A B757 Captain explained the lax; dangerous and uninformed behavior of Ground Service personnel at MIA.

Narrative

After nosing into self-parking gate at MIA the aircraft was stopped due to several pieces of equipment across the yellow equipment clear lines. Several items were moved but the ground crew were very befuddled about the positioning of a portable electric cart. They moved it only a few feet leaving it well within the lines so that it would have disappeared partially under the right side of the aircraft's nose if we were in the final parking position. Eventually someone from another area came and moved it outside the lines. This process took 7 minutes and indicated to me that the ground crew was either unaware of or unwilling to comply with the equipment positioning requirements. Additionally; numerous vehicles zipped between the aircraft's nose and the gate while the area was being cleared. The real hazard was observed when; upon stopping in the final parking position; a truck pulling a baggage cart immediately zipped into view in front of the aircraft. To get to that position at that time the driver had to have driven under the right wing and adjacent to the right engine intake (which was running) even as the aircraft was still moving. This individual then began the task of servicing the potable water. I made a request to operations to meet a Ramp Supervisor at the gate (I was taking that aircraft on the next flight) but no one ever identified themselves to me. You can track this problem all you want but it will not solve the problem. If you want to know how bad it is in MIA I would suggest you see for yourself. Finally; lack of yellow lines below the fixed position jet bridge are lacking.