There are a number of changes between the previous (2007) version the current version (June 2015). These changes include:

• Consolidation of the Imperial and Metric versions into a single document with the limitation that units for a given rating system must be consistent (i.e., for a single test it is not permissible to use some stated metric criteria and some criteria that is converted from imperial to metric).
• Addition of new vehicle size rating classes (Full Size Sedan and Class 7 Cabover).
• Addition of 50 km/h [30 mph] rating for the Small Passenger Car and Pickup Truck.
• Removal of the P4 penetration classification from the rating system.