In a concrete drive way should I use fiber mesh, rebar or both? Slab will be 4" thick 35x30..

A recent trend is to use rebar with fiberglass fiber in the mix. You can also get steel fiber. Is this a 30X35 driveway or parking pad? Sounds like a heavy load area. Yes?

In addition to mesh or rebar you need ground prep. Tell us the weights that will be sitting on or traveling over this big driveway. Excavation, gravel and tamping mat be as important as using rebar.

I have constructed, and demolished all types of concrete slabs including rebar, poly and steel fibre reinforced, and welded wire mesh. By far, the best way to reinforce concrete is with rebar, and a slight over kill is 10mm rebar at 16"OC. The bar should be chaired off the base, but still be in the lower 1/3 of the slab if possible.
The next best choice is welded wire mesh, and it is economical, and easy to install. Generally you pull this wire up after initially pouring concrete, and try to get it in the lower half of the slab if possible. Be very cautios not to have it too close to the surface, as your tool cuts will hit the wire and "bounce" leaving a cosmetic blemish.
Fibre reinforced concrete is undesirable for am exterior broom finished slab, as the brooming will leave pulled fibres on the surface.