AI-generated Key Takeaways
-
Time windows control the timing of pickups and deliveries within route optimization.
-
Hard time windows are strict requirements that, if unmet, result in skipped shipments.
-
Soft time windows offer flexibility, allowing deliveries outside preferred times for a penalty cost.
-
Combining hard and soft time windows enables nuanced control over delivery schedules.
-
The Google Maps Route Optimization API provides metrics for analyzing the impact of time window constraints on cost and efficiency.
This example shows how to use timeWindows to set pickup and delivery
times for shipments.
For a complete conceptual overview and to learn more ways to use timeWindows,
see the Time windows key
concept
document.
Scenario 1: Delivering within time windows
The following example demonstrates a scenario where a single vehicle must
deliver three shipments within their specified timeWindows.
Example request
This request includes three shipments, each with a different delivery
TimeWindow:
shipments[0]delivery window: 18:00 - 19:00shipments[1]delivery window: 18:00 - 18:30shipments[2]delivery window: 17:30 - 18:00
See an example request with time windows
{ "populatePolylines": false, "populateTransitionPolylines": false, "model": { "globalStartTime": "2023-01-13T16:00:00Z", "globalEndTime": "2023-01-14T16:00:00Z", "shipments": [ { "deliveries": [ { "arrivalLocation": { "latitude": 37.789456, "longitude": -122.390192 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T18:00:00Z", "endTime": "2023-01-13T19:00:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 100.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.789116, "longitude": -122.395080 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T18:00:00Z", "endTime": "2023-01-13T18:30:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 20.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.795242, "longitude": -122.399347 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T17:30:00Z", "endTime": "2023-01-13T18:00:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 50.0 } ], "vehicles": [ { "endLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "startLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "costPerHour": 40.0, "costPerKilometer": 10.0 } ] } }
Example response
The response shows that the optimizer schedules each of the visits to
respect the time windows, delivering shipments with earlier windows first.
See a response to the example request with time windows
{ "routes": [ { "vehicleStartTime": "2023-01-13T17:35:50Z", "vehicleEndTime": "2023-01-13T18:17:24Z", "visits": [ { "isPickup": true, "startTime": "2023-01-13T17:35:50Z", "detour": "0s" }, { "shipmentIndex": 1, "isPickup": true, "startTime": "2023-01-13T17:38:20Z", "detour": "150s" }, { "shipmentIndex": 2, "isPickup": true, "startTime": "2023-01-13T17:40:50Z", "detour": "300s" }, { "shipmentIndex": 2, "startTime": "2023-01-13T17:50:09Z", "detour": "0s" }, { "shipmentIndex": 1, "startTime": "2023-01-13T18:00:00Z", "detour": "796s" }, { "startTime": "2023-01-13T18:07:35Z", "detour": "1520s" } ], "transitions": [ { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:35:50Z" }, { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:38:20Z" }, { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:40:50Z" }, { "travelDuration": "409s", "travelDistanceMeters": 1371, "waitDuration": "0s", "totalDuration": "409s", "startTime": "2023-01-13T17:43:20Z" }, { "travelDuration": "341s", "travelDistanceMeters": 1312, "waitDuration": "0s", "totalDuration": "341s", "startTime": "2023-01-13T17:54:19Z" }, { "travelDuration": "205s", "travelDistanceMeters": 636, "waitDuration": "0s", "totalDuration": "205s", "startTime": "2023-01-13T18:04:10Z" }, { "travelDuration": "339s", "travelDistanceMeters": 1276, "waitDuration": "0s", "totalDuration": "339s", "startTime": "2023-01-13T18:11:45Z" } ], "metrics": { "performedShipmentCount": 3, "travelDuration": "1294s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "1200s", "totalDuration": "2494s", "travelDistanceMeters": 4595 }, "routeCosts": { "model.vehicles.cost_per_hour": 27.711111111111112, "model.vehicles.cost_per_kilometer": 45.95 }, "routeTotalCost": 73.661111111111111 } ], "metrics": { "aggregatedRouteMetrics": { "performedShipmentCount": 3, "travelDuration": "1294s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "1200s", "totalDuration": "2494s", "travelDistanceMeters": 4595 }, "usedVehicleCount": 1, "earliestVehicleStartTime": "2023-01-13T17:35:50Z", "latestVehicleEndTime": "2023-01-13T18:17:24Z", "totalCost": 73.661111111111111, "costs": { "model.vehicles.cost_per_hour": 27.711111111111112, "model.vehicles.cost_per_kilometer": 45.95 } } }
The delivery startTime for each shipment falls within its requested
window:
shipments[2]is delivered at 17:50 (within its 17:30 - 18:00 window).shipments[1]is delivered at 18:00 (within its 18:00 - 18:30 window).shipments[0]is delivered at 18:07 (within its 18:00 - 19:00 window).
Scenario 2: Skipping a shipment due to time windows
The following example demonstrates a scenario where a shipment's time window is
too far apart from the others, making it more cost-effective for the optimizer
to skip the shipment and pay the penaltyCost.
Example request
This request is the same as the first scenario, except one shipment's delivery window is at a different time, much later in the day.
shipments[1]delivery window is now: 21:00 - 21:30
See an example request with time windows that cannot be satisfied
{ "populatePolylines": false, "populateTransitionPolylines": false, "model": { "globalStartTime": "2023-01-13T16:00:00Z", "globalEndTime": "2023-01-14T16:00:00Z", "shipments": [ { "deliveries": [ { "arrivalLocation": { "latitude": 37.789456, "longitude": -122.390192 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T18:00:00Z", "endTime": "2023-01-13T19:00:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 100.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.789116, "longitude": -122.395080 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T21:00:00Z", "endTime": "2023-01-13T21:30:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 20.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.795242, "longitude": -122.399347 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T17:30:00Z", "endTime": "2023-01-13T18:00:00Z" } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 50.0 } ], "vehicles": [ { "endLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "startLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "costPerHour": 40.0, "costPerKilometer": 10.0 } ] } }
Example response
The response shows that the optimizer skips shipment[1]. This happens because,
to deliver that shipment, the vehicle would have to operate for several extra
hours, and the calculated cost for that time is higher than the shipment's
penaltyCost of 20.0.
See a response to the example request with time windows where a shipment is skipped
{ "routes": [ { "vehicleStartTime": "2023-01-13T17:37:49Z", "vehicleEndTime": "2023-01-13T18:09:49Z", "visits": [ { "isPickup": true, "startTime": "2023-01-13T17:37:49Z", "detour": "0s" }, { "shipmentIndex": 2, "isPickup": true, "startTime": "2023-01-13T17:40:19Z", "detour": "150s" }, { "shipmentIndex": 2, "startTime": "2023-01-13T17:49:38Z", "detour": "0s" }, { "startTime": "2023-01-13T18:00:00Z", "detour": "946s" } ], "transitions": [ { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:37:49Z" }, { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:40:19Z" }, { "travelDuration": "409s", "travelDistanceMeters": 1371, "waitDuration": "0s", "totalDuration": "409s", "startTime": "2023-01-13T17:42:49Z" }, { "travelDuration": "372s", "travelDistanceMeters": 1348, "waitDuration": "0s", "totalDuration": "372s", "startTime": "2023-01-13T17:53:48Z" }, { "travelDuration": "339s", "travelDistanceMeters": 1276, "waitDuration": "0s", "totalDuration": "339s", "startTime": "2023-01-13T18:04:10Z" } ], "metrics": { "performedShipmentCount": 2, "travelDuration": "1120s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "800s", "totalDuration": "1920s", "travelDistanceMeters": 3995 }, "routeCosts": { "model.vehicles.cost_per_kilometer": 39.95, "model.vehicles.cost_per_hour": 21.333333333333332 }, "routeTotalCost": 61.283333333333331 } ], "skippedShipments": [ { "index": 1 } ], "metrics": { "aggregatedRouteMetrics": { "performedShipmentCount": 2, "travelDuration": "1120s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "800s", "totalDuration": "1920s", "travelDistanceMeters": 3995 }, "usedVehicleCount": 1, "earliestVehicleStartTime": "2023-01-13T17:37:49Z", "latestVehicleEndTime": "2023-01-13T18:09:49Z", "totalCost": 81.283333333333331, "costs": { "model.shipments.penalty_cost": 20, "model.vehicles.cost_per_hour": 21.333333333333332, "model.vehicles.cost_per_kilometer": 39.95 } } }
The skippedShipments array in the response shows that the shipment with
index: 1 was not performed. which affects the following cost parameters:
- The
penaltyCostof 20.0 from that shipment is included in themetrics.costs. - The
totalCost(81.28) is the sum of therouteTotalCost(61.28) and thepenalty_cost(20.0).
Scenario 3: Using soft time windows
The following example shows how to use a soft time window, which allows the optimizer to schedule a delivery outside of the specified time range, but at a cost.
For a conceptual overview of this feature, see the soft time windows section in the Time Windows key concepts document.
Example request
This request modifies the previous scenario by changing the hard time window for
shipment[1] to a soft one. This is done by using softStartTime and
providing a costPerHourBeforeSoftStartTime.
shipment[1] now has a softStartTime of 21:00 and a
costPerHourBeforeSoftStartTime of 2.0. This means a penalty is applied
for every hour the delivery is made before 21:00.
See an example request with hard and soft time windows
{ "populatePolylines": false, "populateTransitionPolylines": false, "model": { "globalStartTime": "2023-01-13T16:00:00Z", "globalEndTime": "2023-01-14T16:00:00Z", "shipments": [ { "deliveries": [ { "arrivalLocation": { "latitude": 37.789456, "longitude": -122.390192 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T18:00:00Z", "softEndTime": "2023-01-13T19:00:00Z", "costPerHourAfterSoftEndTime": 2.0 } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 100.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.789116, "longitude": -122.395080 }, "duration": "250s", "timeWindows": [ { "softStartTime": "2023-01-13T21:00:00Z", "endTime": "2023-01-13T21:30:00Z", "costPerHourBeforeSoftStartTime": 2.0 } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 20.0 }, { "deliveries": [ { "arrivalLocation": { "latitude": 37.795242, "longitude": -122.399347 }, "duration": "250s", "timeWindows": [ { "startTime": "2023-01-13T17:30:00Z", "softEndTime": "2023-01-13T18:00:00Z", "costPerHourAfterSoftEndTime": 2.0 } ] } ], "pickups": [ { "arrivalLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "duration": "150s" } ], "penaltyCost": 50.0 } ], "vehicles": [ { "endLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "startLocation": { "latitude": 37.794465, "longitude": -122.394839 }, "costPerHour": 40.0, "costPerKilometer": 10.0 } ] } }
Example response
The response shows that the optimizer now schedules all three shipments. It
schedules the delivery of shipment[1] significantly earlier than its 21:00
softStartTime. This is the most cost-effective solution since the cost
of violating the soft time window is less than the penaltyCost of
skipping the shipment, and it's also lower than the cost of having a vehicle
wait to deliver during the time window.
See a response to the example request with hard and soft time windows
{ "routes": [ { "vehicleStartTime": "2023-01-13T17:48:35Z", "vehicleEndTime": "2023-01-13T18:24:28Z", "visits": [ { "isPickup": true, "startTime": "2023-01-13T17:48:35Z", "detour": "0s" }, { "shipmentIndex": 1, "isPickup": true, "startTime": "2023-01-13T17:51:05Z", "detour": "150s" }, { "shipmentIndex": 2, "isPickup": true, "startTime": "2023-01-13T17:53:35Z", "detour": "300s" }, { "startTime": "2023-01-13T18:00:00Z", "detour": "300s" }, { "shipmentIndex": 1, "startTime": "2023-01-13T18:07:42Z", "detour": "493s" }, { "shipmentIndex": 2, "startTime": "2023-01-13T18:17:27Z", "detour": "873s" } ], "transitions": [ { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:48:35Z" }, { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:51:05Z" }, { "travelDuration": "0s", "waitDuration": "0s", "totalDuration": "0s", "startTime": "2023-01-13T17:53:35Z" }, { "travelDuration": "235s", "travelDistanceMeters": 795, "waitDuration": "0s", "totalDuration": "235s", "startTime": "2023-01-13T17:56:05Z" }, { "travelDuration": "212s", "travelDistanceMeters": 791, "waitDuration": "0s", "totalDuration": "212s", "startTime": "2023-01-13T18:04:10Z" }, { "travelDuration": "335s", "travelDistanceMeters": 1204, "waitDuration": "0s", "totalDuration": "335s", "startTime": "2023-01-13T18:11:52Z" }, { "travelDuration": "171s", "travelDistanceMeters": 665, "waitDuration": "0s", "totalDuration": "171s", "startTime": "2023-01-13T18:21:37Z" } ], "metrics": { "performedShipmentCount": 3, "travelDuration": "953s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "1200s", "totalDuration": "2153s", "travelDistanceMeters": 3455 }, "routeCosts": { "model.shipments.deliveries.time_windows.cost_per_hour_after_soft_end_time": 0.58166666666666667, "model.shipments.deliveries.time_windows.cost_per_hour_before_soft_start_time": 5.7433333333333332, "model.vehicles.cost_per_hour": 23.922222222222221, "model.vehicles.cost_per_kilometer": 34.55 }, "routeTotalCost": 64.797222222222217 } ], "metrics": { "aggregatedRouteMetrics": { "performedShipmentCount": 3, "travelDuration": "953s", "waitDuration": "0s", "delayDuration": "0s", "breakDuration": "0s", "visitDuration": "1200s", "totalDuration": "2153s", "travelDistanceMeters": 3455 }, "usedVehicleCount": 1, "earliestVehicleStartTime": "2023-01-13T17:48:35Z", "latestVehicleEndTime": "2023-01-13T18:24:28Z", "totalCost": 64.797222222222217, "costs": { "model.vehicles.cost_per_kilometer": 34.55, "model.shipments.deliveries.time_windows.cost_per_hour_before_soft_start_time": 5.7433333333333332, "model.shipments.deliveries.time_windows.cost_per_hour_after_soft_end_time": 0.58166666666666667, "model.vehicles.cost_per_hour": 23.922222222222221 } } }
The soft time window results in a better solution, which is reflected in the following improvements:
- All 3 shipments are scheduled without skipping any of them.
- The
totalCostis now 64.79, which is lower than the previous solution's cost of 81.28. - The
routeCostsobject includes a cost of 5.74 for deliveringshipment[1]almost 3 hours before itssoftStartTime. This cost is lower than thepenaltyCostof 20.0, making it the most cost-effective option.