Is it possible to assign an english design standard to a metric model?

My model file is in metric, but the design standard I want to utilize is in english units. I'm trying to determine if my geometry meets AASHTO design standards for a 25 mph road. My project is in the states. I have access to the Indian and UK standards. If anyone knows of the appropriate metric design standard I should utilize in place of the AASHTO design standard mentioned above, then I would appreciate the information.