About

Commonly asked questions.

What is RDI?

The quality of the connection between two points can be expressed in terms of the Route Directness Index (RDI). RDI is the ratio of the straight-line distance “A” (“crows flight”) to the actual route distance “B”. RDI values closer to 1.0 represents a relatively direct connection between two points; RDI values closer to 0.1 represent in-direct connections on circuitous routes.

For example, RDI  can be calculated for every home in a neighborhood, meaning from every home to every home. Each home would have an average RDI score, representing how well that home is connected to every other home in the neighborhood.  Other examples are the quality of walk-to-school routes, or the quality of connections to transit stops.

What is RDI Desktop?

Using new GIS software, developed in coordination with ESRI, Transpo Group has automated the RDI calculations for city-wide applications or neighborhood-level analyses. This also allows for convenient “what-if” project analyses or intuitive project prioritization metrics. At this time, RDI Desktop software solutions are only available as part of the Transpo Group’s transportation planning services.