After developing, debugging, and calibrating an existing conditions model, no-build and build (alternative) models are created. These models are created from the existing model. No-build and build conditions can include optimizing existing signal timing plans; however, adding or modifying signal timing phases is considered an operational improvement alternative. There can be minimal changes to calibrated parameters in the model when developing future year models. However, use engineering judgement to confirm that new geometries and conditions in the future build years are represented realistically in the microsimulation model. Some elements maintained between models are driving behaviors, terminal conditions, and lane change distances. See

Figure 13-8

for a flowchart of the different aspects of both no-build and build model development.