Scenarios

Structure of a scenario

A scenario can be composed of:

• One or more situations.
• One or more Key Performance Indicators (KPIs).

A situation is made up of one or more events.

KPIs involved in a specific scenario can be linked to the events described in a specific situation or can be associated to other traffic network attributes.

Event objects and scenario KPIs can be used to enable, disable, or modify the behavior of a specific simulation.

Simulation structure

A simulation can contain one or more scenarios. If a scenario is active in a simulation, all events and KPI associated to that scenario become active.

For example, in a real-time environment, scenarios may be used to trigger some network settings that would otherwise not be active, such as an extraordinary limited traffic zone closure.

Simulation groups and parallel simulations

A simulation group is a set of associated simulations from the same time period: for this reason, they are generally referred to as parallel simulations.

One of the simulations is used as a reference: it is called the base simulation.

A group of parallel simulations are mutually compared to get useful information.

When combining parallel simulations with scenarios, you can compare alternative control actions, such as alternative contingency signal plans.

Parallel simulations are performed in the Optima real-time environment. The alternative simulations spread from the same instant of the base simulation, but with different scenario settings. The base simulation generally refers to the real state of the network in the standard scenario.

Scenario workflow

To simulate a scenario, you need to perform the following actions:

1. Create the scenario:

   → Creating a scenario.

2. Get the ID of an existing scenario:

   → Getting the details of a scenario.

3. Create a simulation group that contains a list of all simulations and of the related scenario to be evaluated:

   → Creating a simulation group.

4. Trigger the simulation group and wait until the simulation has finished:

   → Starting a simulation.

5. Get the results of all simulations of the simulation group:

   → Getting traffic forecast.

Topics in this section