They're a weight saving measure! Buy mud flaps or carry around a bunch of dirt. Your call.

 

That's easily another 3 seconds in the quarter. Trust me. Seriously though, that's a lot of crap.

 

I'd be amazed if cars in Aus driven on regular roads saw so much accumulated dirt. IMHO, its the snow season when the snow sticks to the underside with the salt/dirt in it and then melts away leaving the insoluble dirt.

 

 

I'm not sure it'll work. The dirt was pretty heavy. Almost like all the light stuff got shook off with the bumps/vibration in everyday driving and the really heavy/dense stuff remained.

 

I get the same dirt buildup.