Transport registry¶

The transport registry defines how different public-transport modes are represented and how travel time is computed on graph edges.

It is used by all public-transport graph builders to validate transport types and to estimate per-edge travel time based on segment length, speed limits, and mode-specific parameters.

Overview¶

A transport registry is an instance of iduedu.TransportRegistry that stores one or more transport specifications (iduedu.TransportSpec).

Each transport specification describes:

the transport mode identifier (e.g. "bus", "tram", "subway");
technical maximum speed;
typical acceleration and braking distances;
a traffic slowdown coefficient.

The registry is consulted during graph construction to compute the time_min attribute for each edge.

Default registry¶

The library provides a predefined registry:

from iduedu import DEFAULT_REGISTRY

The default registry includes common public-transport modes such as buses, trams, trolleybuses, subways, and trains. These defaults are suitable for most use cases and require no configuration.

If no registry is explicitly provided, all public-transport graph builders automatically fall back to DEFAULT_REGISTRY.

TransportSpec¶

A single transport mode is described by iduedu.TransportSpec.

from iduedu import TransportSpec

bus = TransportSpec(
    name="bus",
    vmax_tech_kmh=90,
    accel_dist_m=220,
    brake_dist_m=140,
    traffic_coef=0.75,
)

The parameters have the following meaning:

name – transport type identifier, usually matching the OSM route=* value;
vmax_tech_kmh – technical maximum speed in kilometers per hour;
accel_dist_m – typical distance required to accelerate to cruising speed (meters);
brake_dist_m – typical distance required to decelerate from cruising speed (meters);
traffic_coef – traffic slowdown coefficient (values below 1.0 reduce effective speed).

Creating a custom registry¶

You can create your own registry and fully control how travel time is computed.

from iduedu import TransportRegistry, TransportSpec

registry = TransportRegistry()

registry.add(
    TransportSpec(
        name="bus",
        vmax_tech_kmh=80,
        accel_dist_m=200,
        brake_dist_m=120,
        traffic_coef=0.7,
    )
)

registry.add(
    TransportSpec(
        name="tram",
        vmax_tech_kmh=70,
        accel_dist_m=180,
        brake_dist_m=110,
        traffic_coef=0.85,
    )
)

All transport type names are normalized internally (lowercase, stripped).

Updating and extending the registry¶

Existing transport specifications can be updated:

registry.update("bus", traffic_coef=0.6)
registry.update("tram", vmax_tech_kmh=75)

Transport types can also be renamed:

registry.update("bus", name="express_bus")

If a transport type is encountered during parsing but is missing from the registry, it can be created automatically using ensure:

spec = registry.ensure("ferry")

This is useful when working with less common OSM transport modes.

Using the registry in graph builders¶

All public-transport graph builders accept a registry via the transport_registry parameter.

For example:

from iduedu import get_public_transport_graph

graph = get_public_transport_graph(
    osm_id=123456,
    transport_types=["bus", "tram"],
    transport_registry=registry,
)

If transport_registry is not provided, DEFAULT_REGISTRY is used automatically.

The registry controls:

which transport types are considered valid;
how per-edge travel time (time_min) is computed;
how short segments are handled (acceleration and braking effects).

API reference¶

`TransportSpec`	Configuration of a single public-transport mode used to estimate travel time on graph edges.
`TransportRegistry`	Registry of available public-transport modes and their specifications.