Specify the traffic model type to use

Traffic models use specific algorithms and factors to predict how traffic conditions impact total travel time for a given route. The Routes API offers different traffic model types to prioritize different factors used in calculating duration in traffic. You can specify the traffic model type you'd like your routes to use when calculating the duration for your routes or route matrix. When you set the traffic model type, the value returned in the durationfield varies depending on the traffic model you choose.

Both the Routes APICompute Routesand Compute Route Matrixmethods support traffic model types.

By default, both methods use theBEST_GUESStraffic model type.

To specify a traffic type

Set your origin and destination.
If your departure time is in the future, include the time using the departure_timeparameter. If you don't specify a departure time, it defaults to now.
Select the traffic model to use with thetrafficModelparameter and one of the following types:
- BEST_GUESS(default) to request that the returnedduration_in_traffic is the best estimate of travel time given what is known about both historical traffic conditions and live traffic. Live traffic becomes more important the closer thedeparture_timeis to now. Using the default type ofBEST_GUESSgives the most useful predictions for the vast majority of use cases.
- PESSIMISTICto request that the returnedduration_in_trafficmodels the time based on the historical traffic conditions on bad traffic days. This type gives an estimated duration that is most likelylongerthan the actual travel time on most days. Occasional days with particularly bad conditions may still exceed this estimate.
- OPTIMISTICto request that the returnedduration_in_trafficmodels the time based on the historical traffic conditions on good traffic days. This type gives an estimated duration that is most likelyshorterthan the actual travel time on most days. Occasional days with particularly good conditions may still be faster than this estimate.
For example:
```
"trafficModel": "OPTIMISTIC"
```
Note:It is possible theBEST_GUESStravel time prediction may be shorter thanOPTIMISTICor longer thanPESSIMISTIC,due to the way BEST_GUESSintegrates live traffic information.

Specify theroutes.durationfield in the field mask.

REST

-H X-Goog-FieldMask: routes.duration

RPC

const (fieldMask = "routes.duration" )

When the Routes API estimates time in traffic, it uses the traffic model type you've requested.

Example: Traffic model request

For example, this request specifies that the duration be estimated using the OPTIMISTICtraffic model type at a specific departure time:

curl -X POST -H 'content-type: application/json' -d ' {
"origin": {
"address": "Kyoto, Japan"
},
"destination": {
"placeId": "ChIJrYtcv-urAWAR3XzWvXv8n_s"
},
"travelMode": "DRIVE",
"routingPreference": "TRAFFIC_AWARE_OPTIMAL",
"trafficModel": "OPTIMISTIC"
}' \
-H 'Content-Type: application/json' \
-H 'X-Goog-Api-Key:YOUR_API_KEY' \
-H 'X-Goog-FieldMask: routes.duration' \
'https://routes.googleapis /directions/v2:computeRoutes'

This request returns the estimated duration using theOPTIMISTICtraffic model type for the trip:

"duration": "1238s"

If you change the traffic model type toPESSIMISTIC,the returned duration is longer:

"duration": "2436s"