Tiers are similar to tags, categories, or labels, and can be possibly assigned to Drivers (optional), Pricing Rules (optional), and Corporate Accounts (mandatory).
Tiers are used to:
1) Filter out the list of drivers to whom the ride is dispatched (only in the case of dispatcher-posted ride with a Corporate Account Member passenger);
2) Filter out the list of Pricing Rules that will be used (only in the case of dispatcher-posted ride with a Corporate Account Member passenger);
Driver can have 0, 1, ... or all of the Tiers assigned.
Pricing Rule can have 0 or 1 Tiers assigned.
Corporate Account has to have 1 Tier assigned.
New Ride will only have a Tier associated with it, if the ride is for a passenger who has a valid Corporate Account PIN and it is entered in the ride request. Otherwise, New Ride will not have a Tier associated to it and available Drivers will not be filtered based on Tiers.