iduedu.TransportSpec

class iduedu.TransportSpec(name, vmax_tech_kmh, accel_dist_m, brake_dist_m, base_speed_kmh, avg_wait_time_min=1.0, dwell_min=0.0)[source]

Configuration of a single public-transport mode used to estimate travel time on graph edges.

Each transport specification defines technical and operational characteristics of a mode (e.g. bus, tram, subway) that are used to compute per-edge travel time based on segment length, road speed limits, acceleration/braking behavior, and traffic conditions.

Parameters:
name

Transport type identifier, usually matching the OSM route=* value (e.g. "bus", "tram", "subway").

Type:

str

vmax_tech_kmh

Technical maximum speed of the vehicle in kilometers per hour.

Type:

float

accel_dist_m

Typical distance (meters) required to accelerate from standstill to cruising speed.

Type:

float

brake_dist_m

Typical distance (meters) required to decelerate from cruising speed to standstill.

Type:

float

base_speed_kmh

Free-flow speed of the mode in kilometers per hour: the speed it holds between stops once it is up to speed.

A road speed limit does not scale this value. Earlier versions made free speed affine in the limit, base + traffic_coef * limit, and fitting that form against published timetables showed the two terms are not separately identifiable: for buses, a fast base with a weak coefficient and a slow base with a strong one differ by less than a percent in error. Dropping the term outright improved accuracy for every mode measured (bus, tram, trolleybus, subway, commuter rail), because OSM’s maxspeed describes what a car may do, not what a bus with passengers, stops and traffic actually does.

The limit is still honoured where it binds: a vehicle is not modelled faster than the road allows.

Type:

float

dwell_min

Time lost standing at a stop, in minutes. Added once per segment. Defaults to 0.

Type:

float

avg_wait_time_min

Average passenger waiting time in minutes. It is assigned to directed boarding edges built from OSM data.

Type:

float

See also

https://iduclub.github.io/IduEdu/examples/transport_registry.html

Methods

travel_time_min

Compute travel time (minutes) for a single graph segment.

validate

Validate transport specification fields.
validate()[source]

Validate transport specification fields.

Raises:

  • ValueError – If a required field is missing or outside the supported

  • range. –

Return type:

None

travel_time_min(segment_len_m, *, speed_limit_mpm=None, min_speed_mpm=60.0)[source]

Compute travel time (minutes) for a single graph segment.

The method estimates traversal time using a simplified kinematic model that accounts for: - the transport mode technical maximum speed; - an optional road speed limit, entering the free-flow speed affinely; - time lost standing at a stop (dwell_min); - time lost on acceleration and braking.

For short segments where the vehicle cannot reach cruising speed, a reduced peak speed is assumed and the segment is traversed using an acceleration-deceleration profile without a cruising phase. The peak speed scales as sqrt(L / span) because under constant acceleration the distance covered grows with the square of the speed reached; the two branches meet continuously at L == span.

Parameters:

  • segment_len_m (float) – Segment length in meters. Must be positive.

  • speed_limit_mpm (float | None) – Optional road speed limit in meters per minute. If provided, the effective speed will not exceed this value.

  • min_speed_mpm (float) – Lower bound for effective speed (meters per minute), used to avoid unrealistically large travel times on very short segments.

Returns:

Estimated travel time for the segment in minutes.

Return type:

float