How to Split Deliveries Across Vans by Capacity

Choose the unit that runs out first

Vans can run out of space, weight or both. Ambient grocery in roll cages usually runs out of floor space first. Drinks run out of weight surprisingly fast. Builders' merchants hit the payload limit long before the bed is full. Pick the unit that limits you most often, and record each order in it. If you deliver in cages, a cage count per order is far more useful than a value or a line count.

If weight and space both bite regularly, plan on the one that bites more often and check the other separately for the heavy days. One good unit, recorded consistently, beats two that are each half filled in.

Set usable capacity, not brochure capacity

A van that holds 26 cages on paper rarely leaves with 26. Leave room for loading order, returns and the odd extra order taken after planning. Many planners set usable capacity at around 90% of the theoretical figure and adjust from there. For a mixed fleet, set capacity per vehicle rather than one figure for all, because a single wrong assumption about the smaller van is how drops get left on the depot floor.

Why splitting by area alone keeps going wrong

The natural approach is to draw areas on a map and give each area a van. It works until one area has a heavy day. Then that van is overloaded while the next one has space, and the planner moves drops by hand, usually the ones on the boundary, which may not be the best ones to move. The underlying problem has a name, the capacitated vehicle routing problem, and it's hard because capacity and distance pull in different directions.

Signs your split needs work:

• The same round is over capacity most Mondays, or every week before a bank holiday
• Drops get moved between vans at the depot in the morning
• One van regularly comes back half empty while another needs a second trip
• Customers on area boundaries get a different driver every week

A manual method that holds up

If you split by hand, work largest orders first. Place the big drops, which are the hardest to move, then fill around them with smaller nearby ones. Track each round's running total against its van's usable capacity as you go, and when a round is full, move the drop that's closest to a neighbouring round rather than the last one you added. Re-check delivery windows for any drop you move, because a drop that fits by load can still be late on the new round.

How vRouted does it

vRouted splits the day's drops across your vans by capacity first, then optimises each van's round against delivery windows, drop times and the driver's shift and hours. Capacity is one number per van in whatever unit you choose, such as cages, crates, pallets or kilograms. Drops that can't fit on any van are flagged rather than squeezed in. For examples by sector, see drinks distribution, where weight bites first, and builders' merchants, where payload is the main limit. For the wider set of constraints, see optimising for multiple constraints.