Fraunhofer Institute for Industrial Mathematics ITWMAt Fraunhofer ITWM, we are working with our partners to develop »LinTim«, an open-source software solution for the comprehensive planning and optimization of public transportation. It enables users to carry out, analyze, and evaluate all key planning steps – from route network design to delay management – within a single integrated environment.
LinTim Header
With »LinTim«, we analyze public transportation as an integrated system. The open-source software brings together all key steps of transportation planning in a single environment.
© Fraunhofer ITWM
One-Stop Transportation Planning: From Routes to Schedules
»LinTim – Line Planning and Timetabling«: Holistic Planning and Optimization of Public Transportation
»LinTim« is a scientific software library for the mathematical planning and optimization of public transportation systems. The project was launched in 2007 at the University of Göttingen by our current institute director, Prof. Dr. Anita Schöbel, and is now being further developed jointly by Aalto University, RPTU Kaiserslautern-Landau, and a team here at Fraunhofer ITWM. Findings from various research projects and theses are continually incorporated into the package’s further development, and »LinTim« has been available as open-source software since 2018.
All Steps in Public Transportation Planning in a Single Software Application
The planning of a bus, train, or streetcar network takes place in several sequential steps. Typically, these steps are considered individually. With »LinTim«, however, we integrate all planning steps into a single environment and make their interactions visible.
A typical planning process begins, for example, with the question of where to strategically place stops. Next, it is determined which routes will operate, which paths they will take, and how frequently they will run. Building on this, a schedule is created with specific departure and arrival times. This is followed by route planning, which determines which vehicle will operate which route and how vehicles will switch between different routes. Another key focus is delay management. This involves, for example, determining whether a connecting vehicle should wait for delayed passengers or not. In addition, »LinTim« also supports fare planning – that is, the development of fair and transparent fares.
Highlighting Interactions Between Planning Steps
Decisions made in early planning phases often influence later steps. For example, a route that seems reasonable at first glance can make it difficult to create a robust schedule. Conversely, a good schedule can simplify route planning or reduce delays. »LinTim« makes these relationships visible.
Users can try out different planning approaches and immediately examine their effects on the overall system. This allows them to find solutions that often remain hidden in the traditional, strictly compartmentalized planning process. For example, transit networks can be designed early on in such a way that later schedules become more stable and resilient to disruptions.
Flexible Optimization Models for Transportation Companies and Research
For each planning step, »LinTim« provides various mathematical models and optimization methods. This means users can select different algorithms and compare their results. As a result, the software is suitable for both scientific research and for developing and evaluating new planning methods.
In addition, »LinTim« supports the analysis and visualization of results as well as the use of realistic and artificially generated datasets. This allows new methods to be tested and compared under reproducible conditions.
Multimodal Transportation Planning for Connected Mobility
Modern mobility has long since ceased to consist of just one mode of transportation. That is why »LinTim« also supports multimodal transportation planning. In doing so, we consider multiple modes of transportation simultaneously, such as buses, trams, trains, bicycles, walking routes, and ride-sharing services. This enables a realistic analysis of mobility chains and transfer processes.
Furthermore, we can examine how passenger demand is distributed across different modes of transportation, how shared infrastructure can be used efficiently, and how new mobility services can be integrated into existing transportation networks. In this way, »LinTim« opens up new possibilities for planning sustainable and interconnected mobility systems.
Public Transportation Planning with Helsinki as an Example
Sustainable Mobility and Energy-Efficient Transportation Planning
This is because public transportation is a crucial component of sustainable mobility. Well-planned transportation systems help reduce emissions and noise pollution while creating attractive mobility alternatives. While transportation planning has traditionally focused primarily on passenger comfort and operating costs, another aspect is becoming increasingly important: energy consumption.
With »LinTim«, we can evaluate different planning scenarios not only in terms of costs, travel times, or connection reliability, but also analyze their impact on energy demand. This enables the development of transit networks that are both economical and sustainable.
From Traffic Planning to Energy Simulation
A particular advantage arises from the integration of »LinTim« into the »VMC® – Virtual Measurement Campaign« software family developed at Fraunhofer ITWM. There, the solution is available as the VMC® LinTim module. The underlying georeferenced environmental database contains, among other things, information on road networks, topography, road quality, and traffic data.
By linking this data with the optimization methods in »LinTim«, we can, for example, calculate the energy requirements of planned bus routes and directly incorporate energy efficiency as an additional optimization criterion. This allows for the comparison of different route network and schedule concepts and their evaluation in terms of cost, travel time, robustness, and energy consumption.
In this way, VMC® LinTim supports transportation planners in making informed decisions and identifying the best solutions for complex public transportation challenges.
Open Platform for Research and Development
The modular architecture of »LinTim« facilitates the integration of new algorithms and planning approaches. Researchers can integrate their own methods and compare results directly with existing methods. Interfaces based on simple data formats enable the use of various programming languages. Core functions are available for Python and Java, among others.
Thanks to this open approach, »LinTim« has evolved into a platform that bridges the gap between mathematical research and practical issues in transportation planning.
Our Project Partners:
»LinTim« is being developed jointly by several institutions and is continuously being expanded. This collaboration brings together mathematical research, transportation planning, and software development across national borders.
Currently, »LinTim« is maintained and further developed at the following locations:
- Aalto University, Espoo (Finland)
- University of Kaiserslautern-Landau
- Fraunhofer ITWM, Kaiserslautern
The project is led by Asst. Prof. Dr. Philine Schiewe of Aalto University.