VRP - returning to depot every 8 hours?

[HenryPeng]

Hi there. Given 24 depots and 500 orders, I'd like to find out how long it would take to visit all of them. The vehicle constraint I would like to have is that they can be on the road for a total of 8 hours (including travel and service time) and must return to the depot before heading out for the next set of visits. So the full route would be a series of 8 hour loops and the total time would be the sum of those loops. I was initially thinking about them having to take an hour break every 8 hours but it doesn't seem like I can specify that the break has to occur at the start location. Or that the range of the vehicle is a total of 8 hours before having to return to the start location to "recharge". Any thoughts on how to accomplish this? The way I'm currently going about this is manually creating multiple routes each with an 8 hour max. Thanks.

[HeatherMoe]

With the 24 depots, does the route need to go back to the exact same depot where it started or are you wanting it to have flexibility to go to any of those depots, it just has to be there by the 8 hour mark?

Your method of making copies of the routes with a MaxTotalTime of 8 hours is what I would suggest for this scenario in most cases. However, I have suggested in a few cases where breaks have to take place at a certain time and location that it can be modeled using an order with a time window and then either use the assignment rule or specialties to connect it to a specific route. Using revenue for the orders that are breaks can also make sure that those are assigned even if out of the way. Something to experiment with if the first option isn't working the way you need it.

Hope that helps,

Heather