Reactive consolidation does not attempt to influence the composition and timing of transportation movements. In turn, it reacts to shipments as they come in, combining individual orders to make one larger shipment for line-haul movement. An example of this is the USPS.
With proactive consolidation, the desire for shippers, carriers, and consignees can participate in consolidation savings. The shipper must take advantage of preorder planning, planning the quantity and timing, to apply for the consolidated large-haul. Multivendor consolidation is also a big part of the proactive style. An example would be perhaps a grocery store placing their orders on certain days with certain quantities. These orders are in anticipation of sales, and take advantage of vendor availability.