Dr. David M. Levinson
Persistent link for this collectionhttps://hdl.handle.net/11299/179806
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Browsing Dr. David M. Levinson by Type "Working Paper"
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Item Accessibility Analysis of Risk Severity(2015) Cui, Mengying; Levinson, David, MRisk severity in transportation network analysis is defined as the effects of a link or network failure on the whole system. Change accessibility (reduction in the number of jobs which can be reached) is used as an integrated indicator to reflect the severity of a link outage. The changes of accessibility before-and-after the removing of a freeway segment from the network represent its risk severity. The analysis in the Minneapolis - St. Paul (Twin Cities) region show that links near downtown Minneapolis have relative higher risk severity than those in rural area. The geographical distribution of links with the highest risk severity displays the property that these links tend to be near or at the intersection of freeways. Risk severity of these links based on the accessibility to jobs and to workers at different time thresholds and during different dayparts are also analyzed in the paper. The research finds that network structure measures: betweenness, straightness and closeness, help explain the severity of loss due to network outage.Item Accessibility and Centrality Based Estimation of Urban Pedestrian Activity(2015) Murphy, Brendan; Levinson, David, M; Owen, AndrewNon-motorized transportation, particularly including walking and bicycling, are increasingly becoming important modes in modern cities, for reasons including individual and societal wellness, avoiding negative environmental impacts of other modes, and resource availability. Institutions governing development and management of urban areas are increasingly keen to include walking and bicycling in urban planning and engineering; however, proper placement of improvements and treatments depends on the availability of good usage data. This study attempts to predict pedestrian activity at 1123 intersections in the Midwestern, US city of Minneapolis, Minnesota, using scalable and transferable predictive variables such as economic accessibility by sector, betweenness network centrality, and automobile traffic levels. Accessibility to jobs by walking and transit, automobile traffic, and accessibility to certain economic job categories (Education, Finance) were found to be significant predictors of increased pedestrian traffic, while accessibility to other economic job categories (Management, Utilities) were found to be significant predictors of decreased pedestrian traffic. Betweenness centrality was not found to be a significant predictor of pedestrian traffic, however the specific calculation methodology can be further tailored to reflect real-world pedestrian use-cases in urban areas. Accessibility-based analysis may provide city planners and engineers with an additional tool to predict pedestrian and bicycle traffic where counts may be difficult to obtain, or otherwise unavailable.Item Accessibility and the Ring of Unreliability(2016) Cui, Mengying; Levinson, David, MThis study measures the variability of job accessibility via automobile for the Minneapolis-St. Paul region. The accessibility analysis uses cumulative opportunity measures. The travel times on the network are tested at various level (10th percentile speed, 50th percentile speed, 90th percentile speed) using the TomTom speed data for 2010. It is shown that accessibility varies widely day-to-day as travel speeds on the network vary. Some parts of the region (a ring around the core) have more volatility in accessibility (and are thus less reliable) than others.Item Accessibility and Transit Performance(2015) Ermagun, Alireza; Levinson, David, MThis study disentangles the impact of financial and physical dimensions of transit service operators on net transit accessibility for 46 of the 50 largest metropolitan areas in the United States. To investigate this interaction along with the production efficiency of transit agencies, two types of analysis are used: a set of linear and quadratic regressions and a data envelopment analysis. We find that vehicle revenue kilometers and operational expenses play a pivotal role in enhancing the accessibility to jobs by transit. The bivariate linear regression models indicate a 1% increase in operational expenses and vehicle revenue kilometers increase the number of jobs that can be reached within 30 minutes by 0.96 and 0.95%, respectively. The results of the quadratic functional form, also, show transit services may have both increasing and decreasing accessibility returns to scale depending on system size, and the results are sensitive to the model used. Overall, the highest system efficiency (access produced per input) is found in the New York, Washington, and Milwaukee metropolitan areas, while Riverside, Detroit, and Austin perform with the lowest efficiency.Item Accessibility-based Evaluation of Transit Projects(2016-08-01) Palmateer, Chelsey; Owen, Andrew; Levinson, David M; Ermagun, AlirezaThis study uses the accessibility-based evaluation method to unpack the interaction effect of transit oriented development and a new transit hub, using the San Francisco Transbay Transit Center Development Plan project. We reveal both the transit oriented development and transit changes positively affect accessibility to jobs and accessibility to workers. However, the magnitude of effects for the transit changes alone are minimal in comparison to the effects of the anticipated transit oriented development changes. This indicates that in areas where there already is transit service, the development of land near the transit service can have a greater impact on accessibility levels than the improvement of connections between transit services. We also unravel the increase in accessibility at the project-level and determine that the increase is greater than the sum of the contributions of the individual portions of the project. This demonstrates that transit changes and transit oriented development have a superadditive effect, although it is negligible in our case.Item Accessibility-oriented development(2017) Deboosere, Robbin; Levinson, David M; El-Geneidy, AhmedMunicipal governments worldwide have been pursuing transit-oriented development (TOD) strategies in order to increase transit ridership, curb traffic congestion, and rejuvenate urban neighborhoods. In many cities, however, development of planned sites around transit stations has been close to non-existent, due to, among other reasons, a lack of coordination between transit investments and land use at the regional scale. Furthermore, the ability to access transit differs from the ability to access destinations that people care about. Reframing transit-oriented development as accessibility-oriented development (AOD) can aid the process of creating functional connections between neighborhoods and the rest of the region, and maximize benefits from transport investments. AOD is a strategy that balances accessibility to employment and the labor force in order to foster an environment conducive to development. AOD areas are thus defined as having higher than average accessibility to employment opportunities and/or the labor force; such accessibility levels are expected to increase the quality of life of residents living in these areas by reducing their commute time and encouraging faster economic development. To quantify the benefits of AOD, accessibility to employment and the labor force are calculated in the Greater Toronto and Hamilton Area, Canada in 2001 and 2011. Cross-sectional and temporal regressions are then performed to predict average commute times and development occurring in AOD areas and across the region. Results show that AOD neighborhoods with high accessibility to jobs and low accessibility to the labor force have the lowest commute times in the region, while the relationship also holds for changes in average commute time between the studied time periods. In addition, both accessibility to jobs and accessibility to the labor force are associated with changes in development, as areas with high accessibility to jobs and the labor force attract more development. In order to realize the full benefits of planned transit investments, planning professionals and policy makers alike should therefore leverage accessibility as a tool to direct development in their cities, and concentrate on developing neighbourhoods with an AOD approach in mind.Item An Agent-based Route Choice Model(2007) Zhu, Shanjiang; Levinson, David M; Zhang, LeiTravel demand emerges from individual decisions. These decisions, depending on individual objectives, preferences, experiences and spatial knowledge about travel, are both heterogeneous and evolutionary. Research emerging from fields such as road pricing and ATIS requires travel demand models that are able to consider travelers with distinct attributes (value of time (VOT), willingness to pay, travel budgets, etc.) and behavioral preferences (e.g. willingness to switch routes with potential savings) in a differentiated market (by tolls and the level of service). Traditional trip-based models have difficulty in dealing with the aforementioned heterogeneity and issues such as equity. Moreover, the role of spatial information, which has significant influence on decision-making and travel behavior, has not been fully addressed in existing models. To bridge the gap, this paper proposes to explicitly model the formation and spread- ing of spatial knowledge among travelers. An Agent-based Route Choice (ARC) model was developed to track choices of each decision-maker on a road network over time and map individual choices into macroscopic flow pattern. ARC has been applied on both SiouxFalls network and Chicago sketch network. Comparison between ARC and existing models (UE and SUE) on both networks shows ARC is valid and computationally tractable. To be brief, this paper specifically focuses on the route choice behavior, while the proposed model can be extended to other modules of travel demand under an integrated framework.Item Benefit-Cost Analysis of Spring Weight Restrictions in Lyon County, Minnesota(2004) Ning, Li; Levinson, David M; Smalkoski, Brian; Corbett, MichaelSpring Weight Restrictions (SWR) forbid heavy trucks to run on some low- level roads during the spring thaw period. There has been long dispute between trucking industry and road agencies on the effectiveness of this policy. Previous studies showed inconsistent results on this issue. This paper consistently estimates the benefits and costs of the SWR policy in Lyon County, Minnesota. A freight demand model was built to simulate truck flow on the road network. A pavement performance model estimates pavement life in terms of rutting failure based on the traffic provided by freight demand model. The analysis shows that the benefits of SWR to local agencies are exceeded by the costs to truckers, which suggests lifting these seasonal restrictions on 7 and 9-ton roads.Item Choice of High Occupancy/Toll Lanes Under Alternative Pricing Strategies(2014) Janson, Michael; Levinson, David MHigh Occupancy/Toll (HOT) Lanes typically charge a varying to single occupant vehicles (SOVs), with the toll increasing during more congested periods. The toll is usually tied to time of day or to the density of vehicles in the HOT lane. The purpose of raising the toll with congestion is to discourage demand enough to maintain a high level of service (LOS) in the HOT lane. Janson and Levinson (2014) demonstrated that the HOT toll may act as a signal of downstream congestion (in both general purpose (GP) and HOT lanes), causing an increase in demand for the HOT lane, at least at lower prices. This paper builds off that research and explores alternative HOT lane pricing strategies, including the use of GP density as a factor in price to more accurately reflect the value of the HOT lane. In addition, the paper explores the potential effect these strategies would have on the HOT lane vehicle share through a partial equilibrium analysis. This analysis demonstrates the change in demand elasticity with price, showing the point at which drivers switch from a positive to negative elasticity.Item The City is Flatter: Changing Patterns of Job and Labor Access in Minneapolis-Saint Paul, 1995-2005(2010) Levinson, David M; Marion, BernadetteThis study describes the measurement of accessibility by automobile for the Minneapolis - Saint Paul (Twin Cities) region over the period from 1995 to 2005. In contrast to previous analyses of accessibility, this study uses travel time estimates derived, to the extent possible, from actual observations of network performance by time of day. A set of cumulative opportunity measures are computed with transportation analysis zones (TAZs) as the unit of analysis for 1995 and 2005. Analysis of the changes in accessibility by location over the period of study reveals that, for the majority of locations in the region, accessibility increased over this period, though the increases were not uniform. A “flattening” or convergence of levels of accessibility across locations was observed over time, with faster-growing suburban locations gaining the most in terms of employment accessibility. An effort to decompose the causes of changes in accessibility into components related to transportation network structure and land use (opportunity location) reveal that both causes make a contribution to increasing accessibility, though the effects of changes to the transportation network tend to be more location-specific. Overall, the results of the study demonstrate the feasibility and relevance of using accessibility as a key performance measure to describe the regional transportation system.Item Cohort Effects and Their Influence on Car Ownership(2015) Iacono, Michael, J; Levinson, David, MRecent trends in the United States suggest a movement toward saturation of vehicle ownership. This paper examines this trend through an analysis of car ownership in the Minneapolis- St. Paul, Minnesota (USA) metropolitan region. Data from pooled cross-sectional household surveys are used to calibrate a model of car ownership that includes birth cohort effects to capture unobserved variations in preference toward car ownership across generations. Declines in household size and worker status have significant impacts in limiting the growth of car ownership, but they are also coupled by an apparent softening of preferences toward ownership among young adults.Item Contacts and Meetings: Location, Duration and Distance Traveled(2009) Tilahun, Nebiyou J; Levinson, David MThe role of contacts on travel behavior has been getting increasing attention. This paper reports on data collected on individual’s social meetings and the choice of in-home/out-of-home meeting locations as well as the distance travelled and duration of out-home-meetings and its relationship to the type of contact met and other attributes of the meeting. Empirically we show that in-home meetings tend to occur most often with close contacts and less often with distant contacts. The purpose, meeting day, and household size suggest that leisure, weekend and large household size people tend to have their meetings either at their home or at their contact’s home. In addition when meetings occur outside of the house, the duration is longer for close contacts and distance to the meeting location is directly influenced by duration and indirectly by the relationship type. Overall the paper illustrates that relationship type along with other meeting specific and demographic variables is important in explaining the location, duration and distance travelled for social meetings.Item The cost of equity: Assessing transit accessibility and social disparity using total travel cost(2016) El-Geneidy, Ahmed; Levinson, David, M; Diab, Ehab; Boisjoly, Genevieve; Verbich, David; Loong, CharisSocial equity is increasingly incorporated as a long-term objective into urban transportation plans. Researchers used accessibility measures to assess equity issues, such as determining the amount of jobs reachable by marginalized groups within a defined travel time threshold and compare these measures across socioeconomic categories. However, allocating public transit resources in an equitable manner is not only related to travel time, but also related to the out-of- pocket cost of transit fares, which can represent a major barrier to accessibility for many disadvantaged groups. Therefore, this research proposes a set of new accessibility measures that incorporates both travel time and transit fares. It then applies those measures to determine whether people residing in socially disadvantaged neighborhoods in Montreal, Canada experience the same levels of transit accessibility as those living in other neighborhoods. Results are presented in terms of regional accessibility and trends by social indicator decile. Travel time accessibility measures estimate a higher number of jobs that can be reached compared to combined travel time and cost measures. However, the degree and impact of these measures varies across the social deciles. Compared to other groups in the region, residents of socially disadvantaged areas have more equitable accessibility to jobs using transit; this is reflected in smaller decreases in accessibility when fare costs are included. Generating new measures of accessibility combining travel time and transit fares provides more accurate measures that can be easily communicated by transportation planners and engineers to policy makers and the public since it translates accessibility measures to a dollar value.Item Detecting the Breakdown of Traffic(2006) Zou, Xi; Levinson, David MTimely traffic prediction is important in advanced traffic management systems to make possible rapid and effective response by traffic control facilities. From the observations of traffic flow, the time series present repetitive or regular behavior over time that distinguishes time series analysis of traffic flow from classical statistics, which assumes independence over time. By taking advantage of tools in frequency domain analysis, this paper proposes a new criterion function that can detect the onset of congestion. It is found that the changing rate of the cross-correlation between density dynamics and flow rate determines traffic transferring from free flow phase to the congestion phase. A definition of traffic stability is proposed based on the criterion function. The new method suggests that an unreturnable transition will occur only if the changing rate of the cross-correlation exceeds a threshold. Based on real traffic data, detection of congestion is conducted in which the new scheme performs well compared to previous studies.Item Development and Application of the Network Weight Matrix to Predict Traffic Flow for Congested and Uncongested Conditions(2016-08-01) Ermagun, Alireza; Levinson, David MTo capture a more realistic spatial dependence between traffic links, we introduce two distinct network weight matrices to replace spatial weight matrices used in traffic forecasting methods. The first stands on the notion of betweenness centrality and link vulnerability in traffic networks. To derive this matrix, we assume all traffic flow is assigned to the shortest path, and thereby we used Dijkstra's algorithm to find the shortest path. The other relies on flow rate change in traffic links. For forming this matrix, we employed user equilibrium assignment and the method of successive averages (MSA) algorithm to solve the network. The components of the network weight matrices are a function not simply of adjacency, but of network topology, network structure, and demand configuration. We tested and compared the network weight matrices in different traffic conditions using Nguyen-Dupuis network. The results led to a clear and unshakable conclusion that spatial weight matrices are unable to capture the realistic spatial dependence between traffic links in a network. Not only do they overlook the competitive nature of traffic links, but they also ignore the role of network topology and demand configuration. In contrast, the flow-weighted betweenness method significantly operates better than unweighted betweenness to measure realistic spatial dependence between traffic links, particularly in congested traffic conditions. The results disclosed that this superiority is more than 2 times in congested flow situations. However, forming this matrix requires considerable computational effort and information. If the network is uncongested the network weight matrix stemming from betweenness centrality is sufficient.Item Does poor road condition increase crashes?(2016-08-01) Yokoo, Toshihiro; Levinson, David M; Marasteanu, MihaiIn a region well known for its severe weather, maintaining pavements to meet high standards remains a challenge. Changes in weather states (such as the freeze-thaw cycle) leads to distresses in the pavement materials. There exist claims that poor pavement quality reduces the ability of roads to drain and reduces the ability of vehicles to resist skidding, and is thus associated with more crashes. In order to improve road safety, several pavement maintenance treatments are carried out, such as “rout and seal cracks” and “hot-mix patching” for improving pavement roughness and distress (Tighe et al., 2000). Others have found that crash rate depends on the pavement type and pavement condition. Crash rate of tined pavement sites is larger than the rate of ground pavement sites. When the pavement condition is wet or icy, crashes are more likely than under dry conditions (Drakopoulos et al., 1998). , When the pavement condition is poor, severe crashes are more likely, but when the pavement condition is very poor, severe crashes are less likely to occur than poor pavement conditions (Li et al., 2013). In accident rate estimation models, the results indicate that most important independent variable is “AADT”, and “geometric design” (lane width and access control) and “pavement condition” (friction, serviceability index, and pavement type) are also important variables (Karlaftis and Golias, 2002). Our research proposes to statistically test such claims of a relationship between incident number and road quality, while controlling for traffic data (AADT and percent truck), segment length, crash conditions (date, road characteristics, and road surface), and pavement type. To investigate the relationship, we combine data from various sources. We then conduct a statistical analysis for ascertaining the effects of good road quality on incident number and severity. This paper de- scribes the data, methods, hypotheses, and results in turn.Item Effectiveness of Variable Message Signs Using Empirical Loop Detector Data(2003) Levinson, David M; Huo, HongThe effectiveness of Variable Messages Signs (VMS) on route guidance is assessed by a discrete probit choice model that estimates the proportion of vehicles that diverts to an alternative routes given the characteristics of different messages. A before-and-after study is also conducted to quantitatively evaluate the network wide reduction of travel time and total delay of VMS systems. We find that VMS has no obvious effect on reduction of travel time, but can reduce the total delay.Item An empirical study of the deviation between actual and shortest travel time paths(2015) Tang, Wenyun; Levinson, David, MFew empirical studies of revealed route characteristics have been reported in the literature. This study challenges the widely applied shortest path assumption by evaluating routes followed by residents of the Minneapolis - St. Paul metropolitan area, as measured by the GPS Component of the 2011 Twin Cities Travel Behavior Inventory. It finds that most travelers used paths longer than the shortest path. Some reasons for this are conjectured.Item Evaluating the "Safety In Numbers" Effect With Estimated Pedestrian Activity(2015) Murphy, Brendan; Levinson, David M; Owen, AndrewPedestrian and bicyclist collision risk assessment offers a powerful and informative tool in urban planning applications, and can greatly serve to inform proper placement of improvements and treatment projects. However, sufficiently detailed data regarding pedestrian and bicycle activity are not readily available for many urban areas, and thus the activity levels and collision risk levels must be estimated. This study builds upon other current work by the authors regarding pedestrian and bicycle activity estimation based on centrality and accessibility metrics, and extends the analysis techniques to estimation of pedestrian collision risk. The Safety In Numbers phenomenon, which refers to the observable effect that pedestrians become safer when there are more pedestrians present in a given area, i.e. that the individual per-pedestrian risk of a collision decreases with additional pedestrians, is a readily observed phenomenon that has been studied previously. The effect is investigated and observed in acquired traffic data, as well as estimated data, in Minneapolis, Minnesota.Item Factors Associated with the Gender Gap in Bicycling Over Time(2014) Schoner, Jessica; Lindsey, Greg; Levinson, David MBicycling has grown in popularity over the past decade, but the gap in rates of bicycling between men and women in the United States (US) persists. This paper uses regional travel behavior study data from the Minneapolis-St. Paul Metropolitan Region in 2000 and 2010 to measure and model the gender gap in bicycling over time. Findings from a series of statistical tests show that in aggregate, women bike less than men, and that growth in bicycling has been slower for women than for men over the past decade. However, stratifying the sample shows that women who live with at least one other adult bicyclist participate in bicycling at an equal rate as men. Similarly, frequency of bicycle trips among people who participate in bicycling differed by gender only slightly in 2000, and not at all in 2010. Binary logistic modeling results show that several factors, such as age and trip purpose, are associated with different bicycling outcomes for men and women, but some commonly hypothesized explanations, such as having children, were declining in effect or altogether insignificant. These findings and conclusions are important for practice and research because understand- ing the nuances of the gender gap, such as the apparent gap in participation but not in frequency or the contagion effect of living with a cyclist, is essential for targeting programs effectively. This paper also identifies several travel behavior data collection limitations that complicate studying the gender gap, and offers recommendations for further study.
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