There is only one file type that uses the .OVH extension:
OMSI Vehicle Configuration File
File created by OMSI The Bus Simulator, an omnibus driving simulation program; similar to other OMSI configuration files like .HUM, .SLI, .SCO, and .BUS files; holds configuration data for vehicles, such as their appearance, that interact on the road with the bus during gameplay; can be customized.
The OVH file is made up of lines of data following a keyword (whether it's for a script or description). The format looks like this:
OMSI will only read lines of data that are in this format.
|MR Software OMSI The Bus Simulator 2||Paid|
Updated: April 7, 2014