Time Based Constraints

Constraints involving time windows, durations, and scheduling logic.

Wait Time (Slack): While a time constraint, managing slack is also key to route compactness.
Maximum Trip Duration: A hard time limit that affects route shape.

📄️ Finalization Type

The Finalization Type is a post-processing instruction that fine-tunes the exact scheduled time for a stop after the optimal route has already been determined.

📄️ Compound Zones: Setting Entry and Exit Time Penalties

Certain delivery or pickup areas, like large industrial parks, gated communities, or restricted city centers, require additional time simply to enter or exit the area, regardless of the specific stop location within it. These "compound zones" might involve navigating security gates, internal road networks, or specific traffic patterns. This model is supported by SWAT APIs using a compound_zones parameter to add these time penalties.

📄️ Limiting capacity of the warehouse

Warehouses often have limited capacity, requiring restrictions on the number of trucks serviced concurrently. This model is supported by SWAT APIs and a cumulative limitation parameter can be used to enforce this constraint.

📄️ Driver breaks

Both the SWAT Optimization API and Integration API support driver breaks, allowing dynamic allocation to align with operational needs or legal requirements. For example, Route Optimization can incorporate the length of required breaks after specific driving durations into its execution plan while respecting other set constraints. Two main use cases apply, which can be used in a mutually exclusive manner when simulating the addition of driver breaks to optimization:

📄️ Dynamic Service Time

In logistics, the time it takes to service an order at a drop-off location (like a warehouse or distribution center) is often not a fixed number. It can vary based on the size, weight, or type of goods being delivered. Dynamic Service Time is a feature that allows the optimization engine to calculate the service time for an order based on these variable factors, rather than using a single static value.

📄️ Just-In-Time (JIT) Employee Transport: Optimizing Workforce Mobility

Just-in-time (JIT) employee transport focuses on precisely coordinating the movement of employees to align with their work schedules and real-time needs, eliminating unnecessary wait times and maximizing operational efficiency. It's about ensuring the right people are in the right place at the right time, every time.

📄️ Maximum trip duration

In the Vehicle Routing Problem (VRP), a trip refers to the sequence of nodes visited by a single vehicle, starting from the depot and ending back at the depot. A route can consist of one or more trips, especially when dealing with constraints like maximum trip duration or vehicle capacity. The maximum trip duration constraint limits the total time a vehicle can spend on a single trip.

📄️ Vehicle slack

In the context of a Vehicle Routing Problem (VRP), slack (also commonly called waiting time) is the unproductive idle time that a vehicle and driver must spend at a stop.

📄️ Time windows in CPVRPTW problems

The Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) extends the classic VRP by incorporating two key real-world constraints: vehicle capacity and time windows. Time windows, which restrict when a customer can be serviced, are crucial for modeling realistic scenarios and significantly impact solution feasibility and cost.

📄️ Vehicle working hours

Defining the start time and end time for a vehicle is crucial for accurately modeling real-world logistics operations. These parameters define the working shift of a driver or the availability window of a vehicle.

📄️ Multiple Time Windows

In standard VRP problems, a node (pickup or drop-off) typically has a single time window defined by opentimets and closetimets. However, in many real-world scenarios, a location might be accessible during multiple disjoint time intervals. For example, a warehouse might be open for deliveries from 0800 and then again from 1400, closing for a lunch break in between.

Related Route Quality Concepts​