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New Features in Aimsun Next 26

This chapter summarizes the main new features in Aimsun Next 26

Aimsun Next 26: Highlights

The most significant additions to Aimsun Next 26 include the following:

  1. Collaboration between users via the new Geo Comment object
  2. Changes to the Check And Fix
  3. New entry-based calculation for speed, travel time, delay time, count and flow in dynamic simulations
  4. New merge model in micro
  5. Improved cooperation model in micro
  6. New off-ramp behavior in meso
  7. Skim Matrices now available as an output for Dynamic Experiments
  8. Random seeds internal management improvement for Demand and Transit Vehicles generation
  9. LOS calculation updated for urban segments
  10. Relative Gap Matrices now available as an output for Static Assignments and OD Static Adjustments
  11. Redesign of the Welcome Window

Other improvements available in Next 26 are:

  1. Dynamic Cost functions have been unified
  2. New parameter Use Travel Times from the Input Path Assignment Plan for All Vehicles in Hybrid Macro-Meso experiments
  3. Travel Time change in Hybrid Macro-Meso DUE experiments
  4. New Traffic Management action: Periodic Call
  5. Centroid Groupings are now allowed as Origin and Destination for Traffic Management actions
  6. Traffic Management Policies and Conditions new trigger options
  7. Empty Path Assignments can be included in a Path Assignment Plan
  8. New Static Assigned Percentage and Number of Passengers contents in Real Data Sets
  9. Four-Step Model Experiment improvement for connection settings visualization
  10. Parameter to control the maximum number of multi-routing options considered in the Transit Assignment
  11. New option: Allow 'None' in Object Type attributes
  12. New Controller Interface: Swarco ITC-3
  13. New Controller Interface: SEPAC M60
  14. SRM messages added to Yutraffic controllers
  15. New parameter Timeout for Yutraffic controllers
  16. New parameter Train Length for OCIT R09 Telegrams
  17. New version of Python for scripting and APIs: Python 3.12

User Interface

  • The Welcome Window has been redesigned to have in a single place access to recent open projects, new projects as well as all the Aimsun Learning Resources and the Aimsun News.
  • Users can now create a chain of geo-referenced comments shared by all ours with access to the project documents. They are stored in the cloud and shared among all files belonging to the same myAimsun Project. A Geo Comment is a marker that can be placed on the map and contains user comments.
  • Real Data Sets include now two more variables that we can read content for:
    • Static Assigned Percentage which might be relevant for turn, supernode trajectories and subpaths real data.
    • Number of Passengers relevant for comparing real data with the transit assignment time series output that contains the total number of passengers that used a specific line.
  • Now you can add Path Assignment Items that have not been calculated yet - the sole requirement is that they are already assigned to a replication/result/macro experiment to store Path Assignment outputs, so that initial time, duration (and route choice interval for DUEs) are known.
  • A new checkbox Allow 'None' has been enabled when adding a new attribute or column to an object, when the Data Type is Object. This sets whether the field can be left empty or not.

Check And Fix

  • Changes to the Check And Fix editor:
    • Check And Fix messages are persistent. When the dialog is opened, instead of checking the network, the messages are read from the cloud.
    • After running a Check And Fix, old warnings and errors no longer present will be marked as fixed.
    • Check And Fix messages can be marked as ignored so that they are hidden by default.
    • Comments can be added to Check And Fix messages.

Dynamic Simulators

  • In previous releases of Aimsun Next, the dynamic simulation outputs were considering the vehicles that had exited each simulation object (i.e. a section, turn, or the entire network) during a given statistical interval. These metrics reflected the performance experienced by vehicles that completed their journey through the object within the interval. In Aimsun Next 26, new entry-based statistics, that include both the vehicles that have exited the simulation object and those still inside it at the end of the statistical interval, have been added. This approach provides a more comprehensive view of the traffic conditions by accounting for in-progress journeys.

  • Adding or deleting a centroid or a transit line will no longer affect the results of the simulation. Individual internal random seeds are generated per OD pair and transit line in order to guarantee this.

  • Improvement of the vehicle behavior when two lanes are merging into the same lane in microscopic simulations.
  • The microscopic cooperation model at both on-ramps and merges has, in addition to the cooperation by creating a gap, a new cooperation by changing lane parameter that makes the cooperating vehicle leave the lane that the merging vehicle will use.
  • Off-ramps in mesoscopic simulations apply now the same lane selection model as nodes, in which vehicles spread among the connected target lanes uniformly.
  • In Hybrid Macro-Meso experiments a new parameter has been added, Use Travel Times from the Input Path Assignment Plan for All Vehicles, that defines whether the cost of the vehicles in the macro part should use the travel times from the Scenario's input path assignment plan or the (default) cost being calculated by the actual experiment's route choice method.
  • In Hybrid Macro-Meso experiments with DUE, the macro travel time that will be taken into account will proceed from the same slice, previous iteration (instead of the same iteration previous slice as in previous versions).
  • In dynamic simulation there is no longer a need to distinguish between initial and dynamic cost functions, nor between by vehicle type or not. Now only the type 'dynamic cost function' is considered, and it will access initial or simulated travel times, by vehicle type or not, depending on the data available and the function definition.
  • Skim matrices can now be a default output when running a dynamic simulation. The option to retrieve them later on is also now available and to calculate the average skims from an average of replications.
  • The calculation for LOS (Level of Service) in urban sections has been updated, based on new parameters in the section's editor that the user can fill in.

Traffic Management

  • In Traffic Management Policies and Traffic Conditions that are activated and deactivated by triggers offer now two new options:
  • The activation trigger can be defined by period, thus changing the conditions that need to be met depending on the time.
  • The actions can be activated for a minimum amount of time. The deactivation trigger will be considered only after this time has elapsed.
  • A new Traffic Management action is now available. The Periodic Call action will emulate random calls in a detector.
  • The following actions in Traffic Management now allow selecting a Grouping of Centroids as the Origin and/or Destination.

External Controllers

Static assignment and adjustment

Transit Assignment

  • For the Transit Assignment with Multi-Routing, a new field has been added in order to limit the number of paths to be considered in a transit strategy, improving the assignment calculation time.

Four-Step Model

  • In the four-step model experiment, when selecting a connection between diagram boxes to define the content that is passed through, filtering and ordering options have been added, to make this selection easier.

Previous Fast Track Features

Aimsun Next 26 also includes the following features or improvements that were released as Fast Track features in previous releases of Aimsun Next 24 as well as enhancements launched after Next 24 Final Release:

  1. Improvements in priorities in supernode trajectories
  2. Improvement for the cell selection in the OD Matrix editor
  3. New Vehicle Type parameter for microsimulations: Can Be Overtaken
  4. Performance Improvement for PT and Static Adjustment
  5. SIDRA interface updated to SIDRA 9.1

Static assignment

User Interface

  • In the OD Matrix editor, Cells tab folder, the corresponding row in the matrix will be selected when clicking on a centroid in the 2D View. Use Ctrl+Click when selecting the centroid on the 2D view to select the corresponding column.

Microscopic Simulator

  • In the Vehicle Type editor, under the Microscopic Model tab, Two-Way Overtaking Model subtab, a new checkbox has been added: Can Be Overtaken, that sets whether the vehicles of that type can be overtaken or not when driving on sections that allow two-way two-lane overtaking.

Static OD Adjustment

  • Improved performance in assignment matrix creation during outer iterations.

Transit Adjustment

  • Improved selection of sparse/dense matrix for adjustment output matrix based on the percentage of empty cells.

Scripting and Programming Interfaces

  • Next 26 comes with Python 3.12 as the version to use for running scripts and APIs in Python in all platforms (Windows, Mac ARM and Ubuntu 24). The Qt version is Qt6.

Signal optimisation interfaces