The default value is VERouteMode.Driving.

If the RouteMode property is set to VERouteMode.Driving, the returned route will contain driving directions in the itinerary.

If the RouteMode property is set to VERouteMode.Walking, the returned route will contain walking directions in the itinerary unless the VERouteOptions.UseMWS Property is set to true or the VERouteOptions.UseTraffic Property is set to true, in which case an empty VERoute object is returned. An empty VERoute object has no itinerary and the VERoute.Distance Property and VERoute.Time Property are 0.

If the RouteMode property is set to VERouteMode.Walking and the VERouteOptions.RouteOptimize Property is set to VERouteOptimize.MinimizeTime, then an empty VERoute object is returned.

Reference

Concepts