Kilometer Of Travel Research Articles

An international urban air pollution model for the transportation sector

Analysis of cities across the globe illustrates a strong relationship between vehicle kilometres of travel (VKT) and urbanised land area. As VKT can be used as a surrogate for vehicular emissions, this provides a method of estimating urban vehicular pollution. These emission rates are incorporated with simple meteorological forcing into a box model to provide a generalised urban air pollution model for transportation within any city and validated against published data. The results suggest direct air pollution benefits from minimising the outward growth of cities, and add weight to urban policies that emphasise compact city planning principles.

City Structure and Journey-to-work Travel Behaviour

Traffic generated from residential land uses and traffic attracted to employment zones contributes the most to person kilometers of travel. The fundamental importance of the average length of commuting trips as a measure of sustainability is widely recognized by researchers. The urban consolidation, proportion wasteful and travel performance efficiency index have been defined as a performance indicator based on the relationship between the actual mean journey-to-work trip length, minimum and maximum trip length given the spatial distribution of homes and workplaces. These indexes are tested with data for Sapporo, Asahikawa, Hakodate and Kushiro in Hokkaido.

Land-Use and Travel Behaviour. A Survey of Some Analysis and Policy Perspectives

This paper discusses interactions between land-use and travel behaviour in the light of recent developments on the policy arena, in particular the increasing emphasis on sustainable development of urban and regional systems. Schemes for integrated analyses of land-use and transport and for comparing urban structures in terms of land-use dispersion and travel behaviour are presented. The new national transport policy of Sweden has a strong emphasis on environmental and safety objectives. However, increasing vehicle kilometres of travel (VKT) and decreasing transit shares are characteristic for the projected development of Stockholm until the year 2030. Only very drastic integrated policies can reduce VKT to a level consistent with long-term environmental targets. Land-use policies play a small role in this context. A transit-oriented settlement structure on the sub-regional scale tends to be more important than increased density on the regional scale. Compact cities and local jobhousing balance may provide the potential for sustainable transport behaviour, but other policies and strong incentives are needed to reverse current urban development trends. With current trends other urban forms (e.g. “decentralised concentration” or “corridor development”) are likely to be more efficient in terms of VKT.

Contrasting Time-Based and Distance-Based Measures for Quantifying Traffic Congestion Levels: Analysis of New Jersey Counties

Various approaches for quantifying congestion and how these different measures affect the perception of the problem are discussed. In a study done for the state of New Jersey, thresholds of the volume-capacity ratio on any given roadway were adopted to identify where congestion was occurring. The severity of this congestion was then analyzed by using both distance-based and time-based measures to describe the magnitude of the problems. It was found that the distance-based measures such as vehicle kilometers of travel indicated a relatively small amount of congestion to be present statewide. Time-based measures such as vehicle hours of travel in congestion revealed more severe problems, with more than half of total peak period travel time in many counties being spent in congested conditions. The time-based measures of congestion provided a stronger basis for more generalized conclusions. These measures indicated that much of the delay due to congestion in New Jersey could be attributed to the most severely congested locations in the state. These same time-based measures also strongly suggested that arterial roadways contribute far more to the overall congestion problem than previously reported. Time-based congestion measures provide a different perception on congestion, one in keeping with the common perception of the problem. Time-based congestion measures also provide stronger guidance on identifying major issues, enabling policy makers to better address problems within the state and solutions that are most likely to have the greatest impact.

Analysis of Aggregation Effects in Vehicular Emission Estimation

In the United States, most emissions modeling is done using the MOBILE suite of programs. One of the inputs required is vehicle kilometers of travel (VKT) for each vehicle class as a function of average speed. This information traditionally has been obtained from macroscopic planning models whereby the average speed on a given length of roadway is the same for all vehicle classes. During the past 10 years, however, there has been a definite shift away from macro-level transportation modeling to a more simulation-based approach. In addition to the advances in modeling techniques, the advent of intelligent transportation systems (ITS) has opened numerous possibilities for capturing detailed transportation-related information. The purpose of this paper is to illustrate the trade-offs involved under different aggregation scenarios for estimating vehicular emissions using data sets produced by microsimulation models and ITS. A 22-km section of Interstate 10 in Houston, Texas, was used as the test bed in this study. The VKT and speed data for this corridor were determined using a calibrated TRANSIMS model. This information was then used with the MOBILE5a emission model to compute emission estimates. The vehicular emissions were determined for a broad range of spatial, temporal, and combined spatial and temporal levels of disaggregation. It was found that emission estimates could vary by as much as 20 percent, depending on how the VKT and speed data are determined or depending on the type of ITS data-collection technology used.

Optimisation of parking guidance and information systems display configurations

Operators of parking guidance and information (PGI) systems often have difficulty in determining the best car park availability information to present to drivers in periods of high demand. This paper describes a behavioural model of parking choice incorporating drivers perceptions of waiting times at car parks based on PGI signs. This model was used to predict the influence of PGI signs on the overall performance of the traffic system. Relationships were developed for estimating the arrival rates at car parks based on trip patterns, driver characteristics, car park attributes as well as the car park availability information displayed on PGI signs. Drivers' perceptions of waiting times at car parks were assumed to be influenced by the PGI signs for observers of the signs and actual car park utilisation levels for non-observers. The model assumes that the choice of car park does not change after entering the city centre, even if conditions observed are different from those initially perceived. A mathematical programme was formulated to determine the optimal display PGI sign configuration to minimise queue lengths and vehicle kilometres of travel (VKT). The model was limited to off-street parking choices and illegal parking was not incorporated. A simple genetic algorithm was used to identify solutions that significantly reduced queue lengths and VKT compared with existing practices. These procedures were applied to an existing PGI system operating in Tama New Town near Tokyo. Significant reductions in queue lengths and VKT were predicted using the optimisation model. This would reduce traffic congestion and lead to various environmental benefits.

Real-Time Indicators of Vehicle Kilometers of Travel and Congestion: One Year of Experience

Automated traffic data posted on the Internet by four cities have been continuously downloaded, processed, and archived for more than 1 year by an automated system developed by Oak Ridge National Laboratory and funded by the U.S. Bureau of Transportation Statistics. Although the experimental system is far from national in scale and scope, it has shown that automated collection and processing of local traffic data via the Internet for national purposes is feasible and practical. Strong seasonal patterns make it too early to estimate statistical models of traffic growth, but comparisons of the same months in 1998 and 1999 indicate changes ranging from 1 percent to 3 percent for the monitored systems. Direct measurements of delay on the monitored systems are lower than published estimates for previous years. Although some progress in the input of missing data has been made, missing data are still a major problem, and better methods are needed.

Vehicle Emission Unit Risk Factors for Transportation Risk Assessments*

When the transportation risk posed by shipments of hazardous chemical and radioactive materials is being assessed, it is necessary to evaluate therisks associated with both vehicle emissions and cargo‐related risks. Diesel exhaust and fugitive dust emissions from vehicles transporting hazardous shipments lead to increased air pollution, which increases the risk of latent fatalities in the affected population along the transport route. The estimated risk from these vehicle‐related sources can often be as large or larger than the estimated risk associated with the material being transported. In this paper, data from the U.S. Environmental Protection Agency's Motor Vehicle‐Related Air Toxics Study are first used to develop latent cancer fatality estimates per kilometer of travel in rural and urban areas forall diesel truck classes. These unit risk factors are based on studies investigating the carcinogenic nature of diesel exhaust. With the same methodology, the current per‐kilometer latent fatality risk factor used in transportation risk assessments for heavy diesel trucks in urban areas is revised and the analysis expanded to provide risk factors for rural areas and all diesel truck classes. These latter fatality estimates may include, but are not limited to, cancer fatalities and are based primarily on the most recent epidemiological data available on mortality rates associated with ambient air PM‐10 concentrations.

Estimating Vehicle Kilometers of Travel Using PPS Sampling Method

The estimation of vehicle kilometers of travel at various levels of a road network is one of the key tasks of any road and transport authority. This paper introduces a method to estimate the vehicle kilometers of travel. Stratified probability proportional to size (PPS) cluster sampling has been applied as a developmental tool in the kingdom of Morrocco. The PPS sampling is based on classical statistical theory. Using the PPS sampling together with stratified sampling, it is possible to optimally allocate counting resources so that an acceptable level of reliability can be obtained in different parts of the network. In addition, the costs of countings may be included as part of the optimization. The PPS method requires some historical data to weigh different clusters of the road network according to their importance. However, mechanical approaches based on statistical theory alone do not result in satisfactory solutions, but the counting system should also be evaluated taking into account technical, economical, and organizational factors.

Vehicle emission unit risk factors for transportation risk assessments.

When the transportation risk posed by shipments of hazardous chemical and radioactive materials is being assessed, it is necessary to evaluate the risks associated with both vehicle emissions and cargo-related risks. Diesel exhaust and fugitive dust emissions from vehicles transporting hazardous shipments lead to increased air pollution, which increases the risk of latent fatalities in the affected population along the transport route. The estimated risk from these vehicle-related sources can often be as large or larger than the estimated risk associated with the material being transported. In this paper, data from the U.S. Environmental Protection Agency's Motor Vehicle-Related Air Toxics Study are first used to develop latent cancer fatality estimates per kilometer of travel in rural and urban areas for all diesel truck classes. These unit risk factors are based on studies investigating the carcinogenic nature of diesel exhaust. With the same methodology, the current per-kilometer latent fatality risk factor used in transportation risk assessments for heavy diesel trucks in urban areas is revised and the analysis expanded to provide risk factors for rural areas and all diesel truck classes. These latter fatality estimates may include, but are not limited to, cancer fatalities and are based primarily on the most recent epidemiological data available on mortality rates associated with ambient air PM-10 concentrations.

Synergisms Among Land Use, Transit, and Travel Pricing Policies

A review of empirical studies of the effects of land use on travel behavior leads to the conclusion that increasing density and mix can decrease vehicle kilometers of travel. The authors’ research project for the U.S. Environmental Protection Agency is outlined. Descriptions of the travel model used in the first phase of this research and of the emissions model and the traveler welfare model used in the study are given. The authors describe the six scenarios evaluated to date and the results of the simulations for the year 2015 for travel, emissions, and traveler welfare.

Spatial Variations in Travel Behavior within Greater Toronto Area

Rapid suburbanization of housing and employment has produced severe traffic congestion in North American cities. One response to this problem in the greater Toronto area (GTA) has been to identify urban forms that are more supportive of public transport and require less vehicle kilometers of travel to support. The analytical tools used to assess the travel implications of different urban forms normally use travel demand parameters that are uniform across an area. This has yielded misleading estimates of travel demands. This paper describes analyses of the intraregional differences in travel behavior in the greater Toronto area. The analyses described are at two spatial scales: the suburb (municipality/planning district) level and the much finer traffic analysis zone level. The analysis units were grouped into high-growth, developing,a nd low-growth categories at both spatial scales. The analyses reported in this paper show that household characteristics and travel behavior are quite similar for both established and redeveloping zones in the older, stable suburbs. Significant differences in travel characteristics exist between the older, established zones and the growing zones in the developing suburbs. Household trip rates are shown to vary with household size, car ownership, and whether a household is located in a stable ormore » growing suburb. Accessibility to public transport is shown to affect trip behavior differently in growing areas than in established areas. The paper concludes by discussing the public policy and transport systems analysis implications of the results.« less

Road Traffic Violations and Seat Belt Use in Kuwait: Study of Driver Behavior in Motion

Despite heavy investments in the transportation infrastructure and the existence of a young vehicle fleet, road safety in the affluent State of Kuwait continues to decline. Poor driver behavior and lack of enforcement of traffic regulations are believed to be the main causes of the unsafe driving environment. The findings of a research project designed to examine the relationship between seat belt use and road traffic violations in Kuwait are reported. The traffic violation behavior of 821 randomly selected drivers was recorded while the drivers were followed to their destinations. Factors of nationality, age range, gender, roadway type, vehicle type, time of day, trip time, and trip distance were also monitored. The average sample nonuser of seat belts made more than twice as many violations both per kilometer of travel and per minute of trip time than did seat belt users. Seat belt nonusers and young drivers (especially Kuwaitis) were found to be overrepresented in the violating groups, and discriminant analysis successfully discriminated between the high and low violators of traffic rules.

Increasing job opportunities in a subregion for region-wide fuel conservation and air-quality improvement

Presently, there is much interest in defining urban development patterns for reducing energy consumption in transportation and in improving air quality. This research examined the effects of improving job opportunities in a subregion on region-wide transportation fuel consumption and emissions. A research framework, consisting of travel simulation models, and energy and emissions factors, was developed for testing land use – transportation scenarios. The travel simulation modelling framework consisted of the four-step approach, including the calibration of trip distribution and modal split models. Fuel consumption and emissions were estimated by using vehicle kilometres of travel. The city of Kanata within the Regional Municipality of Ottawa – Carleton, Canada, was used as a case study. Five scenarios illustrating possible future employment schemes were developed. Vehicle kilometres, fuel, and emissions for both automobile and public transit were estimated for year 2011 scenarios. The results are presented as totals for both the overall National Capital Area and for the subregion, Kanata. From these results, it is concluded that providing more job opportunities and enhancing the job to housing ratio in a satellite city could reduce fuel consumption and emissions from a regional perspective. Key words: air pollution, emissions, fuel consumption, land use, transportation modelling, simulation.

Estimating the Effect of Operational Improvements in the Houston Area

Measuring the effects of transportation system improvements has long been a challenge. Two estimates—the congestion index method and the travel delay method—are used to produce a range of possible benefits resulting from the implementation of transportation projects and programs. The congestion index method uses the roadway congestion index (RCI), and its relationship with congestion cost per capita, to estimate the benefit derived from operational improvements. The RCI provides an areawide assessment of congestion based on freeway and principal arterial street system daily vehicle kilometers of travel per lane kilometer data. The travel delay method calculates congestion cost by associating the value of time, cost of fuel, and cost of operating commercial vehicles with travel delay estimates. These two methods are used to estimate the effects of three types of transportation system improvement projects/programs—freeway traffic management system, high-occupancy vehicle lanes, and regional computerized traffic signal system— implemented on the freeway and principal arterial street system in Houston, Texas. Although only three operational projects/programs are discussed, it is possible to effectively evaluate the implementation of many other improvements using this methodology.

Development of detergent additives for automotive fuels in other countries

With increasing demands on environmental protection and with the production of reformulated unleaded motor fuels, new and effective detergent additives are urgently needed. A number of monographs and scientific works have been devoted to problems involved in the development and application of such additives. Since the mid-1980s in the United States and certain other countries, a crisis has been noted in the application of detergent additives. It has been found that certain types of detergents not only fail to give the required cleaning effect, but even promote the formation of deposits. This situation can be attributed primarily to the development of automotive gasoline engines with direct fuel injection. In the United States in 1989, about 90% of all automotive vehicles were equipped with such engines, which have very definite advantages in fuel economy, less smoking, and a number of other areas. However, after a few thousand kilometers of travel, the characteristics of these engines deteriorate, and undesirable changes are observed, including excessive fuel consumption, a reduction of the vehicle speed, and increased contents of carbon monoxide in the exhaust. These changes occur because of deposit formation in the fuel intake system, particularly on the intake valves. As the deposits continuemore » to accumulate, the engines gradually experience an increase in octane number demand for engine operation without knocking. This phenomenon, which is known in American publications as {open_quotes}octane requirement increase{close_quotes} or ORI (Russian initialism RTOCh, literal translation, {open_quotes}increase of requirements for octane number{close_quotes}), continues until a certain equilibrium octane number is reached. This equilibrium value may change, depending on the engine design and other factors. In all cases, however, the ORI of modern engines is significant, amount to 2-14 octane numbers.« less

A perspective on road fatalities in Jeddah, Saudi Arabia

The aim of this paper is to study an epidemiological aspect of fatalities from motor vehicle accidents in Jeddah, Saudi Arabia. All fatal accidents that occurred in Jeddah between 1 January and 31 December 1987 are analyzed. The death rates per hundred million vehicle kilometers of travel, per 100,000 registered motor vehicles, and per 100,000 resident population in 1987 were about 1.87, 19.7, and 26.5, respectively. An attempt is made to use international death rates to compare Jeddah with other countries. The figures reveal higher death rates per vehicle travel and per resident population but lower rate per registered vehicle than in some industrialized countries. An additional attempt was made to estimate the cost of road traffic fatalities in Jeddah, which is an extremely difficult task due to lack of reliable data. This study shows that the cost of 1987 road fatalities in Jeddah is estimated to be 648.7 million Saudi Riyals (US$172.5 million).

Polish pilgrim-tourists

Pilgrimage traditions probably predate Christianity in Poland (966 A.D.), and have been shaped by prevailing political, social, and economic conditions, as well as religious belief. International shrines, such as Czestochowa, now attract four to five million visitors per year and are unique even to Christianity; visits to them are primarily undertaken on foot by parish youths and may involve hundreds of kilometers of travel. Because of World War II damage and subsequent Soviet repression, virtually no tourist infrastructure exists. Local residents are, thus, deprived the opportunity of economically benefiting from the pilgrimage tourist phenomenon.

A Microcomputer-based Forecasting Model: Potential Applications for Emergency Response Plans and Air Quality Studies

Most atmospheric transport and diffusion models within emergency response systems have very limited physics and are forced to rely on the assumption that wind and turbulence conditions at the time of the release will be representative over the period for which dispersion must be predicted. For releases where the principal concern is about the first few kilometers of travel, such an assumption is appropriate. However, for large accidental releases during stable conditions, the plume may travel for several hours before it is diluted to safe levels and the assumption of persistence may be inappropriate, particularly for transport in complex terrain. Under these circumstances, a model that can forecast changes in wind and turbulence conditions is required. We have installed such a model on microcomputers and tested it in complex terrain near Salt Lake City. One-hour tracer releases produced surface concentrations that remain high for much longer times than that expected based on one hour’ travel time with the...

Grazing behavior of rangeland beef cows differing in milk production

Differences in grazing behavior among Hereford (HH), 50% Angus-50% Hereford (AH), 50% Simmental-50% Hereford (1S1H) and 75% Simmental-25% Hereford (3S1H) lactating cows grazing foothill range were measured using vibracorders and pedometers to estimate daily grazing hours and distance traveled, respectively. There were four 10-day grazing periods during July and August. Cow weight, calf weight and milk production estimates were taken prior to Periods 1 and 4. During Periods 1, 2 and 4, the 48 cows were located on a daily basis between 06.00 and 09.00 h, and each animal location was recorded on gridded aerial photo maps. Pasture use was defined as the amount of total area utilized for grazing for the four periods. The overall mean for daily grazing hours was 9.4 h day −1 (633 observations) and no significant breed type differences were found. Daily grazing hours increased from 8.0 to 10.0 h day −1 during the 40-day observation period. Milk production and calf age significantly influenced daily grazing hours and the partial regression coefficients were 0.05 h·day −1·kg·day −1 and −0.02 h·day −1·day −1, respectively. The overall mean distance traveled was 4.7 km day −1 (82 observations) and followed the same trend as daily grazing hours. For each kilometer of travel, 2h were spent grazing during the four grazing periods. The 1S1H cows traveled less ( P < 0.05) than HH, AH and 3S1H cows. Breed type means were 5.0, 4.8, 4.1 and 4.8 km day −1 for HH, AH, 1S1H and 3S1H cows, respectively. The overall mean for pasture use was 103 ha per cow (47 observations) and breed type was not significant in explaining variation in pasture use. For each kilogram increase in calf weight (adjusted for cow condition), pasture use increased by 0.5 ha ( P < 0.05). Thus, the grazing behavior of different breed types under rangeland conditions was similar.