Multi-Modal Public Transit Route Planner (Belgium)

A high-performance Java route planning engine for multi-modal public transportation across Belgium. The system integrates schedule data from all four major Belgian transit operators (STIB, TEC, De Lijn, SNCB) to compute optimal time-dependent itineraries including train, metro, tram, bus, and walking connections.

Finding the shortest path in a public transit network is fundamentally different from standard road network routing because transit networks are time-dependent: edges (trips) can only be traversed at specific departure times.

This engine parses General Transit Feed Specification (GTFS) datasets, models the national transit schedule into a searchable graph structure, and computes optimal travel routes based on departure time and user preferences.

• Multi-Agency Integration: Combines nationwide schedules from STIB (Brussels), TEC (Wallonia), De Lijn (Flanders), and SNCB (National Railway).
• Multi-Modal Routing: Seamlessly chains trains, metros, trams, buses, and computed walking connections between nearby stations based on geographic coordinates (latitude/longitude).
• Time-Dependent Shortest Path: Computes routes based on exact departure timetables rather than static travel times.
• Customizable Cost Functions & Preferences: Supports route personalization, including:
  • Penalty for specific transport modes (e.g., avoid buses, avoid metro).
  • Penalty for transfers (prefer direct routes over routes with many changes).

• GTFS Parsing: Ingests routes.csv, stops.csv, trips.csv, and stop_times.csv across all four agencies.
• Footpath Generation: Computes walking transfer arcs between spatially adjacent stops across different agencies using geographic distance.
• Scale: Processes millions of scheduled daily departures across tens of thousands of transit stops in Belgium.

• Java 24 JDK or newer
• Maven 3.6 or newer

• At least 4GB of available RAM (8GB recommended)

Build the project using Maven. Run the following command in the root directory of the project:

 mvn clean package

This will create an executable JAR file in the target directory.

Place the GTFS folder in the root directory of the project. The code is written specifically for the exact same names of files and folders that are found on UV website.

Your directory structure should look like this:

.
├── GTFS
│   ├── DELIJN
│   │   ├── routes.csv
│   │   ├── stops.csv
│   │   ├── stop_times.csv
│   │   └── trips.csv
│   ├── SNCB
│   │   ├── routes.csv
│   │   ├── stops.csv
│   │   ├── stop_times.csv
│   │   └── trips.csv
│   ├── STIB
│   │   ├── routes.csv
│   │   ├── stops.csv
│   │   ├── stop_times.csv
│   │   └── trips.csv
│   └── TEC
│       ├── routes.csv
│       ├── stops.csv
│       ├── stop_times.csv
│       └── trips.csv
├── pom.xml
├── README.md
├── src

You should increase the default memory allocation for java to at least 4GB. It is recommended to use 8GB for better performance if possible.

To do that you can put following argument after the java command when running the application:

For maximum heap size of 8GB, use:

-Xmx8g

For maximum heap size of 4GB, use:

-Xmx4g

Run the application using (Example with 8GB of heap space):

java -Xmx8g -jar target/STIB-1.0.jar [ Alveringem Nieuwe Herberg - Aubange - 10:30:00 ]

This is an example with values that were used in the assignment.

The basic command format is:

bash [departure stop - destination stop - HH:MM:SS] TRANSPORT_TYPE_EXCLUSION

Where:

• departure stop and destination stop are exact names of the stops as they appear in the GTFS data.
• HH:MM:SS is the time in 24+ hour format when you want to start your journey.

You can add the following options after the main command in any order, but they must be separated by spaces:

• METRO: Penalizes usage of metro lines from the route
• TRAM: Penalizes usage of tram lines from the route
• BUS: Penalizes usage of bus lines from the route
• TRAIN: Penalizes usage of train lines from the route
• CHANGES: Adds penalty for route changes (prefers routes with fewer transfers)

# Basic route search
java -Xmx8g -jar target/STIB-1.0.jar [BOILEAU - ARSENAL - 10:00:00]

# Exclude metro and prefer fewer changes
java -Xmx8g -jar target/STIB-1.0.jar [BOILEAU - JANSON - 10:00:00] METRO CHANGES

# Find route without using buses
java -Xmx8g -jar target/STIB-1.0.jar [BOILEAU - DELTA - 09:30:00] BUS