The Vandehei Interchange is open. Full access for motorists will be allowed through the Memorial Day Weekend Wyoming Department of Transportation spokesman Ross Doman says the interchange bridge, two roundabouts, and ramps took 46 days to complete and only one short detour remains on the schedule.   Early morning on Tuesday, May 31, the east side approach to the bridge structure will close for up to 10 days for final work.   Doman says the  interchange will open in full and permanently to travelers by June 10 although slope shaping, seeding, and other clean up will continue. Workers will be in the area until late August. Doman says the improved Vandehei Interchange widens and replaces the bridge deck over I-25. Roundabouts on both ends enhance continuous traffic flow. They allow motorists to take advantage of natural gaps between vehicles and merge rather than make a complete stop. The design accommodates large trucks and trailers.   Bicyclists and pedestrians will enjoy the added safety and convenience of separated sidewalks across the bridge.   The aesthetic improvements include decorative treatments and landscaping that compliments those of other new projects in the area including the Norris Viaduct, High Plains Road Interchange and the improvements on West Lincolnway. The project cost was $6.1 million and Cheyenne’s Reiman Corp. is the primary contractor.   A grand opening event for the improved Vandehei Interchange will occur at a later date.