Aggregating mobile object trajectories: cumulative time geographic density estimation for GPS data

We present new approaches that expand upon the time geographic density estimation (TGDE) framework previously employed to estimate potential path trees. In the past, TGDE metrics have identified possible locations an individual moving object may have passed between, given known origin and destination points. This paper utilizes a new form of TGDE to investigate taxicab GPS traces over a specified time horizon with position ‘gaps’. To this end, we propose a new extension to the TGDE framework, TGDE-C, which is used to determine the cumulative TGDE values for a group of GPS traces, at a given location. These metrics are applied to multiple taxis and allow for time of day analysis. Additionally, we combine these new extensions with existing TGDE metrics that allow us to determine how accessible individual or groups of vehicles are to urban opportunities.     

基于出租车GPS数据的路段平均速度估计模型

为了解决现有基于GPS数据的路段平均速度估计模型应用条件苛刻、难以满足低成本和高精度信息需求问题,考虑不同类型GPS车辆运行特征,设计了两个基于出租车GPS数据估计路段平均速度的改进模型.基于两个改进模型,设计了路段平均速度的融合估计方法.用某城市局部路网的出租车GPS数据验证两个改进模型,并与传统模型进行了对比分析....     

Incorporating e-Technology to Advantage in a Greener Taxi Industry and its Impact on Driving Performance and Safety

Abstract

New technologies, especially advances in telecommunications, have had profound impacts on everyday life and brought even greater changes to some business models. Taxis represent one of the major modes of transportation in urban areas but they face a number of problems, including their environmental impacts. The status of the taxi industry in Taiwan is revealed and analyzed in this study. A new business model for the extensive and popular use of smart phones is proposed. However, it is important to know whether their use is both effective and safe. Two field experiments were executed to examine the effects on taxi drivers of using a navigation system installed in a GPS PDA phone. The results revealed that the efficiency of drivers using such a portable navigation system was better than those relying on paper maps in unfamiliar urban areas. Furthermore, performance in terms of safety was also better than those who used an on-board navigation system. In summary, incorporating e-technology can promote a taxi company's competitiveness and a driver's performance and safety as well as offer environmental benefits.     

出租车跨区经营方案研究——以成都中心城区、郫县为例

为了促进城乡交通一体化发展,对城郊出租车跨区经营进行了研究。作者从郊区(县)融入中心城区,城乡交通一体化,郊区(县)客运结构合理化,郊区(县)客运市场规范化四个方面分析了实行出租车跨区经营的必然性和意义。在对我国出租车跨区经营的实践进行总结的基础上,分析了实行出租车跨区经营需解决的问题,并提出了实行出租车跨区经营分三个阶段的具体方案。     

Overview of public transport policy developments in South Africa

In South Africa, a restructuring of the public transport system is currently under way. In the bus industry the tender for contract system is being implemented, the commuter rail sector is being recapitalised and the minibus taxi industry recapitalization programme is in its early stages. Progress with policy implementation across the modes of transport, modal split trends and issues that hamper the full development of the public transport industry are discussed in this paper. Medium to long term policy and strategy initiatives that will further inform the development of the industry are also highlighted in this chapter.     

Non‐physical barriers to traffic flow and the PTA programme of action: problems and prospects

A lot of resources have .been committed to the provision of transport infrastructure in Eastern and Southern Africa. Some of these resources have been borrowed from outside and have to be repaid. Hence the need to maximize their use. However, this is being minimized by non‐infrastructural bottlenecks to traffic flow. These range from macro‐economic constraints with implications for passenger (bus) transport such as the non‐availability or acute shortage of foreign exchange to slow, cumbersome documentation procedures particularly for cross‐border traffic.

The Preferential Trade Area (PTA) for Eastern and Southern Africa is geared to the reduction and eventual elimination of actual and potential non‐physical barriers to traffic flow, for which it has instituted a number of schemes. After introductory remarks on the sub‐regional economy, its transport sector and avenues for sub‐regional cooperation and the implementation of these schemes is assessed and other non‐physical barriers yet to be addressed by the PTA are examined before conclusions are drawn.     

Customers’ selections between premium electric taxis and liquefied petroleum gas taxis

Reducing roadside emissions is a common challenge in metropolitan cities. In Hong Kong, conventional liquefied petroleum gas taxis are one of the main contributors to roadside emissions as they operate on the streets 24 h a day with a long daily driving mileage. Moreover, these taxis suffer from a severely poor service reputation. To enhance the environmental friendliness and service quality of the taxi industry, this study explores the market potential of operating premium electric taxis in the dispatching mode. A stated preference survey was conducted to 1410 taxi customers about their taxi-riding choices between premium electric taxis and conventional liquefied petroleum gas taxis. In total, 5640 observations were obtained and used to develop a series of binary logistic regression models with different model formulations for the determination of the significant factors influencing customers’ selections. The findings indicate that walk time to and wait time for taxis were the most critical concerns to the customers, and they were more willing to take premium taxis if their journey distance was longer and their desired improvement on taxi service quality was greater. The socio-demographic status of taxi customers also influences their choices. The associated policy implications are discussed for promoting taxis with better service quality and fewer roadside emissions. The findings provide some policy insights to other international cities that have a similar taxi market to Hong Kong.     

The lurch towards formalisation: Lessons from the implementation of BRT in Johannesburg,South Africa

The City of Johannesburg, South Africa, implemented the first phase of its Bus Rapid Transit (BRT) system named Rea Vaya between 2009 and 2011. The system design and organisational arrangements drew heavily on precedents from South America, especially insofar as BRT is used as an instrument for securing the transformation and formalisation of a fragmented and problematic informal public transport industry. Despite the inevitable transition problems, the formalisation scheme appears to be generally successful – an outcome that surprised many analysts as it follows a long history of mistrust, resistance, and unsuccessful interventions between government and the minibus taxi industry. The paper offers an analysis of the reasons for the successful transformation of participating taxi operators, by using a life-cycle analogy. We argue that the minibus-taxi industry in South Africa has reached a state of stasis and maturity, with limited opportunities for further growth in its present form. BRT, as it is implemented locally, offers opportunities for re-invention – for moving onto new a potential growth trajectory – by overcoming the binding constraints of informality and by opening up new markets to operators. The life-cycle analysis also offers some insights into critical success factors that, if not met in the long run, could jeopardise the longevity and scalability of the formalisation project. The paper concludes with insights regarding the planning and management of BRT systems to maximise their potential for leveraging the formalisation of informal operators, both in South Africa and in other developing countries.     

Analysis of taxi demand and supply in New York City: implications of recent taxi regulations

This paper investigates temporal and weather-related variation in taxi trips in New York City. A taxi trip data-set with 147 million records covering 10 months of activity is used. It is shown that there are substantial variations in ridership, taxi supply, trip distance, and pickup frequency for different time periods and weather conditions. These variations, in turn, cause variations in driver revenues which is one of the main measures of taxi supply–demand equilibrium. The findings are then used to discuss the anticipated impacts of two recently enacted taxi regulation changes: the first fare increase since 2006 and the E-Hail pilot program which allows taxi hailing with smart phone applications. The fare increase is estimated to cause varying levels of revenue increase for different time periods. E-Hail apps are not expected to offer considerable improvements at all times, but rather when both adequate taxi supply and demand occur simultaneously.