Dundee Traffic Department missing in action

Sir
Why does the Dundee Traffic Department not enforce the five-ton restriction on Willson Street between Beaconsfield and Union Street? The signs are clearly visible and have been in place for many years! A large number of heavy vehicles (including empty coal trucks operating away from the agreed coal truck route) traverse this section of Willson Street daily with impunity. Thousands of rands in potential traffic fines are being lost to the Municipal Revenue Account monthly due to the inability of traffic officers to police this law.
It seems that they are only focussed on time-expired parking meters in King Edward Street, escorting political visitors through the town and speed trapping, in the shade, in Glencoe.
Why is enforcement requiring some real effort beyond their capability?
Observer