1. At the vehicle’s exit time from the meso area, calculate travel time using the delay functions;
2. Add one vehicle to the volume of the sections traversed;
3. Move vehicle to destination OR to next mesoscopic area.

How to create a hybrid macro-meso experiment

Within a dynamic scenario, you can create a hybrid macro-meso experiment in a similar way to creating a hybrid meso-micro experiment.

1. Draw a polygon around each area that you would like to simulate at a mesoscopic level
2. Convert the polygon to a simulation area
3. Create a new hybrid macro-meso experiment within an existing dynamic scenario
4. In the Hybrid tab of the new experiment, add your polygon(s) to specify the mesoscopic areas

Draw a polygon, right click and click convert to simulation area

The polygon will then go green to show it is a simulation area

Cost alignment

As the path cost is the sum of the macro cost and the meso cost, it is essential that the units of the macro and meso cost functions are aligned. The default macroscopic cost is expressed in minutes, whereas the default mesoscopic cost is expressed in seconds. To align the cost, you can specify the conversion in the hybrid macro/meso experiment, using the VDF/TPF/JDF Unit Conversion Factor.

It is a good idea to check that the functions that you have used are the same format as the generalized cost function. For example, you may need to add in toll costs, value of time and vehicle operating costs with the same coefficients.

If you want to get skim matrices with any function components, you’ll also need to ensure that they are defined both in your macroscopic functions and in your mesoscopic functions.

Travel time in the macro area

The travel time in the macro area specifies how long it takes for a vehicle generated in the macroscopic area to reach the boundary of a mesoscopic area. The default is Total VDF/TPF/JDF cost, which interprets the overall output of those functions as a pure travel time; if you have added other terms and computed a generalized cost, you should define and choose a function component that provides the travel time only.

If you developed your demand by using a cordon around the mesoscopic area, you should choose instantaneous time for the first and last segment. This is because the time of each demand slice represents the time at which incoming trips cross the boundary of the mesoscopic area rather than the time when they departed from their origin.