I worked with the people trying to save this bridge, lead by the Russell County Historic Society.
Initially, VDOT was going to demolish this bridge after the new bridge was opened to traffic. They claimed it was not National Register Eligible and they claimed it was a common bridge type. They also suggested that if for some reason it got flooded out, the historic bridge could crash into and damage the new bridge (unlikely as that might be).
Virginia actually has a low truss bridge population. Using NBI data I composed some statistics about how many truss bridges are in Virginia and also how it compared to other states. I shared this information on HistoricBridges.org and with VDOT.
VDOT responded positively to interaction from everyone's efforts. VDOT agreed to halt plans to demolish the bridge until November 2010, to give the county time to apply for a Transportation Enhancement Grant to preserve the bridge. VDOT actually did a stop work order to prevent the contractors from demolishing the bridge. The timing of all this was right down to the wire!
Not sure what the latest status of the grant is. So, the bridge is not yet "safe" however, until we confirm the grant has been awarded.
I have additional information, history, and photos for this bridge: http://www.historicbridges.org/virginia/blackford/
VDOT has a so-so commitment to preservation. I do not know of a lot of preservation work there, and they do give the appearance of being against historic bridges at the outset, but as this bridge shows, they are at least willing to work with preservationists if enough fuss is made. So they are not as bad as some states (we all know which ones those are).
Interestingly, the bridge is barricaded with no trespassing signs. Could this be somehow indicative of its future? I am not familiar with Virginia's record on historic bridge preservation.