Spatial context and the complexity of daily travel patterns: an international comparison

The analysis of travel patterns is an important research topic in transportation research and urban planning. It provides the background information necessary to better understand the complex relationship between urban structure, the transportation system and household travel patterns. To what extent do travel behaviour reflect the properties of the urban structure and the transportation network, or do these patterns largely follow their own regularities? Can different patterns be observed across different space-time settings, or can common patterns be observed, largely independent from such contexts? To better understand these relationships, this paper reports on some of the findings of analyses, conducted to identify underlying structures in various aspects of travel patterns. Travel patterns, derived from activity and travel diary data collected in Portland (USA), Midlands (UK), Fukuoka (Japan), Canadian metropolitan areas, and the South-Rotterdam region (The Netherlands) are compared. The results indicate that travel patterns are largely independent from spatial setting, except for some extreme cases.     

Are we keeping up? Accessibility,equity and air quality in regional planning

Many US metropolitan areas have undergone dramatic shifts in socioeconomic organization.. As urban areas gentrify, many low-income residents and communities of color have transitioned towards the exurban periphery. These suburban neighborhoods tend to have fewer employment opportunities and are fairly disconnected from public transportation networks serving the urban core. Using regional transportation plans (RTPs) for three California MPOs, we show that the transportation accessibility and environmental health issues affecting these exurban communities are unique and inadequately captured by the MPOs' current equity metrics. MPOs performance evaluation is regional and achieving equity within the urban core communities will not address emerging equity, accessibility and air quality concerns for exurban communities. With a brief history and a focused case study of RTPs for the San Francisco Bay Area, San Diego, and Fresno, we examine how air pollution, equity, and transportation interact in three different types of 21st century cities. We find that when allocating limited transportation funds, California metropolitan planning organizations (MPOs) prioritize the improvement of existing public transportation in urban core areas over expansion of transit networks towards disconnected exurbs. This approach is an effective way to reduce vehicle miles traveled (and thus, air pollution) at the regional level due to high population concentrations in urban cores. However, this approach also concentrates the air quality benefits of VMT reduction in these same urban core areas. Exurban residents' on-road and near-road exposure to Traffic-Related Air Pollution (TRAP) will not be reduced by improving public transit within the urban core. We argue that although these suburban and exurban communities are a small percentage of the regional population, they have a right to share in the benefits of transportation investments, particularly given the historical and ongoing patterns of displacement and economic exclusion from urban core areas.     

Urban spatial structure,employment subcenters,and freight travel

Metropolitan areas in the U.S. have become increasingly polycentric. Large employment subcenters have emerged outside of central cities, competing against the traditional city center for labor and businesses. The existing literature on land use and transportation focuses on passenger travel, providing little insight into the impact of polycentric metropolitan development patterns on freight activity. In this study, we use the Los Angeles region as a case study to examine the relationship between urban spatial development patterns and freight travel. Using the National Employment Time Series (NETS) data, we identify employment subcenters in metropolitan Los Angeles. We characterize freight activities associated with the subcenters using data from the Southern California Association of Governments (SCAG). We develop a regression model that estimates freight activity as a function of geographic characteristics, such as whether a location is in an employment subcenter, measures of nearby employment, access to the highway network, and proximity to intermodal freight facilities. The results indicate that employment is an important driver of freight activity; however, employment subcenters have an independent effect on freight activity. The results of this study suggest that further research on urban spatial structure and freight activity should assess the effects of employment subcenters and how their particular employment composition and characteristics are associated with freight activities at the metropolitan level. Such an approach would lead to more precise policy recommendations for urban goods movement.     

A comparative study of driving performance in metropolitan regions using large-scale vehicle trajectory data: Implications for sustainable cities

Volatile driving, characterized by hard accelerations and braking, can contribute substantially to higher energy consumption, tailpipe emissions, and crash risks. Drivers’ decisions to maintain speed, accelerate, brake rapidly, or jerk their vehicle are largely constrained by their unique regional and metropolitan contexts. These contexts may be characterized by their geography, roadway structure, traffic management, driving population, etc. This study captures how people generally drive in a region using large-scale vehicle trajectory data, implying how energy is consumed and how emissions are produced in regional transportation systems. Specifically, driving performance in four U.S. metropolitan areas (Los Angeles, San Francisco, Sacramento, and Atlanta) is compared, taking advantage of large-scale behavioral data (78.7 million seconds of speed records), collected by in-vehicle global positioning systems (GPSs) as part of regional surveys. Comparative analysis shows significant regional differences in terms of volatile driving and time spent to accelerate, brake, and jerk the vehicle during daily trips. Correlates of higher volatility are also explored, e.g., battery electric vehicles show low volatility, as expected. This study proposes a novel way to compare regional driving performance by successfully turning GPS driving data into valuable knowledge that can be applied in practice by developing regional driving performance indices. The new indices can also be used to compare regional performance over time and to imply the levels of sustainability of regional transportation systems. This study contributes by proposing a way to extract useful information from large-scale driving data.     

Circuity in urban transit networks

This paper investigates the circuity of transit networks and examines auto mode share as a function of circuity and accessibility to better understand the performance of urban transit systems. We first survey transit circuity in the Minneapolis–St. Paul, Minnesota, region in detail, comparing auto and transit trips. This paper finds that circuity can help to explain mode choices of commuters. We then investigate thirty-five additional metropolitan areas in the United States. The results from these areas show that transit circuity exponentially declines as travel time increases. Moreover, we find that the circuity of transit networks is higher than that of road networks, illustrating how transit systems choose to expand their spatial coverage at the expense of directness and efficiency in public transportation networks. This paper performs a regression analysis that suggests the circuity of transportation networks can estimate transit accessibility, which helps to explain mode share.     

Spatial patterns of logistics facilities in Gothenburg,Sweden

In recent years, the location of logistics facilities, in particular with regard to “logistics sprawl,” has emerged as a topic in the literature that is, a process of spatial decentralisation of logistics facilities in large metropolitan areas. The aim of this paper is to look at logistics sprawl patterns in the Gothenburg metropolitan area, in the south-west of Sweden. Looking at a medium-size monocentric urban region that is also a major port gateway for the country, this study provides novel elements in the study of locational patterns of freight facilities in metropolitan areas. It also provides an opportunity to identify the role of freight in planning, land use and zoning policies. A literature review is carried out on the issues of freight and logistics facilities locational patterns. A quantitative analysis is proposed, using data from Swedish statistics about the number of establishments with a NACE code related to logistics, as well as an original method providing a “cleaned” and more comprehensive dataset. We look at data at two different scales, one metropolitan and one regional, for years 2000 and 2014, as to enable a comparative and diachronical analysis. Logistics sprawl is measured by the average distance of warehouses to their common centre of gravity. Finally, interviews with transport and logistics providers as well as real estate investors and public agencies in the region, add qualitative information on the relative importance of different location factors related to logistics facilities and the issues raised. Logistics sprawl in Gothenburg occurs in specific ways, and differently at the two geographical levels of analysis.     

An evaluation of logistics sprawl in Chicago and Phoenix

This paper evaluates whether or not there is a sprawling tendency to the spatial patterns of warehouse establishments in the Chicago and Phoenix metropolitan areas. The trend of warehouses to move away from the urban centers to more suburban and exurban areas is referred to as “Logistics Sprawl”. To measure sprawl, the barycenter of warehousing establishments was compared to the barycenter of all other industry establishments in the region between the years of 1998 and 2013 for Chicago; 1998 and 2015 for Phoenix. This shows that logistics sprawl is a behavior experienced by warehouses in the Chicago area, but not in the Phoenix area. This paper discusses if logistics sprawl is a national trend or a regional behavior by comparing these results to the previous case studies of the Atlanta, Los Angeles, and Seattle metropolitan areas.     

Impacts of two-scale urban form and their combined effects on commute modes in U.S. metropolitan areas

This study explores the relationship between urban form at the metropolitan and neighborhood scales and the percentages of four individual modes to commute. It then looks at the combined effects of urban forms at the metropolitan scale in metropolitan areas in the continental United States using multi-level regression models with interactive terms between urban forms. This study contains the percentages for four commute modes: percentage of the vehicle (VT), public transit (PT), biking (BI), and walking (WK). As urban form factors, this study contains urban fragments, population density, job-resident balance (JRB), the percentage of green areas at the metropolitan scale, and distance to the nearest job center at the neighborhood scale. The results show that at the neighborhood scale, a farther distance from individual neighborhoods to the nearest job center is associated with higher VT, and lower PT, BI, and WK. At the metropolitan scale, urban form factors have a more significant association with the percentage of individual modes to commute in large MSAs compared with small MSAs in terms of population. Most urban form factors at the metropolitan scale are not independently associated with the use of commute modes, but their interactions are associated with the percentage of individual modes to commute. Particularly, the level of urban fragments and the percentage of green areas may transform the impact of high population density and JRB on the percentage of the individual modes to commute except for WK. This study provides planners and policymakers with important guidelines to establish combined urban form plans rather than single urban form oriented plans to reduce vehicle travel.     

Why do warehouses decentralize more in certain metropolitan areas?

Over the last decade, warehousing and distribution centers have decentralized to the urban peripheries where land is cheaper and readily available. This change in location patterns has been driven by the demand to build more modernized and larger facilities to accommodate an ever-increasing influx of freight. Since efficient freight movement is essential for the smooth functioning of metropolitan areas, decentralization should occur everywhere. However, this is not necessarily true. It is hypothesized that depending on the volume of goods movement and the spatial distribution of land prices, the extent of decentralization varies across metropolitan areas. This hypothesis is tested using 48 US metropolitan areas. Results provide robust evidence that high land prices push large warehouses away from central locations. When freight demand and land prices are not as high, the effect becomes insignificant. Indeed, not only is decentralization linked with large metro areas but also with very large warehouses.     

Continuity and change in American urban freeway networks

The American Interstate Highway System was created in 1944, though construction did not commence until 1956. During the planning process for this network the blueprint for American urban freeway systems was set in 1955 by a federal document called the Yellow Book. This provided about 100 maps of cities with planned urban freeway locations for the Interstate Highway System. A set of three basic network patterns were applied to these cities based on their size and location. In the half century since 1955 urban freeways in the Interstate System have expanded from a planned 2000 miles to over 16,600 miles, along with another 11,500 miles of non-Interstate freeways. The number of large metropolitan areas has increased tremendously while the monocentric commuting patterns of have been transformed. This paper explores how these urban freeway systems were applied to the country's urban geography of the 1950s and how they have adapted to changing populations and other transformations in American metropolitan areas in the last half century.     

Dynamic linkages between tourism transportation expenditures,carbon dioxide emission,energy consumption and growth factors: evidence from the transition economies

Tourism transport profoundly affects economic growth, energy consumption and carbon dioxide emissions. This study is an attempt to examine the impact of international tourism transportation expenditures, energy demand, foreign direct investment inflows, trade openness and urban population on carbon dioxide emission and per capita income for the panel of 11 transition Economies, over the period of 1995–2013. The results show that per capita income escalates the carbon dioxide emission (CO₂), which deteriorates the natural environment. International tourism receipts and international tourism expenditures for travel items are associated with the intensifying CO₂ emission and per capita income in the region. The study confirmed the energy-led emissions, FDI-led emissions, FDI-led growth, income-led emissions, income-led energy demand, trade-led growth and trade-led energy demand. The causality results further substantiate the the tourism-led growth and FDI hypothesis in the region. Finally, the variance decomposition analysis confirmed the following results, that is, (i) per capita income is the contributor that least influences CO₂ emissions, (ii) urban population influences per capita income and (iii) international tourism transportation expenditures will influence CO₂ emissions and per capita income for the next 10-year period.     

Multi-scale and multi-modal GIS-T data model

The role of urban transportation becomes increasingly important with the change of demographic and economic patterns. The trend to expect better urban living standards for inhabitants has significantly increased the demand for efficient and sustainable multi-modal transportation systems in large urban areas. This should favour emergence of balanced transportation system that uses each mode for what it does best. But still, the development of urban transportation policies partly relies on the availability of appropriate data and information. The research presented in this paper proposes a multi-modal and multi-scale GIS-T data model. The model introduced takes into account different transportation modes and integrates them within an integrated data model designed using an object-oriented approach. The model allows the development of specialised services designed after a survey and study of users’ and planners’ requirements. The approach is applied in a district of the city of Guangzhou and validated by a prototype development. This experimental system enables transportation planners and decision-makers to take better decisions effectively, and provides high-quality geospatial information-based services to final end-users.     

A GIS-based spatial statistical approach to modeling job accessibility by transportation mode: case study of Columbus,Ohio

Improving job accessibility based on transport connectivity helps to address equity issues. Spatial autocorrelation (SA) is also a focus of interest in transportation planning, but has been neglected in analyzing job accessibility in metropolitan areas. In this study, GIS-based job accessibilities by walking, transit, and car are computed for the metropolitan area of Columbus, Ohio, and three transport-based spatial autoregressive (SAR) models are estimated to account for the SA of job accessibility among neighboring block groups, while controlling for built-environment and socioeconomic factors. SA intensities and extents are compared in order to better understand local spatial clusters of job accessibility across the region. Direct and indirect spillover effects due to an investment change in transportation facilities are estimated and provide important transportation planning information. The results also show that walking-accessed jobs are primarily related to physical settings (e.g., land uses) at the local level. Locations with a higher share of zero-vehicle housing units have better job accessibility by transit. There is a spatial mismatch between Asian population clusters and transit-accessed jobs, possibly because of the car-oriented residential clusters around Honda of America Manufacturing in suburban areas. More importantly, locations with a higher share of single-parent households are at a disadvantage in overall job accessibility. Due to its complex transportation needs, a society friendly to single parents should spatially integrate accessible jobs with other needed activities via land-use and transportation planning. Alternatively, car-ownership programs and non-spatial social supports also might be effective to help secure job opportunities and perform daily life activities.     

Road accessibility and articulation of metropolitan spatial structures: the case of Madrid (Spain)

In the last few decades, rapid growth in mobility has facilitated the inclusion of distant places in metropolitan processes and the modification of traditional metropolitan areas into Polycentric Urban Regions. This paper aims to understand the articulation of metropolitan urban regions through a diachronic road network accessibility analysis with a focus on the Madrid Metropolitan Region (Spain) over a period of general increase in accessibility. The findings reveal that the metropolitan core has been reinforced and that its influence area has expanded. However, the main contribution of this work is the proposal of a methodological approach to identify city-profiles among the sub-centres organising the emerging polycentric urban structures.     

School commuting: the relationship between energy consumption and urban form

A large amount of research in the past has focused on the relationships between the energy consumption for home-to-work travel and land-use patterns. However, little is known about children’s mobility. This paper analyses the energy consumption, travel distances and mode choices for school commuting based on two decennial surveys in Belgium. The results highlight the following: (1) mobility behaviours have evolved drastically over the past decades for school commuting, an evolution that cannot be entirely related to land-use variables, (2) the energy consumption for school commuting is strongly dependent upon the school level, and (3) the links between land-use patterns and energy consumption for school commuting are different than those highlighted within the literature between urban forms and home-to-work commutes. The concentration of secondary schools and tertiary institutions in urban centres induces higher energy consumption rates, whereas the decentralisation of nursery and primary schools across the entire territory leads to very low local energy consumption and increased walking and cycling. These results provide a better understanding of school commuting within the European context and could guide future policies focused on transport energy consumption at the local scale.     

Understanding senior's daily mobility patterns in California using human mobility motifs

Population ageing has been a thorny issue in many countries. One of the challenges is how to improve and change transportation design and transport policy development to adapt to the dramatic changes in the composition of our population. In this paper, we apply a network-based approach of human mobility measurement called “motif” to investigate the distinct patterns in daily travel for seniors (age 60 and above) in California using the 2017 National Household Travel Survey (California-NHTS) data. Motifs are networks of distinct locations visited in a day and the directional movements between them. Using patterns of motifs, we correlate the diverse daily mobility patterns with socio-demographic characteristics as well as built environment factors. We find that 15 distinct motifs can capture approximately 82% and 86% of the total senior respondents on workdays and non-workdays, respectively. Seniors are more likely to have simple motifs with three or fewer distinct locations on non-workdays, while they present more complex motifs during workdays. Given 65% of the included seniors are retired, a large number of seniors present diverse and complex daily mobility patterns instead of staying at home all day. In addition, given the similarity between the urban core, urban district, and urban neighborhood in function and spatial proximity, there is significant heterogeneity in the daily mobility patterns among seniors living in these areas. Furthermore, we find that seniors living in areas with higher percentages of single-family housing units are most likely to stay at home on workdays.     

Modeling different penetration rates of eco-driving in urban areas: Impacts on traffic flow and emissions

Climate change and air quality are two main environmental challenges in metropolitan areas. As road transportation is one of the main contributors, public administrations are facing these problems with a number of complementary policy measures: shift to cleaner modes, new fuels and vehicle technologies, demand management, and the use of information and communication technologies (ICT) applied to transportation. Eco-driving is one of the measures that present large fuel savings at individual level. Although these savings are well documented in the literature, few studies focus on how eco-drivers driving patterns affect the surrounding vehicles and the traffic in general, and more particularly what would be the impact when the number of eco-drivers grows. Using a traffic microsimulation tool, four models in urban context have been built, corresponding to the different types of urban roads. Both the base-case and the parameters setting to simulate eco-driving have been calibrated with real data collected through floating vehicles performing the trips with normal and eco behaviors. In total, 72 scenarios were simulated, varying the type of road, traffic demand, and the percentage of eco-drivers. Then, the CO₂ and NO_x emissions have been estimated through a microscopic emission model. The results show that in scenarios with low or medium demand levels and increasing number of eco-drivers, the effects are positive in terms of emissions. On the other side, with high percentage of eco-drivers and high traffic demand, the emissions rise. Higher headways and smooth acceleration and decelerations increase congestion, producing higher emissions globally.     

Measuring cycling accessibility in metropolitan areas

Different measures of cycling accessibility have been widely introduced in transportation planning. However, those measurements are mainly restricted by the availability of travel behavior data. In addition, there has been limited comprehensive research on the importance of cycling accessibility to destinations based on the travel time or distance. In this paper, a new index for measuring bikeability in metropolitan areas is introduced. A Cycling Accessibility Index (CAI) is developed for quantifying cycling accessibility within local areas in metropolitan Melbourne, Australia. CAI is defined according to gravity-based measures of accessibility. This index measures cycling accessibility levels in terms of diversity of different land uses, number of activities in statistical areas, and the travel impedance between origins and destinations. The Victorian Integrated Survey of Travel and Activity (VISTA) dataset was used to evaluate the index and investigate the association between the cycling accessibility levels and the number of bicycle trips in local areas. The index is assessed by investigating the association between levels of cycling accessibility and the number of bicycle trips in statistical areas. Key findings indicate that there is a significant positive association between bike trips and the CAI.     

Metropolitan transportation planning in the 1990s: comparisons and contrasts in New Zealand,Chile and California

This article reviews major events and trends in metropolitan transportation planning and policy during the 1990s in three divergent Pacific rim jurisdictions: New Zealand, Chile, and California. Major metropolitan areas in each country have seen rising motorization, increasing congestion, and privatization of transportation services. Devolution of transportation planning responsibility has occurred; to a lesser degree, funding responsibility has been devolved from central to regional/local government. New Zealand pushed privatization harder in the 1990s than either Chile or California. While no dominant model of transportation planning has emerged, metropolitan-level planning has become more prominent and autonomous in each country studied.     

Urban sprawl and travel to work: the case of the metropolitan area of Madrid

The relationships between urban sprawl and journey to work in the metropolitan area of Madrid are analysed. Three elements of urban sprawl are addressed (metropolitan expansion, low-density and work and leisure facilities in suburban areas) and are related to the main characteristics of mobility (flow networks, mode-choice, and travel times). The conclusion reached is that the elements defining the new metropolitan morphology are related to an unsustainable mobility model, which increases commuter numbers, distances, and car use.