Can my car be so dirty that it becomes non-roadworthy?

Question:

I recently captured a photo of this vehicle driving by on the M1 in Johannesburg. [I was in the passenger seat leaning to right  – just in case you want to comment about taking photos while driving] The number plates were not visible. Is this transgressing the Rules of the Road?

Answer:

The car itself is not regulated if it is dirty, but a person may be charged in terms of reg 35 if the numberplate and number on it is not visible.

Regards
Alta

Also view on windscreen safety:

Cracked Windshield, Safe Driving and the Law