A set of values that specify factors to take into consideration when calculating the route.

| Enums ||
|---|---|
| `ROUTING_PREFERENCE_UNSPECIFIED` | No routing preference specified. Default to `TRAFFIC_UNAWARE`. |
| `TRAFFIC_UNAWARE` | Computes routes without taking live traffic conditions into consideration. Suitable when traffic conditions don't matter or are not applicable. Using this value produces the lowest latency. Note: For `https://developers.google.com/maps/documentation/routes/reference/rest/v2/RouteTravelMode` `DRIVE` and `TWO_WHEELER`, the route and duration chosen are based on road network and average time-independent traffic conditions, not current road conditions. Consequently, routes may include roads that are temporarily closed. Results for a given request may vary over time due to changes in the road network, updated average traffic conditions, and the distributed nature of the service. Results may also vary between nearly-equivalent routes at any time or frequency. |
| `TRAFFIC_AWARE` | Calculates routes taking live traffic conditions into consideration. In contrast to `TRAFFIC_AWARE_OPTIMAL`, some optimizations are applied to significantly reduce latency. |
| `TRAFFIC_AWARE_OPTIMAL` | Calculates the routes taking live traffic conditions into consideration, without applying most performance optimizations. Using this value produces the highest latency. |