A new approach to evaluating on-road public transport priority projects: balancing the demand for limited road-space

Despite widespread growth in on-road public transport priority schemes, road management authorities have few tools to evaluate the impacts of these schemes on all road users. This paper describes a methodology developed in Melbourne, Australia to assist the road management authority, VicRoads, evaluate trade-offs in the use of its limited road-space for new bus and tram priority projects. The approach employs traffic micro-simulation modelling to assess road-space re-allocation impacts, travel behaviour modelling to assess changes in travel patterns and a social cost benefit framework to evaluate impacts. The evaluation considers a comprehensive range of impacts including the environmental benefits of improved public transport services. Impacts on public transport reliability improvements are also considered. Although improved bus and tram reliability is a major rationale for traffic priority its use in previous evaluations is rare. The paper critiques previous approaches, describes the proposed method and explores some of the results found in its application. A major finding is that despite a more comprehensive approach to measuring the benefits of bus and tram priority, road-space reallocation is difficult to economically justify in road networks where public transport usage is low and car usage high. Strategies involving the balanced deployment of bus and tram priority measures where the allocation of time and space to PT minimises negative traffic impacts is shown to improve the overall management of road-space. A discussion of the approach is also provided including suggestions for further methodology development. Copyright Springer Science+Business Media, LLC 2007Bus priority, Economic evaluation, Road space management, Traffic simulation, Traffic planning, Tram priority,

Flexible Substitution Patterns in Models of Mode and Time of Day Choice: New evidence from the UK and the Netherlands

Modelling the temporal response of travellers to transport policy interventions has rapidly emerged as a major issue in many practical transport planning studies and is recognised to hold particular challenges. The importance of congestion and its variation over the day, together with the emergence of time-dependent road user charging as a policy tool, emphasise the need to understand whether and how travellers will change the timing of their journeys. For practical planning studies, analysts face a major issue of relating temporal changes to other behavioural changes that are likely to result from policy or exogenous changes. In particular, the relative sensitivity of time and mode switching has been difficult to resolve. This paper describes a study undertaken to determine the relative sensitivity of mode and time of day choice to changes in travel times and costs and to investigate whether evidence exists of varying magnitudes of unobservable influences in time of day switching. The study draws on data from three related stated preference studies undertaken over the past decade in the United Kingdom and the Netherlands and uses error components logit models to investigate the patterns of substitution between mode and time of day alternatives. It is concluded that the magnitude of unobserved influences on time switching depends significantly on the magnitudes of the time switches considered. With time periods of the magnitude generally represented in practical modelling, i.e. peak periods of 2-3 hours, time switching is generally more sensitive in this data than mode switching. However, the context of the modelling and the extent to which relevant variables can be measured will strongly influence these results

Equilibrium Trip Scheduling in Congested Traffic under Uncertainty

Whilst traditional modeling and research efforts put emphasis on the effect of congestion on travel choices, recently more and more studies examine the notion of travel time uncertainty on travel decision. In particular, travel time reliability forms an important component in modeling route choice and trip scheduling. This paper considers equilibrium trip scheduling under random travel delay in a single bottleneck. Travelers form a heterogeneous population with distinctive requirements on the probability of punctual arrival and each with a different valuation toward earliness and lateness. The analysis shows that random delay plays a significant role in travel costs and introduces substantial differences in the queuing pattern, departure and arrival times, as compared with the traditional deterministic model