Flow Travel Research Articles

Measuring and Analysing Domestic Tourism: The Importance of an Origin and Destination Matrix

In this study, using the Spanish domestic and outbound tourism survey FAMILITUR, an inter-regional tourism flows analysis is carried out for the period 2004–2008. The degree of concentration of origin–destination trips is calculated in order to obtain the market share of the distribution of regional trips. An intra-regional perspective is also presented to confirm other divergences in terms of the region's capacity of attraction for its own residents. Finally, a ‘gravity’ model of domestic travel flows between the 17 Spanish autonomous communities is estimated to characterize the variables that affect Spaniards' tourism flows.

A cointegration analysis of bilateral air travel flows: The case of international travel to and from the United States

Demand for international air travel has risen over the past decade causing international visitation to the US to reach a record high in 2012. This paper assesses the dynamic impacts of GDP, exchange rate, and the 9/11 terrorist attacks on bilateral air travel flows between the US and its 11 major travel and trading partners. An autoregressive distributed lag modeling approach is employed to estimate short- and long-run relationships between variables. Long-run results demonstrate foreign GDP as the major determinant of demand for inbound travel to the US and US GDP is a crucial factor affecting demand for outbound travel from the US. These findings support a strong linkage between economic growth and demand for international air travel. The real exchange rate has relatively little impact on the bilateral air travel flows. The US dollar appreciation against foreign currencies is found to reduce demand for inbound travel to the US, while having mixed effects on outbound travel from the US. In the short-run, economic growth tends to be a primary factor influencing international travel flows to and from the US. The 9/11 market shock has a detrimental short- and long-run effect on the bilateral air travel flows, implying that the impact of 9/11 is prolonged in international air travel markets.

Walking in the City of Signs: Tracking Pedestrians in Glasgow

This paper aims to determine the way in which materialities within the environment influence pedestrians’ movements when searching for signs. The use of mobile methods to observe and track human interactions with the signs in a city contributes to the empirical data collection on everyday life practices of this study. This article presents the findings from non-participatory observations conducted in Glasgow. The observations took place in a selected area to explore the natural behavior of pedestrians in urban spaces when searching for signs. Random pedestrians were “unobtrusively” followed to investigate their natural pattern behavior when choreographing their travel flow. This study helps to determine the advantages and disadvantages of mobile methods for investigating the relationship between pedestrians, materials and the environment. The interdisciplinary approach developed in this article presents new perspectives on the way mobility and geosemiotics could contribute both theoretically and empirically with new knowledge in design practices.

Implications for the NHS of inward and outward medical tourism: a policy and economic analysis using literature review and mixed-methods approaches

BackgroundThe study examined the implications of inward and outward flows of private patients for the NHS across a range of specialties and services.ObjectivesTo generate a comprehensive documentary review; to better understand information, marketing and advertising practices; examine the magnitude and economic and health-related consequences of travel; understand decision-making frames and assessments of risk; understand treatment experience; elicit the perspectives of key stakeholder groups; and map out medical tourism development within the UK.Design and participantsThe study integrated policy analysis, desk-based work, economic analysis to estimate preliminary costs, savings and NHS revenue, and treatment case studies. The case studies involved synthesising data sources around bariatric, fertility, cosmetic, dental and diaspora examples. Overall, we drew on a mixed-methods approach of qualitative and quantitative data collection. The study was underpinned by a systematic overview and a legal and policy review. In-depth interviews were carried out with those representing professional associations, those with clinical interests and representative bodies (n = 16); businesses and employees within medical tourism (n = 18); NHS managers (n = 23); and overseas providers. We spoke to outward medical travellers (46 people across four treatment case studies: bariatric, fertility, dental and cosmetic) and also 31 individuals from UK-resident Somali and Gujarati populations.ResultsThe study found that the past decade has seen an increase in both inward and outward medical travel. Europe is both a key source of travellers to the UK and a destination for UK residents who travel for medical treatment. Inward travel often involves either expatriates or people from nations with historic ties to the UK. The economic implications of medical tourism for the NHS are not uniform. The medical tourism industry is almost entirely unregulated and this has potential risks for those travelling out of the UK. Existing information regarding medical tourism is variable and there is no authoritative and trustworthy single source of information. Those who travel for treatment are a heterogeneous group, with people of all ages spread across a range of sociodemographic groups. Medical tourists do not appear to inform their decision-making with hard information and consequently often do not consider all risks. They make use of extensive informal networks such as treatment-based or cultural groups. Motivations to travel are in line with the findings of other studies. Notably, cost is never a sole motivator and often not the primary motivation for seeking treatment abroad.LimitationsOne major limitation of the study was the abandonment of a survey of medical tourists. We sought to avoid an extremely small survey, which offers no real insight. Instead we redirected our resources to a deeper analysis of qualitative interviews, which proved remarkably fruitful. In a similar vein, the economic analysis proved more difficult and time consuming than anticipated. Data were incomplete and this inhibited the modelling of some important elements.ConclusionsIn 2010 at least 63,000 residents of the UK travelled abroad for medical treatment and at least 52,000 residents of foreign countries travelled to the UK for treatment. Inward referral and flows of international patients are shaped by clinical networks and longstanding relationships that are fostered between clinicians within sender countries and their NHS counterparts. Our research demonstrated a range of different models that providers market and by which patients travel to receive treatment. There are clearly legal uncertainties at the interface of these and clinical provision. Patients are now travelling to further or ‘new’ markets in medical tourism. Future research should: seek to better understand the medium- and long-term health and social outcomes of treatment for those who travel from the UK for medical treatment; generate more robust data that better capture the size and flows of medical travel; seek to better understand inward flows of medical travellers; gather a greater level of information on patients, including their origins, procedures and outcomes, to allow for the development of better economic costing; explore further the issues of clinical relationships and networks; and consider the importance of the NHS brand.FundingThe National Institute for Health Research Health Services and Delivery Research programme.

Exploring Bias in Traffic Data Aggregation Resulting from Transition of Traffic States

Transportation engineers and researchers heavily use traffic data, which are generally aggregated by predetermined time intervals (e.g., 5 to 15 min). The aggregation process often discards essential information of traffic state transition (e.g., breakdowns). However, the transition of traffic conditions within an aggregation interval is not well understood. This study explored traffic state transition from uncongested to congested regimes that occurred within a predetermined time interval. From two urban freeway locations in Norfolk, Virginia, traffic data archived at 15-min intervals were obtained. A heuristic method based on a Gaussian mixture model was developed to detect the aggregate traffic data that exhibit the transition of traffic states as well as to partition the data statistically into uncongested and congested traffic states. Results show a substantial difference in travel speed (approximately 20 mph) between the two states. In addition, these results illustrate that aggregating these different traffic conditions can cause substantial traffic data aggregation bias by lowering travel speed and flow rates, especially in high traffic flow situations. Finally, new insights into valid traffic data aggregation and speed–flow–concentration relationship development are discussed.

Recharge and discharge controls on groundwater travel times and flow paths to production wells for the Ammer catchment in southwestern Germany

Travel times and flow paths of groundwater from its recharge area to drinking-water production wells will govern how the quality of pumped groundwater responds to contaminations. Here, we studied the 180 km2 Ammer catchment in southwestern Germany, which is extensively used for groundwater production from a carbonate aquifer. Using a 3-D steady-state groundwater model, four alternative representations of discharge and recharge were systematically explored to understand their impact on groundwater travel times and flow paths. More specifically, two recharge maps obtained from different German hydrologic atlases and two plausible alternative discharge scenarios were tested: (1) groundwater flow across the entire streambed of the Ammer River and its main tributaries and (2) groundwater discharge via a few major springs feeding the Ammer River. For each of these scenarios, the groundwater model was first calibrated against water levels, and subsequently travel times and flow paths were calculated for production wells using particle tracking methods. These computed travel times and flow paths were indirectly evaluated using additional data from the wells including measured concentrations of major ions and environmental tracers indicating groundwater age. Different recharge scenarios resulted in a comparable fit to observed water levels, and similar estimates of hydraulic conductivities, flow paths and travel times of groundwater to production wells. Travel times calculated for all scenarios had a plausible order of magnitude which were comparable to apparent groundwater ages modelled using environmental tracers. Scenario with groundwater discharge across the entire streambed of the Ammer River and its tributaries resulted in a better fit to water levels than scenario with discharge at a few springs only. In spite of the poorer fit to water levels, flow paths of groundwater from the latter scenario were more plausible, and these were supported by the observed major ion chemistry at the production wells. We concluded that data commonly used in groundwater modelling such as water levels and apparent groundwater ages may be insufficient to reliably delineate capture zones of wells. Hydrogeochemical information relating only indirectly to groundwater flow such as the major ion chemistry of water sampled at the wells can substantially improve our understanding of the source areas of recharge for production wells.

Bayesian Dynamic Linear Model with Switching for Real-Time Short-Term Freeway Travel Time Prediction with License Plate Recognition Data

AbstractThis paper presents a Bayesian inference-based dynamic linear model (DLM) with switching based on three-phase traffic flow theory to predict online short-term travel time with plate recognition data. The proposed method combines the DLM model with a Hidden Markov Model (HMM) to capture the probability of flow breakdown and delays associated with congestion. By viewing travel time fluctuations as a time-varying stochastic process due to unforeseen events (e.g., incidents, accidents, or bad weather), the proposed dynamic linear model with Markov switching (SDLM) employs the HMM to determine the optimal traffic state sequence corresponding to a given travel time and flow rate observation sequence. The experimental results based on automatic license plate recognition data of a Jingtong Expressway stretch in Beijing City suggest that the proposed method can provide accurate and reliable travel time prediction under various traffic conditions.

2차로도로 평균 통행속도-총지체율-교통량 관계 곡선 재정립

PURPOSES : Two-lane highways have one lane in each direction, and lane changing and passing maneuvers take place in the opposing lane depending on the availability of passing sight distance. 2001 Korea Highway Capacity Manual (KHCM) is classified into two classes of two-lane highways (Type I, II), and average travel speed and time-delayed rate are used as measures of effectiveness (MOEs). However, since existing two-lane highways have both uninterrupted and interrupted traffic flow-system elements, a variety of free-flow speeds exhibits in two-lane highways. In addition, it is necessary to check if the linear-relationship between volumes and time-delayed rate is appropriate. Then, this study is to reestablish the relationship between average travel speed, time-delayed rate, and flow. METHODS : TWOPAS model was selected to conduct this study, and the free-flow speeds of passenger cars and the percentage of following vehicles observed in two-lane highways were applied to the model as the input. The revised relationships were developed from the computer simulation. RESULTS : In the revised average travel speed vs. flow relationship, the free-flow speed of 90km/h and 70km/h were added. It shows that the relationship between time delayed-rate and flow appeared to be appropriate with the log-function form and that there was no difference in time-delayed rate between the free flow speeds. In addition to revise the relationships, the speed prediction model and the time-delayed rate prediction model were also developed. CONCLUSIONS : The revised relationships between average travel speed, time-delayed rate, and flow would be useful in estimating the Level of Service(LOS) of a two-lane highway.

Modeling of coastal erosion and sediment deposition during the 2004 Indian Ocean tsunami in Lhok Nga, Sumatra, Indonesia

This study presents the results of numerical simulations of the 2004 Indian Ocean earthquake and tsunami in the Bay of Lhok Nga (northwestern coast of Sumatra, Indonesia) integrating sediment erosion and deposition. We investigate the transport of sediment both by suspension and by bedload under different scenarii of long breaking dispersive waves through a series of numerical experiments. The earthquake source model used by Koshimura et al. (Coast Eng J 51:243–273, 2008) with a 25-m dislocation better reproduces the wave travel time, flow depth and inundation area than the other models tested. The model reproduces realistically the pronounced coastal retreat in the northern part of Lhok Nga Bay (retreat ranging between 50 and 150 m), where Paris et al. (Geomorphology 104:59–72, 2009) estimated a mean retreat of 80 m. There is also a good agreement between the simulated area of coastal retreat (195,400 m2) and the field observations (203,200 m2). The simulation may underestimate the volume of tsunami deposits (611,700 m3 vs. 500,000–1,000,000 m3 estimated by Paris et al. (2009). The model fully reproduces the observed thickness of tsunami deposits when considering both bedload and suspension, even if bedload transport dominates. Limitations are due to micro-scale topographic, anthropic features (which are not always represented by the DEM) and the amount of debris which may influence flow dynamics and sediment transport.

Climate change in a regional context: relative vulnerability in the Australasian skier market

The concept of relative vulnerability allows for comparisons between analogous units in a regional context. It is utilised within tourism studies to consider how climate change might affect demand and perceived attractiveness of destinations relative to their competitors. This paper examines Australian tourists travelling to New Zealand’s ski fields, responding to the intergovernmental panel on climate change (IPCC) assertion that, “tourist flows from Australia to New Zealand might grow as a result of the relatively poorer snow conditions in Australia” (Hennessy et al. 2007: p 523). This travel flow is not a new phenomenon; however, it is forecast to increase as climate change impacts upon Australia’s natural and man-made snowmaking capacity with implications for the viability of the ski industries in both Australia and New Zealand. The Queenstown Lakes Region (South Island, New Zealand) serves as the field area for this study. The empirical research utilises a qualitative methodology for which in-depth, semi-structured interviews were conducted with New Zealand ski industry representatives and Australian tourists during the southern hemisphere winter season of 2011. Findings suggest that the social context of vulnerability creates difficulty in forecasting the outcomes and behaviours associated with relative vulnerability. While tourism representatives’ focus on snow reliability and availability to conceptualise relative vulnerability, Australian tourists are influenced by a broader range of factors including their own travel experience. This paper demonstrates a clear need to move beyond a focus on snow reliability to consider the broad range of factors that contribute to regional variations in vulnerability. In doing so, it confirms the critical importance of situating relative vulnerability within a social context.

Transient analysis of fluctuations of electrical conductivity as tracer in the stream bed

Abstract. Spatial patterns of water flux in the stream bed are controlled by the distribution of hydraulic conductivity, bedform-induced head gradients and the connectivity to the adjoining groundwater system. The water fluxes vary over time driven by short-term flood events or seasonal variations in stream flow and groundwater level. Variations of electrical conductivity (EC) are used as a natural tracer to detect transient travel times and flow velocities in an in-stream gravel bar. We present a method to estimate travel times between the stream and measuring locations in the gravel bar by non-linearly matching the EC signals in the time domain. The amount of temporal distortion required to obtain the optimal matching is related to the travel time of the signal. Our analysis revealed that the travel times increase at higher stream flows because lateral head gradients across the gravel bar become significantly smaller at the time.

Stochastic Demand Dynamic Traffic Models Using Generalized Beta-Gaussian Bayesian Networks

A stochastic demand dynamic traffic model is presented to predict some traffic variables, such as link travel times, link flows, or link densities, and their time evolution in real networks. The model considers that the variables are generalized beta variables such that when they are marginally transformed to standard normal, they become multivariate normal. This gives sufficient degrees of freedom to reproduce (approximate) the considered variables at a discrete set of time-location pairs. Two options to learn the parameters of the model are provided-one based on previous observations of the same variables and one based on simulated data using existing dynamic models. The model is able to provide a point estimate, a confidence interval, or the density of the variable being predicted. To this end, a closed formula for the conditional future variable values (link travel times or flows), given the available past variable information, is provided. Since only local information is relevant to short-term link flow predictions, the model is applicable to very large networks. The following three examples of application are given: (1) the Nguyen-Dupuis network; (2) the Ciudad Real network; and (3) the Vermont state network. The resulting traffic predictions seem to be promising for real traffic networks and can be done in real time.

Modeling and solving continuous-time instantaneous dynamic user equilibria: A differential complementarity systems approach

This paper is the second of a two-part research wherein we undertake a mathematically rigorous investigation of the continuous-time dynamic user equilibrium (DUE) problem using the recently introduced mathematical paradigm of differential complementarity systems (DCSs). Based on the thorough study of continuous-time single-destination point-queue models in the previous part, we first extend this special case to multiple destinations respecting the First-In–First-Out property of travel flows. A DCS with constant time delay is then introduced to formulate the continuous-time model of instantaneous dynamic traffic equilibria (IDUE) with a fixed demand profile. We develop a time decomposition scheme based on link free flow travel times to convert the delay DCS to a series of DCSs without time delays that are solved by a numerical time-stepping method. We provide rigorous numerical treatment of the time-decomposed IDUE model, including solvability of the discrete-time complementarity problems and convergence of the numerical trajectories to a continuous-time solution. We present numerical results to validate the IDUE on a small network and also on the Sioux Falls network.

Signs in Place: Choreographing Travel Flow in Urban Spaces

Signs in Place: Choreographing Travel Flow in Urban Spaces

Flows of people, flows of ideas, and the inequality of nations

The present paper examines a neglected determinant of aggregate productivity: temporary cross-border flows of people. We hypothesize that interaction between people from different nations facilitates the international diffusion of ideas, thus stimulating aggregate productivity. In order to assess the causal impact of people flows on productivity, we construct an instrument for people flows. By analogy to the trade/growth literature, this instrument is derived from a fitted gravity equation involving geographic determinants of bilateral travel flows. Our cross-section analysis reveal that greater international interaction leads to higher productivity; a very similar result, qualitatively as well as quantitatively, is obtained when we employ dynamic panel data methods for the purpose of identification.

The development of the Gulf region’s air transport networks – The first century

This paper employs the concepts of centrality, intermediacy and proximity to explain the evolution of air transport networks in Asia and applies them to the region surrounding the Arabian Gulf. In doing so the paper provides a structured, historical account of the development of air transport in a region that occupied a central place for important trade routes for thousands of years. The paper argues that there has been a “principal axis shift” so that the role of the region is no longer defined as an intermediate section of the east-west routes. Indeed, the region has come to re-occupy a central place in trade and travel flows serving a fundamentally changed global aviation network building upon the economic and social development within the region.

Paying the pilot? The economics of subsidising international air travel to small remote island nations with large diaspora

The tourism-air transport linkage may be complicated by the presence of substantial non-tourist leisure travel flows. This paper analyses the value of direct long-haul air service to Los Angeles for two small South Pacific nations, Tonga and the Cook Islands, which were faced with demands that they subsidise the current service to ensure its continuation. Both countries are tourist destinations, but both also have sizeable diaspora of economic emigrants living abroad, which generate considerable visiting friends and relatives traffic. It turns out that the economics of this travel are quite different from those relating to foreign tourism, such that it is possible that Tonga could actually lose by having the long-haul service. The bottom line is that the Cook Islands do gain, and that Tonga probably does, though in both cases by less than the amount of subsidies that they agreed to pay the airline.

A Review of Information Dissemination Protocols for Vehicular Ad Hoc Networks

With the fast development in ad hoc wireless communications and vehicular technology, it is foreseeable that, in the near future, traffic information will be collected and disseminated in real-time by mobile sensors instead of fixed sensors used in the current infrastructure-based traffic information systems. A distributed network of vehicles such as a vehicular ad hoc network (VANET) can easily turn into an infrastructure-less self-organizing traffic information system, where any vehicle can participate in collecting and reporting useful traffic information such as section travel time, flow rate, and density. Disseminating traffic information relies on broadcasting protocols. Recently, there have been a significant number of broadcasting protocols for VANETs reported in the literature. In this paper, we classify and provide an in-depth review of these protocols.

Sign Visibility for Pedestrians Assessed with Agent-Based Simulation

As cities and urban centers become bigger and as building spaces become larger, the need for correctly designed and located signage becomes paramount. The geometry of these urban or architectural spaces is becoming more complex because of traffic flow in multiple directions, several obstructions, and nonconvex spaces. The complex architecture makes the determination of the optimal locations for the placement of signs in these spaces more difficult. This paper provides a framework for the rational location of signs in public spaces to increase their detectability through the consideration of the geometric configuration of the space, the occupant or pedestrian travel flow patterns, the locations of obstructions, the legibility distance, and the sign design. The framework used an agent-based simulation model, in which occupants or pedestrians were modeled as intelligent agents that moved in the space according to predefined traffic patterns. The social force model was used to simulate the microscopic movement behavior of the agents in the space. In addition, the perceptual attention of the pedestrians was modeled by consideration of the field of view of the agents as well as sign location and design. A computer simulation model was developed and tested in a real-life case study to demonstrate the applicability of the model. The research presented here should be of interest to practicing architects and engineers as well as researchers.

Deaths of cyclists in London: trends from 1992 to 2006.

BackgroundCycling is an increasingly important mode of transport for environmental and health reasons. Cycling fatalities in London were previously investigated in 1994 using routinely collected data. Since then, there have been shifts in the modes of transport used, and in transport policies. We sought to replicate the previous work using data on cyclist deaths in London between 1992 and 2006, specifically investigating whether heavy goods vehicles continued to pose a threat.MethodsObservational study based on analysis of time series of police road casualties data, 1992 to 2006, in London, UK. The main outcome measures were cyclists killed in road traffic collisions. Poisson regression and chi-squared test for homogeneity were used to assess time effects. Travel flow data was then used to estimate annual fatality rates per 100,000 cyclists per kilometre.ResultsFrom 1992 to 2006 there was a mean of 16 cycling fatalities per year (range 8-21). 146 deaths (60%) were in inner London and 96 in outer London. There was no evidence for a decline over time (p = 0.7) other than a pronounced dip in 2004 when there were 8 fatalities. Freight vehicles were involved in 103 of 242 (43%) of all incidents and the vehicle was making a left turn in over half of these (53%). The fatality rate ranged from 20.5 deaths in 1992 to 11.1 deaths in 2006 per 100,000 estimated cyclists per kilometre (rate ratio 0.54, 95% confidence interval 0.28 to 1.03).ConclusionsThere is little evidence fatality rates have fallen. Freight vehicles over 3.5 tonnes continue to present a disproportionate threat; they should be removed from urban roads and more appropriate means of delivery of essential goods found.