ISO commercial auto rating, one vehicle at a time

A general liability risk is a business activity. A commercial property risk is a list of places. A commercial auto risk is a list of machines, and each machine carries its own rating facts.

Two trucks parked at the same yard, owned by the same insured, on the same policy, can rate differently because they are used differently. One runs local, one runs long haul. One is a light truck, one is not. The rate follows the unit.

That makes commercial auto the line where the schedule is most obviously the risk. A fleet of forty is forty rating problems that share a policy, not one rating problem with a count attached.

The consequence at the top of the funnel is that a commercial auto submission is never small. Getting a fleet quoted means getting forty rows of vehicle detail correct, and the difference between a platform you can build on and one you cannot shows up in three places.

Per-unit resolution. Each vehicle has to resolve from its own facts, not from an account-level assumption applied uniformly.

Visible roll-up. The path from unit premiums to policy premium has to be readable, because the first question anyone asks about a fleet quote is which vehicles are driving the number.

Consistency across the schedule. The carrier deviation and program pricing you released have to apply the same way to unit one and unit forty. You set one multiplier for the whole program and override the single state that differs, and every unit on the schedule resolves from that one released version.

SelectRate captures every rating step as the engine executes it, with the governing value and where that value came from, and every intermediate value is shown at the precision the engine used. Provenance records which filed mapping was selected, why it governed, and the document and page it came from.

A general liability worksheet for a single risk is one sequence of steps. A fleet worksheet is that sequence once per unit, then the steps that apply across the schedule, then the roll-up. So a commercial auto worksheet has to answer questions a monoline general liability worksheet never faces. Use them as the checklist when you review a fleet worksheet in a demo:

• Which vehicle a step belongs to.
• Which per-vehicle fact governed that step rather than an account-level input.
• Where the policy-level terms entered, and against what they applied.
• How forty unit results became one policy premium.

The full step-by-step reading of a worksheet sits on the general liability rating page. Commercial auto is the same discipline, repeated per unit.

One endpoint serves every rating channel you authorize, all on the version you released. Each API client has its own credential and is granted the specific programs it may rate. Scopes decide which operations a credential can call. Grants decide which programs. There is no wildcard at request time, and a client never sees another client's quotes or policies.

The Rating API is synchronous JSON on the same engine as Workbench, so identical inputs, program and effective date produce an identical premium and worksheet. Products are discovered rather than hard-coded: GET /products/{productCode}/schema returns field metadata, types, options, required fields and conditional visibility, and new lines of business appear through discovery without a contract change. For a line whose risk payload is as field-heavy as commercial auto, discovery is the difference between a schema change and a contract negotiation.