1. A system comprising: an acoustic excitation energy transmitter configured to directly couple an acoustic signal to a first tire of a first vehicle; a collector configured to receive attenuated acoustic energy transferred through said first vehicle from said transmitter to a second tire of said first vehicle; an analyzer configured to determine a first set of energy transfer characteristics of said first vehicle by analysis of said excitation energy and said received attenuated acoustic energy; a storage memory for recording said first set of energy transfer characteristics; and a comparator configured to produce a comparison of said first set of energy transfer characteristics with a second set of energy transfer characteristics, said second set comprising energy transfer characteristics collected from said first vehicle or from a second vehicle of a same make and model as said first vehicle.