Hi,

Here are the answers for you:

Is the speed in vehicle locations KPH or MPH?

speed in vehicle locations is in KPH.

What does the vehicle location call_name refer to?

call_name refer to how the agency staff refer to the vehicle.

Can you provide information about the extent of identifier matching with the GTFS data?

The IDs does not match the GTFS data. Things like route name, short name, stop code, etc should match in most cases.

Can I expect the service stopID to match with the GTFS stop_id?
Is the stop_id and stop_code in the GTFS always going to equal?

We don’t provide GTFS data, please see the official documentation for GTFS related questions.

Are all attributes in the sample responses required or optional? I need to know that to be sure the app won’t stop working if an attribute on occasion isn’t included.

I believe all attributes are required, if they don’t have a value, they will simply be set to ‘null’. But it’s probably a good idea to check if the values exists to make sure your app don’t crash.

In vehicle locations arrival_estimates, is there a way to tell which agency the stop_id is for?

You should be able to use the “stops” feed and “routes” feed to find out the agency. Or you can filter the arrival_estimates by agency_id.

Thanks for using TransLoc OpenAPI.

Stu