public DirectionsApiRequest alternatives(boolean alternateRoutes) {
    if (alternateRoutes) {
      return param("alternatives", "true");
    } else {
      return param("alternatives", "false");
    }
  }
If set to true, specifies that the Directions service may provide more than one route
alternative in the response. Note that providing route alternatives may increase the response
time from the server.

@param alternateRoutes whether to return alternate routes.
@return Returns this {@code DirectionsApiRequest} for call chaining.
src/main/java/com/google/maps/DirectionsApiRequest.java