I presume the intent is to get heavy traffic off the dam itself.
Yes, it was originally started as a DHS project so trucks could make the trip from Vegas to Kingman without having to make the Laughlin route. They stopped all traffic after 911 until they had DHS checkpoints constructed to “randomely” check cars wanting to make the trip not only across the dam but also just to visit it.
Currently all truck traffic must take the route to Laughlin from Boulder City. The new bridge will also take all of the regular traffic off the dam leaving it for only tourist and maintenance traffic.