Fleet Routing with the VRP Solver: An Introduction

Do you have a fleet of vehicles that need to be routed to customers?  The Vehicle Routing Problem (VRP) Solver is here to help you do that efficiently. But the VRP Team understands that the solver is complicated and has a ton of different options.  This is the beginning of a series of posts to help explain the different modeling options available to you, giving you all our best tips and tricks.  We will start our discussion by examining what problem types we support.

If you have topics you would like us to discuss or specific questions please post them here.

Services

The vehicles visit customers to provide a service.

In the Services operation, the vehicles all start at either a central location or the driver’s residence. It then visits the customers on the route providing a service for them before moving on to the next customer. The vehicle then returns to either the central location or their residence to end the day.

• An exterminator visits houses for treating various pests. Specialties are used to describe which chemicals are kept on the vehicle.
• Mechanics visit businesses to fix elevators/escalators or provide preventative maintenance to the motor.
• Health Inspectors are sent to Hospitals, clinics, restaurants, etc. to determine the cleanliness of the business.
• A satellite/cable provider sends their installers out to customers to install new equipment, recover equipment from customers that are leaving, and making repairs or adjustments to existing customers.
• Utility workers are sent to houses at the end of the month to notify them they have not paid their bill and will have the utility shut off unless it is paid immediately.
• City workers are given work requests around town to fix things such as street lights.
• An insurance company sends out claims assessors to take pictures and talk with the customers after a natural disaster.

Goods-Delivery

Vehicles deliver goods from a central location to customers.

In the Delivery operation, the vehicles start their routes full from their warehouse.  They deliver their goods to customers along their route, emptying their vehicle as they go. Vehicles end their route empty at the last location returning to the warehouse.  There is also the option of having the vehicle return to the warehouse mid-route to fill up the vehicle for more deliveries.

• A store delivers furniture, appliances, large electronics, etc. to customers.
• Medical supplies are delivered to hospitals and clinics to resupply their stock.
• Food and drink merchandise is delivered to grocery and convenience stores.
• A retail company delivers its latest line from the manufacture facility to the stores.
• A furniture store that delivers may need to send the trucks out for more than one trip in a single day. All of the items to be delivered cannot be loaded at the start of the route.
• The Meals on Wheels drivers deliver three to four meals at a time. They then go back to the cafeteria to pick up more.  This insures the food is still warm on delivery.

Goods-Pickup

Vehicles pickup goods from customers bring them back to a central location.

In the Pickup operation, the vehicles start their routes empty and get filled up along the route. They then arrive full at the ending location.  There is also the option of the vehicle to return to a central facility to empty their vehicles mid-route and then continue picking up items.

• A non-profit organization that accepts donated goods visits homes to pick them up.
• A collective farm company goes to the local farms to pick up fresh produce for selling each morning.
• A recycling company picks up large electronics from customers to bring back to the warehouse to break down for scraps.
• A Hazmat company goes around to sites to pick up hazardous material needing to be properly disposed.
• An automobile parts junkyard sends tow trucks to residences to pick up cars that can no longer run. This needs to be a tow truck that carries more than one car at a time. The tow trucks make several trips back to the junkyard to drop off the cars that have been picked up.

Goods-Delivery and Pickup

Each Vehicle can both deliver goods from a central location to a customer and/or pickup goods from a customer to bring back to the central location.

In a Delivery and Pickup operation, the vehicles start their route at least partly full to make deliveries.  The vehicle can also pickup product along the route when the vehicle has extra room from either a partially full vehicle at the start or as goods are delivered freeing up space. Pickups, however, do not re-fill the vehicle with usable goods allowing it to make more deliveries.

• A parcel delivery company delivers mail to customers and picks up their outgoing letters and boxes.
• A store delivers new furniture, appliances, electronics, etc. to customers and removes their old product to take back to the store to be refurbished, recycled, or donated.
• A portable toilet company has truck routes that deliver portable toilets from their depot to customer sites. These same routes also pick up toilets to take out of service and bring them back to the depot.
• A Chemical company delivers barrels to various oil drilling wells and picks up the empties to return to the plant.

Courier/Rideshare

Vehicles Pick up a customer or packages from one location and deliver them to another location.

In the Courier/Rideshare operation, the vehicle always starts empty. The passengers or parcels are picked up along the route and transported to their desired drop off location. The vehicle then ends the day with no passengers or parcels.

There can be additional rules about the maximum time between the pickup and delivery orders, especially when transporting people.  This may lead to having customer service related objectives.

• A courier company picks up packages and delivers on demand for their customers. Sometimes there is a time window for deliveries.
• A para transit company provides transportation to senior and disabled citizens. In order to provide good service, they limit the additional ride time any particular individual will do above and beyond their individual trip.
• Special needs school transportation provides door to door transportation to students that qualify. State regulations say that any student cannot be on the bus more than 60 minutes.
• An armored truck service that picks up cash from local businesses and delivers it to the appropriate banks.
• A floral delivery company working with multiple local florists to deliver their flowers to customers.

Get Involved

What VRP problem type are you working on?  Join this discussion to describe a problem you are modeling with the VRP solver.