The novel mathematics underlying the technique is described in our patent US 8249810 B2 which introduces the concept of a "Plateau" or "Daichi" that efficiently identifies good geographical routes in one pass.
The set of Choice Routes™ help to eliminate the surprise when the single best route changes because of traffic or map updates, as the same routes still appear, perhaps in a different order. The driver might choose between these diverse routes based on personal knowledge, familiarity, or a desire for a faster or more fuel efficient route on the day.
In the case of severe disruption, we offer both local and distant diversions. At times of low traffic, local diversions are preferable, but at high traffic volumes, it is best to stay well away from the disruption.
Using Choice Routing™ (CR), we have three ways to incorporate properties such as weather into the route computation:
Some complex properties such as the placement of rest stops cannot be optimised in the trees, so CR gives a powerful way to evaluate them rapidly over a set of good routes.
Our implementation of intermodal routing combines road and public transport journey planning in novel ways.
The aim is to present a set of options for completing a journey that involve anything from no driving stage to driving all the way, but including interchange from driving to public transport (PT) at local stations (e.g. kiss-and-ride), intermediate, or distant stations (park-and-ride).
We do this partly by recognising that time has a different value when spent driving, or spent as a passenger. Also, we use lessons from Choice Routing™ to offer plans that are diverse in their use of the roads and of the PT network, for example, by selecting journeys with different interchange points and different train lines where possible.
The framework for this is built over existing road and PT routers, and is flexible enough to include trains, buses, cycling and walking, as well as weighting solutions based on the parking options including expected occupancy and fallback plans where available.
We can compile maps from Here, TomTom and OpenStreetMap for use with our router. Route quality is similar, although always improved by the provision of historical speed data.
The router GUI uses the Document/View architecture to open multiple views on multiple maps.