The VS NEMA Wizard is a tool for designing intersection controls. The intersections can have a maximum of four legs, pedestrian crossings and emergency vehicle preemption.

It takes seven steps for a controller design. The NEMA Wizard exports a set of parameters, which can be imported into any controller running VS-PLUS on it.

This is like Java: the programs and parameters (here: the NEMA Wizard export) are interpreted by the Virtual Machine (here: VS-PLUS).

Normally VS-PLUS is a programming environment of its own. The NEMA Wizard generates a VS-PLUS program which restricts itself to the NEMA standard.

The seven steps are the following:

• Intersection: define the general intersection layout as the access roads and the main direction
• Phases: define the detailed phases (left turns, through traffic, pedestrians, priority vehicles)
• Overlaps: define the overlaps for right turns and pedestrian phases
• Phasing sequence: define the phasing sequence (lead and lag)
• Permissive periods: define the permissive periods (min, max and intergreen values)
• Detectors: define the detectors, if any
• Controller generation: generate the VS-PLUS control

The seven steps should be done in the mentioned order. It is always possible to jump back and forth to previous points.