I don't know if I missed all of them the first play-through or if they added them back in with a patch, but I'm now finding cars that blow up in New Vegas.  I had one cripple both of my arms when it blew next to me after Legion assassins jumped us the other night. 

I think all of the ones in the more populated areas are burned out, so I must have assumed all of them were that way.  I must have been extremely lucky to have not accidentally discovered even one in my first play-through.