Air carrier pilot reported a near miss with ground vehicle during taxi at DFW.

Narrative

Taxiing into Gate XX from Taxiway Golf; the CA was lining up on the taxi line and following DGS (Docking Guidance System) guidance; with wing walkers in place and carrying lighted wands; a crew-cab truck (make/model unknown); failed to stop on the terminal access road and came within ~15 feet of striking the moving aircraft. The CA was quick to slam on the brakes & stop the aircraft in time to avoid the truck. Ramp control was called immediately and started a search for the truck that was moving at an unsafe speed and not clearing for aircraft.Cause: We briefed the threat forward issues to include this one; holiday season; distracted ramp personnel (including us) and it likely saved an aircraft because; while we thought the truck saw the wing walker and was slowing down; in an instant; that changed. Only thing I can think of to help mitigate further risk at night; is to put a directional beam or some sort of pulsing light on the wing walker's wands at night to stop traffic. It cannot be a comfortable feeling for the wing walkers to stand in the roadway at night with a dimly lit wand to attempt to stop crossing traffic.