Announcement of Pre-Licentiate Final Seminar, "Congestion Effects in Transport Modelling and Forecasting "

Title: "Congestion Effects in Transport Modelling and Forecasting "
Time: Thursday, 19th of March, 2015, 10.00 – 12.00
Location: Nash-Wardrop Seminar Room, Ground Floor, Teknikringen 10A, KTH

Respondent: Jens West, PhD Student at KTH
Opponent: Per Olov Lindberg, Researcher at KTH
Supervisors: Maria Börjesson, Jonas Eliasson, KTH, and Oded Cats Assistant Professor in Public Transport, TU Delft

Abstracts

Paper 1: Ex-post evaluation of national transport model – Gothenburg congestion charges application

This paper evaluates the forecast effects of the Gothenburg congestion charges implemented in 2013. We find that the predicted traffic reductions and travel time gains were close to the observed in the peak. However, the traffic reduction was over-predicted in off-peak, because the model does not capture all of the various adaptation strategies applied to discretionary trips. The predicted route choice is highly sensitive to the VTT and distance cost implemented in the assignment model. To improve the route choice a continuous VTT distribution estimated from SP data was implemented but had to shifted upwards, adding to the evidence that VTT inferred from SP data might not reveal travellers long-term preferences.

Paper 2: Integration of dynamic traffic assignment with a travel demand model for the Stockholm region

The need to more precisely represent the consequences of congestion mitigation policies in urban transport systems calls for replacement of the static equilibrium assignment by DTA in the integrated travel demand and traffic assignment models. Despite of the availability of DTA models and despite of the conceptual clarity of how such integration should take place, only few operational model systems have been developed for large-scale applications. We report on replacement of the static traffic assignment by two different DTAs in the four stage demand model for the Greater Stockholm region: the macroscopic analytic Visum DUE and the microscopic simulation TransModeler. First results show that even without systematic calibration the DTA is in reasonable agreement with observed traffic counts and travel times. The presented experiments did not reveal a striking difference between using a macroscopic and a microscopic assignment package. However, given the clear trend to microscopic modelling and simulation on the travel demand side, the use of a micro-simulation-based DTA package appears more natural from a system integration perspective.

Paper 3: Appraisal of increased public transport capacity

One of the most common motivations for public transport investments is increased capacity. However, appraisal methodologies for projects meant to increase capacity are relatively less well developed compared to methodologies for projects aiming to reduce travel times. Each of the consequences of capacity limitations - crowding, risk for denied boarding and unreliable waiting and travel times - can increase the generalized travel costs. The appraisal of capacity improvements requires supply and demand models able to capture the processes that lead to uneven distributions of vehicles and passengers and monetary valuations of e.g. crowding, delays and unexpected waiting times. This paper integrates these building blocks into a comprehensive framework for appraisal. A case study of a metro extension that partially replaces an overloaded bus network in Stockholm demonstrated that congestion effects may account for a substantial share of the expected benefits. A cost-benefit analysis based on a conventional static model will miss more than half of the benefits. This suggests that failure to represent dynamic congestion effects may substantially underestimate the benefits of projects primarily designed to increase capacity rather than reduce travel times.

Paper 4: Evaluating transit preferential measures - priority lanes, boarding and control strategies

Assessment of bus service improvements such as bus lanes, allowed boarding through all doors and headway-based holding control ideally requires a simulation model that combines features of both classical analytical models and microscopic simulation. However, as the usage of such models has been limited, their validity has hitherto remained low. BusMezzo, a dynamic transit operations and assignment model, was developed to enable the analysis and evaluation of transit performance and level of service under various system conditions. This paper describes two case studies were assessment of bus service improvements in BusMezzo was tested and validated. The model was shown to predict travel time improvements well, while overestimating some of the headway variability effects. It turned out that the tested measures had a positive system impact and that there were synergy effects.

Welcome,

Maria

Maria Börjesson

Associate Professor Transport Systems Analysis

Director Centre for Transport Studies, Royal Institute of Technology

maria.borjesson@abe.kth.se; +46-70-258 32 66

mail: Teknikringen 10, 100 44 Stockholm, Sweden