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Mesoscopic Pedestrian Simulator

The mesoscopic pedestrian simulator becomes active whenever a dynamic transit assignment is enabled. Its simulations are simpler than those carried out by the microscopic simulator and it is designed to handle the fast-paced, large-scale dynamic simulations usually featured in mesoscopic projects.

The main points of interest and contrast between meso and microsimulations when considering pedestrians are discussed below.

Walking Behavior

Pedestrians in mesosimulations do not walk across pedestrian areas. Instead, they use the road network as their walkable area, moving across sections and nodes.

A pedestrian inside the network can move along the sidewalk of any section when following its path to a destination. If their chosen shortest path includes transit, they can visit a transit stop and wait to take a transit vehicle.

Using the road network does not imply directionality, so pedestrians are free to move upstream or downstream in respect to the flow of vehicles in a section.

The pedestrian type can be restricted by road type, so that some pedestrians are not allowed to walk on or through specified parts of the network. This is useful when modeling highways or train tracks where pedestrians are usually forbidden.

This current simplification of the model assumes that pedestrians travel with a speed equal to their pedestrian type's desired speed and do not encounter collisions or restrictions to flow while walking.

Note: Disconnected areas of the road network cannot support pedestrians and will not be included in pedestrian paths. In such cases, a warning message will be displayed.

Pedestrian Centroid Connections

Pedestrian centroids can be defined at any place inside the network area. For mesoscopic walking logic to work, these centroids must be connected to a section on the road network. This connection is made automatically by the simulation when it begins. The connection is made to the closest road section that is walkable by pedestrians. You need to take this into account when evaluating trip outputs because the position of the centroids can ultimately change the outputs if the connection changes.

Behavior of Transit Stops

Pedestrians whose path uses a transit segment will walk toward their next transit stop and wait there for a vehicle of the chosen transit line to arrive.

Regarding the arrangement of doors in transit vehicle types, transit vehicles need to have at least one valid door to allow boarding and at least one valid door to allow pedestrians to alight (this can be a single combined exit/entrance door). If this is not the case, the transit vehicle type is incorrectly formed for dynamic transit assignment and will not be able to serve any of the transit stops. For more information about transit vehicle doors, see Vehicle Types.

Upon arrival at a stop, the transit vehicle will first calculate which pedestrians from the current load should alight. Then it divides them into equal parts to distribute them between the available exit and combined exit/entrance doors. It will use the stop's alighting time as a ratio for each door and compute how much time it needs to allow all pedestrians to alight.

Next it will board pedestrians that need to use this vehicle's transit line, up to its maximum capacity. To determine the time to spend boarding these pedestrians it will consider whether they will enter through an entrance-only door or if they will enter by an exit/entrance door.

In the first case, the boarding time from the stop is used as a flow for each door and the time is computed counting from the vehicle's arrival at the stop. In the second case, pedestrians must wait until alighting is completed to start boarding, thus adding time to the total stop time.

When a transit vehicle has a mixture of entrance-only and exit/entrance doors, the maximum number of pedestrians will use the entrance-only doors as the stop's boarding flow while waiting for those alighting. Then the remaining pedestrians will use all the available doors to board. We do this to ensure that the stop time of the vehicle is minimized.

Please be aware of the following three aspects of this logic and how they interact with the mesoscopic simulator.

  • Transit vehicles do not comply with stipulated dwell times in a timetable: once boarding and alighting is finished, they depart.

  • Only pedestrians that have already reached the transit stop before the vehicle arrives are considered candidates for boarding. A pedestrian that arrives in-between the opening and closing of doors cannot board and must wait for another transit vehicle to arrive.

  • Transit stops in mesoscopic simulations are considered as being placed at the very end of their section. This fact affects the walking times, travel times, and distances of pedestrian trips.