Division 3.1.3: The damping is critical when C = Co - Commission Regulation (EU) No 1230/2012 of 12 December 2012 implementing Regulation (EC) No 661/2009 of the European Parliament and of the Council with regard to type-approval requirements for masses and dimensions of motor vehicles and their trailers and amending Directive 2007/46/EC of the European Parliament and of the Council (Text with EEA relevance)

where:

Co = 2 \sqrt{KM}

The damping ratio as a fraction of critical is C/Co.

Division 3.1.3 The damping is critical when C = Co