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Public Transport

The Public Transport Routing in GOAT is essential for performing analyses that include public transport trips.

1. Objectives​

Public transport routing facilitates intermodal analysis by integrating access and egress modes, such as walking, cycling, or driving to and from the station. This is more complex than the other routing modes as it requires the merging of different datasets (such as sidewalks & bike lanes, public transport stops & schedules, etc.) and calculation approaches.

Public transport routing is used for indicators such as Catchment Areas and Heatmaps in GOAT.

2. Data​

Transit Data​

Utilizes data in the GTFS (General Transit Feed Specification) format for static public transport network information (stops, routes, schedules, transfers, and more).

Street Data​

Incorporates street-level information from OpenStreetMap to support multi-modal routing and real-world path connections (includes sidewalks, bike lanes, and crosswalks).

3. Technical Details​

A public transport trip consists of three legs: an access leg from the origin to a PT station, the transit leg through the PT network, and an egress leg from the PT station to the destination. The access and egress modes can be configured independently.

PT trip structure and example combinations

Public transport routing is performed by GOAT's own high-performance routing engine, which wraps the open-source nigiri library. Nigiri is a C++ library from the MOTIS project that provides one-to-all public transport connection search using the RAPTOR algorithm.

The transit leg is computed by nigiri, while the access and egress legs (first and last mile) use GOAT's own Dijkstra implementation — the same routing used for active mobility and car. This keeps street-level routing consistent across all transport modes.

Routing Options​

Modes​

Analyses for the following modes of public transport are currently supported by GOAT. Choose between one or more, keeping in mind that some modes may not be available in all regions.

bus tram rail subway ferry cable_car gondola funicular

Travel time limit​

The maximum journey duration to consider for public transport routing. A maxium of 90 min is currently supported. This includes the time spent during access and egress from public transport stations.

Day​

The day of the week to consider for public transport routing. Choose between Weekday, Saturday and Sunday. This is useful for evaluating changes in service between weekdays and weekends.

Start and End time​

A time window for public transport routing. The engine evaluates every departure minute within this window and keeps the fastest journey to each reachable location — it is not an average over the window. The result is therefore the best-case, largest possible catchment area from your specified origin point. A journey is considered to fall within the time window solely based on its start time, regardless of its end time or duration.

Maximum transfers​

The maximum number of transfers a PT journey may include. A maximum of 5 transfers is supported.

Access and Egress​

The access leg (origin to the first PT station) and the egress leg (last PT station to the destination) are configured independently. For each, you can set:

  • Mode — how users travel to and from the stations: Walk, Bicycle, Pedelec, or Car.
  • Calculate by — whether the leg is limited by Time or Distance, and the corresponding Limit.
  • Speed — the travel speed used for the leg (when calculating by Time).

By default, both the access and egress legs use Walk, a Time limit of 15 min, and a speed of 5 km/h.