How do I change a zone’s speed factor?

How do I change a zone’s speed factor?#

A zone is a region of the walkable area that scales every agent’s desired speed while the agent is inside it. A speed_factor of 1.0 means “no change,” values below 1.0 slow agents down, and values above 1.0 speed them up.

Use set_zone_speed_factor(zone_id, factor) to update an existing zone’s factor.

import logging
from datetime import datetime

# Silence jupedsim-scenarios' INFO/DEBUG output. See the howto
# "How do I inspect a scenario?" for the full list of levels.
logging.getLogger("jupedsim_scenarios").setLevel(logging.WARNING)

print(f"Executed on {datetime.now().strftime('%d.%m.%Y, %H:%M')}")

Executed on 21.07.2026, 09:45

Load a scenario that already contains a zone, then list zones to find the id you want to change:

from jupedsim_scenarios import load_scenario

scenario = load_scenario("../assets/bottleneck-zone")
scenario.list_zones()

[{'index': 0, 'id': 'jps-zones_0', 'speed_factor': 0.4}]

Apply the change by index or by string id — both forms work:

scenario.set_zone_speed_factor(0, 0.5)                 # by index
scenario.set_zone_speed_factor("jps-zones_0", 0.5)     # by string id

Verify the change#

There’s no dedicated getter. Read the underlying dict to confirm the new factor:

scenario.zones["jps-zones_0"]["speed_factor"]

0.5

When to use this#

Zones are useful when you want a region-specific speed change without authoring a new geometry. Typical uses:

  • Stairs: slow agents to a realistic stair-climbing speed.

  • Narrow corridors: model a local slowdown without changing individual agent speeds.

  • Parameter sweeps: vary the factor across trials with run_sweep (see How do I sweep parameters?).