The Vehicle Information Service Specification (VISS) was begin as a joint effort between W3C and COVESA.  It is now a COVESA project.  It is a service for accessing vehicle information, signals from sensors on control units within a vehicle's network. It exposes this information using  COVESA Vehicle Signal Specification (VSS). The service provides this information in JSON format. The service may reside in the vehicle, or on servers in the internet with information already brought off the vehicle.

For detail please see the specification here on COVESA's GitHub.