A comparison of three methods for assessing the walkability of the pedestrian environment

This paper presents the results of a research project conducted in the UK designed to increase understanding of the factors which influence levels of walking and pedestrian route choice. It describes a number of techniques that were used to assess the pedestrian environment from a pedestrian’s perspective. These techniques included a computer based tool developed using stated preference surveys to determine the relative values of a range of factors in the pedestrian environment; an on-street survey that was designed to investigate values and attitudes towards different attributes of the pedestrian environment along a route; and finally an ‘on the move survey’ where pedestrian volunteers were interviewed while walking along the route in order to get an actual account of their experiences as they walk. A case study is then used to show the benefits and disadvantages of using these different techniques and compares results for a pedestrian route in the City of Leeds in the UK. The results indicate that there were a number of pedestrian attributes considered important by pedestrians when walking including pavement cleanliness, safe crossing places, good connectivity and sense of security. The three approaches complement one another and have highlighted in different ways that the walking experience is affected by the cumulative impact of multiple interactions (both positive and negative) as people walk in the pedestrian environment.     

Traffic barriers and pedestrian crossing behaviour

This paper is concerned with the relationships between traffic conditions and pedestrian behaviour which determine the extent of barrier effects. These relationships are examined on a high-density mixed-use street in central Edinburgh. Such streets are generally important routes for both pedestrians and vehicles, where there is maximum potential for conflicts between them. Crossing strategies and pedestrian trip-making activity are shown to be modified in response to changes in traffic conditions, notably to changes in traffic volumes and parking activity. Barrier effects are seen to vary markedly with the age group of pedestrians. The findings are related to pedestrian safety on such streets and to issues involved in the design and implementation of traffic management schemes. It is concluded that barrier effects on pedestrians should be a standard consideration in scheme design and implementation.     

Recreational traffic management: The relations between research and implementation

Traffic management in National Parks is necessary in order to avoid the negative effects of car traffic. Implementing traffic management measures can be difficult, due to public resistance or other problems. A research project in the Veluwezoom National Park in The Netherlands shows that there are two important reasons for problematic implementation. The first reason is a lack of knowledge about the recreational use of the area. The second reason is the interdependence of actors involved. Both aspects need to be considered and related to each other in order to make more realistic traffic management plans.     

Estimating pedestrian and cyclist activity at the neighborhood scale

In most parts of the U.S., data on bicycle and pedestrian activity at the neighborhood scale are sparse or non-existent, despite the importance of such data for local planning. Here, a simple small-area estimation method is used to pair travel survey with land use and census data to estimate cyclist and pedestrian activity for census tracts in the state of California. This method is an improvement on fixed per-capita estimates of activity based only on regional or statewide averages. These activity estimates are then used to calculate the intensity of road use by cyclists and pedestrians, and crash rates for these road users. For California, the intensity of pedestrian and cyclist road use in urban census tracts is double that found in suburban tracts, while use in suburban tracts is an order of magnitude greater than that found in rural tracts. Per-capita estimates would suggest substantially smaller differences between neighborhood types. On the safety side, although non-severe crashes involving cyclists and pedestrians are much more likely in more urban areas, severe crash rates for the non-motorized modes exhibit no clear spatial pattern. The method used is simple and easily replicable, potentially filling a critical need for bicycle and pedestrian planners.     

Assessment of non-recurrent congestion caused by precipitation using archived weather and traffic flow data

Since precipitation has a negative impact on traffic congestion, there have been various studies for modeling the relationship between precipitation and its impact on traffic flow. However, due to limitations on existing data, none of the previous studies have accounted for the estimation of the total delay caused by precipitation. The objective of this study is to estimate the non-recurrent traffic congestion on freeways caused by precipitation. To accomplish this objective, archived weather and traffic data for the year 2008 from the Korean Freeway Systems was collected and analyzed. As a result, non-recurrent traffic congestion was about 1.6 million vehicle-hours due to rainfall and 186,000 vehicle-hours due to snowfall in 2008. In addition, simple analyses were performed to describe the average non-recurrent traffic congestion per unit distance as a function of precipitation and a function of the time period of precipitation. Although precipitation events might not be handled by human efforts, these results will assist in making strategic plans such as active speed management and contingency planning for mitigating traffic congestion due to precipitation.     

Increasing the resilience of air traffic networks using a network graph theory approach

Air traffic networks are essential to today’s global society. They are the fastest means of transporting physical goods and people and are a major contributor to the globalisation of the world’s economy. This increasing reliance requires these networks to have high resilience; however, previous events show that they can be susceptible to natural hazards. We assess two strategies to improve the resilience of air traffic networks and show an adaptive reconfiguration strategy is superior to a permanent re-routing solution. We find that, if traffic networks have fixed air routes, the geographical location of airports leaves them vulnerable to spatial hazard.     

A review of deterministic, stochastic and hybrid vehicular exhaust emission models

Vehicles spend more time near junctions and intersections in different driving modes, i.e., queuing, decelerating or accelerating and thus generating more pollutants than at road links [Claggett, M., Shrock, J., Noll, K.E., 1981. Carbon monoxide near an urban intersection. Atmos. Environ. 15, 1633-1642]. As a result, the receptors in these urban corridors are prone to frequent exposures of high pollutant concentrations (episodic conditions). In order to predict such ‘episodes’, an air quality model, capable of estimating the entire range (middle and extremes) of pollutant concentration distribution is needed. Hybrid models (combining deterministic and statistical distribution models) have demonstrated the ability to predict the entire range of pollutant concentrations in such co mplex dispersion situations with reasonable accuracy [Jakeman, A., Simpson, R.W., Taylor, J.A., 1988. Modelling distributions of air pollutant concentrations-III: Hybrid modelling deterministic-statistical distributions. Atmos. Environ. 22 (1) 163-174]. The present paper reviews the relevant deterministic and stochastic based vehicular exhaust emission models that may be hybridized and thus generate a hybrid model with improved prediction accuracy. The paper also describes the implications of hybrid models in formulating the Episodic-Urban Air Quality Management Plan (e-UAQMP).     

Transit-oriented development,integration of land use and transport,and pedestrian accessibility: Combining node-place model with pedestrian shed ratio to evaluate and classify station areas in Lisbon

Transit-oriented development is being actively promoted as an urban design model for areas around transit stations. In addition, planning for accessibility is being promoted, which requires integrating land use with transportation planning, and to match the transportation features with the intensity and diversity of land use of the station areas. Nevertheless, and despite the evident similarities between the two approaches, an integrated evaluation tool of a station area in terms of its transportation, land use, and urban design features is missing. In this paper, we bring into the literature on integration of land use and transport a key feature of the transit-oriented development literature: the urban design features of the station areas, in particular their pedestrian friendliness. By complementing the node-place model with an evaluation of the pedestrian connectivity of station areas of Lisbon, we combine these two perspectives in order to evaluate and classify station areas in three different aspects: land use, transportation, and walkability conditions. Our results show that a balanced node-place is not necessarily a transit-oriented development, and vice versa, and so a complementary analysis of both is useful to identify and classify a station area. Therefore, we suggest a typology of station areas based on the three components, which might be used as a planning tool for the development of the station areas into balanced transit-oriented development areas.     

科技支撑——李居昌：创新的舞台

中国公路学会是全国公路科技工作者共同的家园,它搭建的交流大舞台,为推进我国公路交通科技进步、促进公路交通事业发展发挥了重要作用。     

Modelling dependence between tourism demand and exchange rate using the copula-based GARCH model

This paper investigates dependence between tourism demand and exchange rate, using the case of China, and from a new perspective by using copula–GARCH models. The empirical results show that the volatility of exchange rate is not a determinant factor in fluctuation of China's inbound tourism demand from the countries being studied. Furthermore, only Russia exhibits risk-adverse behaviour with extreme SUR depreciation, or CNY appreciation associated with an extreme decline in arrivals. Third, introducing the tail dependence and dynamic dependence between growth rates of tourism demand and exchange rate add much to the explanatory ability of the model. The findings of this study have important implications for destination manager and travel agent as it helps to understand the impact of exchange rates on China inbound tourism demand and provide a complementary academic approach on evaluating the role of exchange rates in the international tourism demand model.     

Airport traffic and financial performance: a UK and Ireland case study

The aim of this paper is to examine the development of air services at UK and Irish airports since 1998 and to assess the impact on airport financial performance. A sample of 14 medium/small sized UK airports and three Irish airports is used. The traffic analysis shows that low cost carriers have been largely responsible for strong passenger growth and increased passenger load at a number of regional airports. Some of these carriers use established primary and regional airports whilst others seek out small secondary airports. The airports with a high proportion of low cost traffic tend to have lower unit revenues, particularly as regards airport charges, demonstrating their desire to remain price competitive to capture this type of traffic.     

Competitive multi-facility location games with non-identical firms and convex traffic congestion costs

This paper studies a set of heterogenous competitive firms simultaneously locating facilities at a set of locations to serve a set of markets. Firms incur firm-specific transportation, congestion, and location costs, and market price is linear and decreasing in the amount shipped to the market by all firms. First, firms’ market-supply decisions for given facility locations are characterized using a variational inequality formulation. Then, firms’ location decisions are analyzed. A heuristic method is provided for finding equilibrium locations, and its computational efficiency is compared to a random search method.     

The hierarchy of roads, the locality of traffic, and governance

This study investigates the use of road networks both within and outside of home jurisdictions (city (or town) and county of residence) by analyzing GPS data collected in the Minneapolis—Saint Paul metropolitan area. The study tracked volunteers' travel behavior to determine which roads (and thus which class of roads) users chose to accommodate their travel needs. More than half of the travel on county roads and city streets occur outside of one's home city, but most travel is within one's home county. The average share of travel distance in the home county is more than 70% for both county and city streets. The high share, which does not account for non-residents destined for the county to work or shop, e.g., implies that the free rider problem on city and county streets at the county level is minimal. Of particular concern is travel on city roads in cities other than one's own. To the extent that this is to go to a destination in that city, that travel is also local. However, because city and county roads are typically funded by those jurisdictions from land-based sources such as property taxes, through trips with neither end in the city through which they are traveling are in a very real sense “free riders”, and pose a problem. With growing trip lengths and emerging economies of scale in road management, it may be appropriate to consider moving more roads from township, town, or city level to the county level of government.     

The multi-class, multi-criterion traffic equilibrium and the efficiency of congestion pricing

We consider the effect of the so-called second-best tolls on the price of anarchy of the traffic equilibrium problem where there are multiple classes of users with a discrete set of values of time. We derive several bounds of the price of anarchy for this problem when the tolls are considered and not considered as part of the system cost, with the time-based criterion and the cost-based criterion, respectively. All the bounds give us useful information on the effect of the tolls, which can be used to design network toll schemes.     

Decomposing the decoupling of Danish road freight traffic growth and economic growth

In recent years many European countries have seen a decoupling of the growth in road freight traffic (vehicle kilometres) from economic growth. A similar decoupling has not been observed in road freight transport (tonne kilometres). In this paper the historical growth in national Danish road freight traffic and transport is attributed to causes using a Divisia index decomposition method. It is demonstrated that overall road freight traffic growth is a consequence of often opposite pointing growth effects in the underlying factors. The observed decoupling of road freight traffic growth from economic growth is mainly the result of use of larger vehicles, increasing average loads, and less empty running. Growth in road freight transport is primarily caused by growth in production. A decrease in the number of tons lifted per tonne produced (the handling factor) is offset by an increase in the tonne kilometres per tonne lifted.     

铁路交通枢纽与城市综合体设计初探

通过对国内铁路旅客车站交通枢纽设计模式及国外交通枢纽城市综合体典型案例的分析和总结．提出铁路旅客车站结合物业开发设计并形成交通枢纽城市综合体将是国内铁路旅客车站发展趋势之一的观点,以期对今后铁路旅客车站的建筑设计有所启示。     

Hierarchical system of road networks with inward, outward, and through traffic

This paper formulates a continuous model of a grid road network for determining the optimal hierarchical system of road networks. The hierarchical system is represented as the proportions of area taken up by roads at each level of the hierarchy. The objective is to derive the optimal ratio of road areas that minimizes the total travel time. The model explicitly incorporates inward, outward, and through traffic as well as inner traffic to examine how traffic composition affects the optimal ratio of road areas. The result reveals that the optimal ratio of major arterial roads increases with inward, outward and through traffic.     

快速交通建设与居住选址决策的研究

从城市出行的目的、时间、流量及其空间的分布、方式等几方面阐述了快速交通系统是现代化城市交通布局不可缺少的一部分。并从理论上 ,应用时空替代效应分析了快速交通建设与居住选址决策之间的辨证关系     

Impacts of LCC growth on domestic traffic and fares at largest US airports

This paper examines the evolution of domestic origin-destination air traffic and fares at the top 200 airports in the US between 1990 and 2008, with a focus on the impacts of low-cost carrier entry and growth. By 2008, 95 of the airports had an aggregate low-cost carrier market share of domestic traffic greater than 20%, up from 27 airports in 1990. Their entry or substantial growth at US airports has had significant impacts on lowering average fares and stimulating passenger volumes. This market stimulation effect has, however, diminished in recent years, as the difference in average fares between carrier types has narrowed and as the number of additional US domestic origin-destination markets able to support their entry has dwindled.     

The effects of area-wide road speed and curvature on traffic casualties in England

Transport provides a range of benefits to society in terms of mobility, access and economic growth. There are however negative impacts of transport, not least in terms of environmental degradation, damage to property, traffic accidents and loss of life. This paper focuses on road traffic accidents, the reduction of which is an important aim of transport policy world wide. The primary objective of this paper is to develop a series of relationships using spatially disaggregated area-level cross-sectional data between different traffic casualties, road traffic speed and road curvature by controlling for other contributing factors associated with area characteristics. The spatial units of the analysis are the 8019 census wards in England. Ward-level casualty data are disaggregated by severity of the casualty (such as fatalities, serious injuries and slight injuries) and by the severity of the casualty related to various road users.The results suggest that increased average speed within a ward is positively associated with total fatalities and serious injuries; and road curvature is found to be negatively associated with road accidents.