with a developmental disability in the United States as 4.5 million persons, which would translate to about 17,000 residents of Hennepin County, Minnesota. This research paper examines the transportation needs of adults with developmental disabilities either residing or working in Hennepin County through a survey of their existing travel behavior and their unmet transportation needs. The survey had both demographic and attitude questions as well as a travel diary to record both actual and desired but untaken trips. In this paper we report and discuss the main findings of the survey. It was clear from observing the returned sample that almost the entire surveyed population does not live independently. More than half of the surveyed population worked every day, while recreation occurred at least once a week for about two-thirds of the population, and more than half undertook social trips weekly. About 30% reported being unable to make trips they want to make and 46% unable to make trips they need to make. Public transit poses difficulties for this population both physically and intellectually. There were also specific complaints about the lack of transit service in addition to concerns regarding paratransit services. Community service providers received praise.
Transportation systems are built with the intention to serve communities by providing accessibili... more Transportation systems are built with the intention to serve communities by providing accessibility and mobility. Yet seniors residing in these communities face different challenges compared to regular commuters. Seniors have special needs in terms of desired destinations and challenges faced due to limitations in mobility and decline of accessibility levels where they reside. In this research paper we discuss major findings from a mail-out mail-in survey conducted in Hennepin County, Minnesota to measuring met and unmet urban transportation needs of seniors. Compared to previous research this study uses primary collected data rather than relying on travel surveys, which does not measure the unmet urban transportation needs of seniors. The findings from this survey is consistent in term of measuring the existing travel behavior of seniors, which raises our confidence in the information being collected related to the unmet transportation needs of seniors. Seniors are found to be generally independent and rely mainly on auto usage to reach desired destinations at higher rates compared to the rest of the population. The majority of seniors reported although they are currently independent they do know that such independency is not permanent and they have to learn more about alternatives available to them. This study helps transportation engineers and planners in better understanding the current and future challenges that they will face with an aging population.
Accessibility measures the potential of opportunities for interaction. This paper pro- poses a ne... more Accessibility measures the potential of opportunities for interaction. This paper pro- poses a new ow-based accessibility measure, \place rank" utilizing origin-destination information. Both impedance and value of opportunities are embedded in the dataset that includes origins and destination of each person utilizing the studied region. In- dividuals contribute to the accessibility level in their destination (work) zone with a dierent
Modern urban regions are highly complex entities. Despite the difficulty of modeling every releva... more Modern urban regions are highly complex entities. Despite the difficulty of modeling every relevant aspect of an urban region, researchers have produced a rich variety models dealing with inter-related processes of urban change. The most popular types of models have been those dealing with the relationship between transportation network growth and changes in land use and the location of economic
The set of models available to predict land use change in urban regions has become increasingly c... more The set of models available to predict land use change in urban regions has become increasingly complex in recent years. Despite their complexity, the predictive power of these models remains relatively weak. This paper presents an example of an alternative modeling framework based on the concept of a Markov chain. The model assumes that land use at any given time,
This study evaluates individual preferences for five different cycling environments by trading of... more This study evaluates individual preferences for five different cycling environments by trading off a higher travel time as a cost incurred when choosing a better facility while letting the user have the option of selecting a less attractive facility at a lower travel time. The tradeoff of travel time to amenities of a particular facility informs our understanding of the
This research develops and applies a new structure for the transportation planning model that inc... more This research develops and applies a new structure for the transportation planning model that includes feedback between demand, assignment, and traffic control. New methods, combined with a renewed interest in transportation planning models prompted by the Clean Air Act of 1990 and the Intermodal Surface Transportation Efficiency Act of 1991, warrant a reconsideration of the traditional "four-step" transportation planning model.
An efficient ramp control strategy may not be politically attractive due to its negative impacts ... more An efficient ramp control strategy may not be politically attractive due to its negative impacts on equity. This paper addresses this issue and presents a new objective for ramp metering—minimizing weighted travel time—which is able to balance efficiency and equity. A quasioptimization/simulation approach is used to achieve the new objective. BEEX, a new family of control strategies with various degrees
This study investigates the allocation of time and trip-making across time-of-day, day-of-week, a... more This study investigates the allocation of time and trip-making across time-of-day, day-of-week, and month-of-year, as well as over the past forty years. Some interesting findings result. People are working much more, shopping somewhat more on weekends, and stay at home less today than forty years ago. Time spent in travel on each weekend day (Saturday or Sunday) exceeds that on
Transit information systems are crucial for informing riders of their location, destination, and ... more Transit information systems are crucial for informing riders of their location, destination, and arrival time. After reviewing and classifying the various types of transit information systems, an adaptive stated preference survey was developed and administered to determine the value of information for transit users. The survey consisted of two scenarios which included a picture and a written description. In a
Problem: Limited literature suggests that gasoline prices have substantial effects on reducing fa... more Problem: Limited literature suggests that gasoline prices have substantial effects on reducing fatal crashes. However, the literature focuses only on fatal crashes and does not examine the effects on all traffic crashes. Methods: Mississippi traffic crash data from April 2004-December 2008 from the Mississippi Highway Patrol and regular-grade unleaded gasoline price data from the Energy Information Administration of the U.S. Department of Energy were used to investigate the effects of gasoline prices on traffic safety by age, gender, and race. Results: Gasoline prices have both short-term and intermediate-term effects on reducing total traffic crashes and crashes of females, whites, and blacks. The intermediate-term effects are generally stronger than the short-term effects. Gasoline prices also have short-term effects on reducing crashes of younger drivers and intermediate-term effects on older drivers and male drivers. Impact on Industry: Higher gasoline taxes reduce traffic crashes and may result in additional societal benefits. 5 Traffic safety encompasses both decreases and increases in traffic crashes. 0022-4375/$see front matter
Carrion and Levinson (2012) studied the bridge choice behavior of commuters before and after a ne... more Carrion and Levinson (2012) studied the bridge choice behavior of commuters before and after a new bridge opened to the public. This bridge replaced the previously collapsed I-35W bridge in the metro area of Minneapolis-St. Paul. The original I-35W bridge collapsed on August 1st 2007, and the replacement bridge opened to the public on September 18th 2008. This study extends
The dominant method for measuring values of travel time savings (VOT), and values of travel time ... more The dominant method for measuring values of travel time savings (VOT), and values of travel time reliability (VOR) is discrete choice modeling. Generally, the data sources for these models are: stated choice experiments, and revealed preference observations. There are few studies using revealed preference data. These studies have only used travel times measured by devices such as loop detectors, and
Travel time reliability is a fundamental factor in travel behavior. It represents the temporal un... more Travel time reliability is a fundamental factor in travel behavior. It represents the temporal uncertainty experienced by travelers in their movement between any two nodes in a network. The importance of the time reliability depends on the penalties incurred by the travelers. In road networks, travelers consider the existence of a trip travel time uncertainty in different choice situations (departure
This study considers the influence of the knowledge of existing mode shares on travelers mode cho... more This study considers the influence of the knowledge of existing mode shares on travelers mode choice. This contrasts with traditional mode choice models, where the main objective is to predict the overall mode shares as the aggregate of individual mode choices according to variables encompassing attributes of the modes, and characteristics of the travelers. In this study, a computer-administered adaptive
Monte Carlo experiments are used to study the unbiasedness of several common random utility model... more Monte Carlo experiments are used to study the unbiasedness of several common random utility models for a proposed adaptive stated preference survey. This survey is used to study the influence of the knowledge of existing mode shares on travelers mode choice. Furthermore, the survey is applied to a sample of subjects selected from the University of Minnesota. The results indicate
Uploads
Papers by David Levinson