- [JSON representation](https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#SCHEMA_REPRESENTATION)
- [FallbackRoutingMode](https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackRoutingMode)
- [FallbackReason](https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackReason)

Information related to how and why a fallback result was used. If this field is set, then it means the server used a different routing mode from your preferred mode as fallback.

| JSON representation |
|---|
| ``` { "routingMode": enum (`https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackRoutingMode`), "reason": enum (`https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackReason`) } ``` |

| Fields ||
|---|---|
| `routingMode` | ``enum (`https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackRoutingMode`)`` Routing mode used for the response. If fallback was triggered, the mode may be different from routing preference set in the original client request. |
| `reason` | ``enum (`https://developers.google.com/maps/documentation/routes/reference/rest/v2/FallbackInfo#FallbackReason`)`` The reason why fallback response was used instead of the original response. This field is only populated when the fallback mode is triggered and the fallback response is returned. |

## FallbackRoutingMode

Actual routing mode used for returned fallback response.

| Enums ||
|---|---|
| `FALLBACK_ROUTING_MODE_UNSPECIFIED` | Not used. |
| `FALLBACK_TRAFFIC_UNAWARE` | Indicates the `TRAFFIC_UNAWARE` `https://developers.google.com/maps/documentation/routes/reference/rest/v2/RoutingPreference` was used to compute the response. |
| `FALLBACK_TRAFFIC_AWARE` | Indicates the `TRAFFIC_AWARE` `https://developers.google.com/maps/documentation/routes/reference/rest/v2/RoutingPreference` was used to compute the response. |

## FallbackReason

Reasons for using fallback response.

| Enums ||
|---|---|
| `FALLBACK_REASON_UNSPECIFIED` | No fallback reason specified. |
| `SERVER_ERROR` | A server error happened while calculating routes with your preferred routing mode, but we were able to return a result calculated by an alternative mode. |
| `LATENCY_EXCEEDED` | We were not able to finish the calculation with your preferred routing mode on time, but we were able to return a result calculated by an alternative mode. |