• Simon Webb

Route Optimisation Constraints – Time Windows

Or how can I plan optimal driving routes that consider my customers delivery time preferences and requirements?

The purpose of a route optimisation algorithm is to calculate the stopping sequence to visit several jobs that minimises the driving time across a fleet of vehicles. But businesses have many other requirements, minimising the driving time alone may not produce optimal routes for your businesses. To model these requirements, we use Route Optimisation Constraints.


Time Windows are one such constraint. A time window on a job tells the optimisation algorithm that a Job must be visited between certain hours. The algorithm then must plan a route respecting these hours even if there is an alternate stopping sequence that would require less driving time.


Time windows are an important constraint in ensuring a successful delivery and a happy customer. If the shop you are delivering to doesn’t open until 11am a route that gives you a planned eta of 9:30am isn’t very useful.


Time windows in Tarot Routing

In the Tarot Routing platform, we model time windows with Arrive After and Leave By attributes that can be assigned to each Job. A job can have one or both attributes to form its time window

A job with:

· Arrive After = 11:00 cannot be visited before 11am. Any time after is valid

· Leave By = 13:00 cannot be visited after 1pm. Any time before is valid

· Arrive After = 11:00 and Leave By = 13:00 can only be visited between 11am and 1pm


For example,

Here we have optimised 11 jobs without any time window constraints on jobs. The optimisation algorithm has planned 3 hours and 18 minutes of driving time.

Adding leave by constraints to the two northern jobs, the optimisation algorithm is forced to serve them first.

This increases the planned driving time by 5%, from 3 hours and 18 minutes to 3 hours and 29 minutes!


This is just a basic example. If you want to find out more about how you can use Time Windows in Tarot Routing to improve the efficiency of your vehicle fleet, contact us and book a demo today.



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