Simulation Studies for Improved Efficiency in Road and Rail Freight Transports
Time: Thu 2021-06-10 14.00
Subject area: Transport Science, Transport Systems
Doctoral student: Ingrid Johansson , Transportplanering, Järnvägsgruppen, JVG
Opponent: PhD C. Tyler Dick, University of Illinois at Urbana-Champaign (UIUC), Railway Transportation and Engineering Center (RailTEC)
Supervisor: Guest professor Markus Bohlin, Transportplanering, Järnvägsgruppen, JVG; Associate professor Oskar Fröidh, Järnvägsgruppen, JVG, Infrastruktur, Transportplanering; Dr. Behzad Kordnejad, Transportplanering, Järnvägsgruppen, JVG; Dr Carl-William Palmqvist, Lund University, Department of Technology and Society
Abstract
The demand for road and rail freight transport continues to grow with the expanding economy, while the climate crisis requires reduction in greenhouse gas emissions. Therefore, tools and solutions for reducing fossil fuel use and enabling more efficient use of infrastructure are needed. This thesis utilises microscopic and macroscopic traffic simulation as tools to improve certain aspects of road and rail transport planning in the operational, tactical, and strategic planning time horizons.
For road freight transports conducted with heavy-duty vehicles, fuel consumption can be reduced by smarter driving. Strategic planning concerning introduction of intelligent and connected vehicles is needed, along with planning of actual vehicle operations. Microscopic road traffic simulation is utilised to show that heavy-duty vehicle platooning, which lowers the fuel consumption through reduced aerodynamic drag, can be conducted on two-lane highway stretches without disturbing surrounding traffic. Further, substantial reduction of the fuel consumption can be achieved by applying fuel-optimal deceleration trajectories, assuming available information about the traffic situation ahead.
Shifting freight transports from roads to railways is another possible measure to reduce emissions. Previous simulation studies of railway traffic has mainly focused on passenger trains, combined with not including freight train departures before the scheduled timetable, even though it commonly occurs in Sweden. Therefore, both microscopic and macroscopic railway traffic simulation, with and without allowing early freight train departures, is conducted in a case study. The resulting freight train punctuality is closer to empirical punctuality when early departures are included.
A modal shift from road to rail transport increases capacity utilisation of railway networks, and is only possible within available capacity. Therefore, reliable methods for capacity analysis are needed. A method for capacity analysis is introduced and evaluated, with particular focus on railway station analysis. An advantage of this method is it can be used in tactical and strategic planning of future timetables and infrastructure.