SpeedReadingInterval

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 (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 (Speed)

Traffic speed in this interval.