Browsing by Author "Levinson, David M."

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Access Across America
(Center for Transportation Studies, University of Minnesota, 2013-04) Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured across different times of day (accessibility in the morning rush might be lower than the less-congested midday period). It can be measured for each mode (accessibility by walking is usually lower than accessibility by transit, which is usually lower than accessibility by car). There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This report focuses on accessibility to jobs by car. Jobs are the most significant non-home destination, but it is also possible to measure accessibility to other types of destinations. The automobile remains the most widely used mode for commuting trips in the United States. This study estimates the accessibility to jobs by automobile in the 51 largest metropolitan areas in the United States for 2010, and compares results with 2000 and 1990. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes. Based on this measure, the ten metro areas that provide the greatest average accessibility to jobs are Los Angeles, San Francisco, New York, Chicago, Minneapolis, San Jose, Washington, Dallas, Boston, and Houston.
Access Across America: Auto 2016
(Center for Transportation Studies, University of Minnesota, 2018-04) Owen, Andrew; Murphy, Brendan; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured across different times of day (accessibility in the morning rush might be lower than the less-congested midday period). It can be measured for each mode (accessibility by walking is usually lower than accessibility by transit, which is usually lower than accessibility by car). There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This study estimates the accessibility to jobs by auto for each of the 11 million U.S. census blocks and analyzes these data in the 50 largest (by population) metropolitan areas. Travel times are calculated using a detailed road network and speed data that reflect typical conditions for an 8 a.m. Wednesday morning departure. Additionally, the accessibility results for 8 a.m. are compared with accessibility results for 4 a.m. to estimate the impact of road and highway congestion on job accessibility. Rankings are determined by a weighted average of accessibility, with a higher weight given to closer, easier-to-access jobs. Jobs reachable within 10 minutes are weighted most heavily, and jobs are given decreasing weights as travel time increases up to 60 minutes. The report presents detailed accessibility and congestion impact values for each metropolitan area as well as block-level maps that illustrate the spatial patterns of accessibility within each area. It also includes a census tract-level map that shows accessibility patterns at a national scale.
Access Across America: Transit 2014 Methodology
(Center for Transportation Studies, University of Minnesota, 2014-09) Owen, Andrew; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured for various transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to define accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent, as well as the most directly comparable across cities. This report describes the data and methodology used in the separate publication, Access Across America: Transit 2014 (http://hdl.handle.net/11299/168102). That report examines accessibility to jobs by transit in 46 of the 50 largest (by population) metropolitan areas in the United States. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
Access Across America: Transit 2015
(Center for Transportation Studies, University of Minnesota, 2016-12) Owen, Andrew; Murphy, Brendan; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured across different times of day (accessibility in the morning rush might be lower than the less-congested midday period). It can be measured for each mode (accessibility by walking is usually lower than accessibility by transit, which is usually lower than accessibility by car). There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This report examines accessibility to jobs by transit in 49 of the 50 largest (by population) metropolitan areas in the United States. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. This report complements Access Across America: Auto 2015, a report of job accessibility by auto in 50 metropolitan areas and follows the Access Across America: Transit 2014 report. A separate publication, Access Across America: Transit 2015 Methodology, describes the data and methodology used in this evaluation. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
Access Across America: Transit 2015 Methodology
(Center for Transportation Studies, University of Minnesota, 2016-12) Owen, Andrew; Murphy, Brendan; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured across different times of day (accessibility in the morning rush might be lower than the less-congested midday period). It can be measured for each mode (accessibility by walking is usually lower than accessibility by transit, which is usually lower than accessibility by car). There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This report describes the data and methodology used in the Access Across America: Transit 2015 report (http://hdl.handle.net/11299/183768), which examines accessibility to jobs by transit in 49 of the 50 largest (by population) metropolitan areas in the United States. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
Access Across America: Transit 2016
(Center for Transportation Studies, University of Minnesota, 2017-11) Owen, Andrew; Murphy, Brendan; Levinson, David M.
Accessibility is the ease and feasibility of reaching valued destinations. It can be measured for a wide array of transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This study estimates the accessibility to jobs by transit and walking for each of the United States’ 11 million census blocks, and analyzes these data in 49 of the 50 largest (by population) metropolitan areas. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. Travel times by transit are calculated using detailed pedestrian networks and full transit schedules for the 7:00 – 9:00 a.m. period. The calculations include all components of a transit journey, including “last-mile” access and egress walking segments and transfers, and account for minute-by-minute variations in service frequency. This report presents detailed accessibility values for each metropolitan area, as well as block-level maps that illustrate the spatial patterns of accessibility within each area. A separate publication, Access Across America: Transit 2016 Methodology, describes the data and methodology used in this evaluation.
Access Across America: Transit 2016 Methodology
(Center for Transportation Studies, University of Minnesota, 2017-11) Owen, Andrew; Murphy, Brendan; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured across different times of day (accessibility in the morning rush might be lower than the less-congested midday period). It can be measured for each mode (accessibility by walking is usually lower than accessibility by transit, which is usually lower than accessibility by car). There are a variety of ways to measure accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent as well as the most directly comparable across cities. This report describes the data and methodology used in the Access Across America: Transit 2016 report (http://hdl.handle.net/11299/194885), which examines accessibility to jobs by transit in 49 of the 50 largest (by population) metropolitan areas in the United States. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
Access Across America: Walking 2014 Methodology
(Center for Transportation Studies, University of Minnesota, 2015-05) Owen, Andrew; Levinson, David M.
Accessibility is the ease of reaching valued destinations. It can be measured for various transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to define accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent, as well as the most directly comparable across cities. This report describes the data and methodology used in the separate publication, Access Across America: Walking 2014 (http://hdl.handle.net/11299/176566). That report estimates the accessibility to jobs by walking in the 50 largest (by population) metropolitan areas in the United States. Walking mode-share for commute trips nationally is around 2.8%, and 5.0% within large cities in the United States. Rankings are determined by a weighted average of accessibility, giving a higher weight to closer jobs. Jobs reachable within ten minutes are weighted most heavily, and jobs are given decreasing weight as travel time increases up to 60 minutes.
Accessibility and the choice of network investments in the London Underground
(Journal of Transport and Land Use, 2016) Levinson, David M.; Giacomin, David; Badsey-Ellis, Antony
In 1863, the Metropolitan Railway of what came to be known as the London Underground successfully opened as the world's first subway. Its high ridership spawned interest in additional links. Entrepreneurs secured funding and then proposed new lines to Parliament for approval, though only some were actually approved. While putative rail barons may have conducted some economic analysis, the final decision lay with Parliament, which did not have modern transportation, economic, or geographic analysis tools available. How good were the decisions that Parliament made in approving Underground lines? This paper explores the role accessibility played in the decision to approve or reject proposed early London Tube schemes. It finds that maximizing accessibility to population (highly correlated with revenue and ridership) per expenditure largely explains Parliamentary approvals and rejections.
Adaptive Cruise Control System Design And Its Impact on Traffic Flow
(Center for Transportation Studies, University of Minnesota, 2005-05-01) Rajamani, Rajesh; Levinson, David M.; Michalopoulos, Panos; Wang, J.; Santhanakrishnan, Kumaragovindhan; Zhu, Xi
This study resolves the controversy over the stability of constant time-gap policy for highway traffic flow. Previous studies left doubt as to the effectiveness of constant time-gap policies and whether they maintain stability in all traffic conditions. The results of this study prove that the constant timegap policy is in fact stable to a limit. At this limit, depending on the boundary conditions, conditions lose their stability. This study develops alternative ways to maintain the balance between safety and traffic flow for ACC vehicles that does not rely on constant time-gap policies. New spacing policies will create more stability, and therefore safer conditions, and allow for greater traffic capacity.
From the Editors
(Journal of Transport and Land Use, 2008) Levinson, David M.; Krizek, Kevin J.
This article introduces the second issue of Journal of Transport and Land Use (vol. 1, no. 2).
Introducing the Journal of Transport and Land Use
(Journal of Transport and Land Use, 2008) Levinson, David M.; Krizek, Kevin J.; Dijst, Martin J.; Lo, Hong K.; Guo, Jessica Y.
This article introduces the Journal of Transport and Land Use and its inaugural issue.
Introduction: The Journal of Transport and Land Use enters year nine
(Journal of Transport and Land Use, 2016) Levinson, David M.
With this issue, the Journal of Transport and Land Use enters its ninth volume (and many articles from volume 10 can be found online under Forthcoming). Since our last update (Levinson 2013), JTLU has continued to grow and expand. Many of the articles in the issues in this and next volume were selected from papers presented at the 2014 World Symposium on Transport Land Use Research in Delft. We look forward to many more years of continued research and publication in this field.
Location, Regional Accessibility and Price Effects: Evidence from Home Sales in Hennepin County, Minnesota.
(Transportation Research Board, 2011) Iacono, Michael J; Levinson, David M.
Regional location factors, with measures of regional accessibility foremost among them, exert a strong influence on urban property markets. While accessibility represents an important regional-scale factor, more local influences such as proximity to urban highway links may also positively or negatively influence the desirability of a location. In this paper, we use a cross-section of home sales in Hennepin County, Minnesota from the years 2001 through 2004, along with a set of disaggregate regional accessibility measures, to estimate the value of access to employment and resident workers. We also estimate the (dis)amenity effects of locations near major freeway links that have recently undergone, or were scheduled to undergo (as of the time period covered by the home sales), major construction to add capacity. The richness of the home sales data set allows us to control for a number of structural attributes, as well as some site characteristics, while additional neighborhood characteristics (such as income levels and local educational quality) are added from supplemental data sources. Empirical results indicate that households highly value employment access, while access to other resident workers (i.e. competition for jobs) is considered a disamenity. Proximity to local highway access points is positively associated with sale price, while proximity to the highway link itself is negatively associated with price. The paper concludes with some implications for research and practice of the concept and measurement of the relationship between location and land value.
Safety in Numbers and Safety in Congestion for Bicyclists and Motorists at Urban Intersections
(2017) Carlson, Kristin; Ermagun, Alireza; Murphy, Brendan; Owen, Andrew; Levinson, David M.
This study assesses the estimated crashes per bicyclist and per vehicle as a function of bicyclist and vehicle traffic, and tests whether greater traffic reduces the per-car crash rate. We present a framework for comprehensive bicyclist risk assessment modeling, using estimated bicyclist flow per intersection, observed vehicle flow, and crash records. Using a two-part model of crashes, we reveal that both the annual average daily traffic and daily bicyclist traffic have a diminishing return to scale in crashes. This accentuates the positive role of safety in numbers. Increasing the number of vehicles and cyclists decelerates not only the probability of crashes, but the number of crashes as well. Measuring the elasticity of the variables, it is found that a 1% increase in the annual average daily motor vehicle traffic increases the probability of crashes by 0.14% and the number of crashes by 0.80%. However, a 1% increase in the average daily bicyclist traffic increases the probability of crashes by 0.09% and the number of crashes by 0.50%. The saturation point of the safety in numbers for bicyclists is notably less than for motor vehicles. Extracting the vertex point of the parabola functions examines that the number of crashes starts decreasing when daily vehicle and bicyclist traffic per intersection exceed 29,568 and 1,532, respectively.
Traffic Flow Variation and Network Structure
(2017) Ermagun, Alireza; Levinson, David M.
This study defines and detects competitive and complementary links in a complex network and constructs theories illustrating how the variation of traffic flow is interconnected with network structure. To test the hypotheses, we extract a grid-like sub-network containing 140 traffic links from the Minneapolis - St. Paul highway system. We reveal a real-world traffic network comprises both competitive and complementary links, and there is a negative network dependency between a competitive link pair and a positive network dependency between a complementary link pair. We validate a robust linear relationship between standard deviation of flow in a link and its number of competitive links, its link correlation with competitive links, and its network dependency with both competitive and complementary links. The results indicate the number of competitive links in a traffic network is negatively correlated with the variation of traffic flow in congested regimes as drivers are able to take alternative paths. The results also signify that the more the traffic flow of a link is correlated to the traffic flow of its competitive links, the more the flow variation is in the link. Considering the network dependency, however, it is corroborated that the more the network dependency between a link and its competitive links, the more the flow variation in the link. This is also true for complementary links.

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Browsing by Author "Levinson, David M."