Figure 2
The network diagram consists of a central rectangular node labeled “0” surrounded by circular and octagonal nodes. A legend on the right is titled “Nodes” and identifies circular nodes as “Customer”, octagonal nodes as “Customer acting as consolidation point”, and the rectangular node with “0” as “Depot”. The legend for “Routes” shows a dashed arrow for “No vehicle-type change” and a solid arrow for “At least one vehicle-type change”. The “Vehicle types” legend includes an orange line for “Type 1”, a green line for “Type 2”, a red line for “Type 3”, and a blue line for “Type 4”. The nodes and connections are as follows: At the top left: A dashed black arrow labeled “4” begins from circular node “21” and connects to circular node “3”. From circular node “3”, a dashed black arrow labeled “4” connects to the central rectangular node “0”. To the left: A red solid arrow labeled “3” begins from circular node “5” and connects to octagonal node “24”. A blue solid arrow labeled “4” begins from circular node “4” and connects to octagonal node “24”. From octagonal node “24”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. On the far left: A dashed black arrow labeled “3” begins from circular node “20” and connects to the central rectangular node “0”. At the bottom left: A red solid arrow labeled “3” begins from circular node “1” and connects to octagonal node “23”. A red solid arrow labeled “3” begins from circular node “16” and connects to octagonal node “23”. From octagonal node “23”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. At the top center: A red solid arrow labeled “3” begins from circular node “19” and connects to octagonal node “13”. A blue solid arrow labeled “4” begins from circular node “9” and connects to octagonal node “13”. From the octagonal node “13”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. At the bottom center: A red solid arrow labeled “3” begins from the circular node “15” and connects to the central rectangular node “0”. Below this, a red solid arrow labeled “3” begins from circular node “2” and connects to circular node “18”. From circular node “18”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. To the top right: A red solid arrow labeled “3” begins from circular node “8” and connects to octagonal node “7”. A green solid arrow labeled “2” begins from circular node “12” and connects to octagonal node “7”. A green solid arrow labeled “2” begins from circular node “6” and connects to octagonal node “7”. From the octagonal node “7”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. At the bottom right: A dashed black arrow labeled “4” begins from circular node “11” and connects to circular node “10”. From circular node “10”, a dashed black arrow labeled “4” connects to the central rectangular node “0”. An orange solid arrow labeled “1” begins from circular node “22” and connects to circular node “14”. From circular node “14”, a blue solid arrow labeled “4” connects to the central rectangular node “0”. On the far bottom right, a dashed black arrow labeled “4” begins from circular node “17” and connects to circular node “25”, and from circular node “25”, a dashed black arrow labeled “4” connects to the central rectangular node “0”.Arc structure with assigned vehicle types and consolidation points