# SpeedReadingInterval

- [JSON representation](https://developers.google.com/maps/documentation/routes_preferred/reference/rest/Shared.Types/SpeedReadingInterval#SCHEMA_REPRESENTATION)

Traffic density indicator on a contiguous segment of a polyline or path. Given a path with points P_0, P_1, ... , P_N (zero-based index), the `SpeedReadingInterval` defines an interval and describes its traffic using the following categories.

| JSON representation |
|---|
| ``` { "startPolylinePointIndex": integer, "endPolylinePointIndex": integer, "speed": enum (`https://developers.google.com/maps/documentation/routes_preferred/reference/rest/Shared.Types/Speed`) } ``` |

| Fields ||
|---|---|
| `startPolylinePointIndex` | `integer` The starting index of this interval in the polyline. In JSON, when the index is 0, the field appears to be unpopulated. |
| `endPolylinePointIndex` | `integer` The ending index of this interval in the polyline. In JSON, when the index is 0, the field appears to be unpopulated. |
| `speed` | ``enum (`https://developers.google.com/maps/documentation/routes_preferred/reference/rest/Shared.Types/Speed`)`` Traffic speed in this interval. |