The railroad had planned on tearing down the Red Rock Bridge, but instead donated the structure to the states of California and Arizona along with of right of way on either side of the bridge. This was done partially due to the cost of converting the bridge into a highway crossing being less expensive than demolishing the veteran structure. Both states began surveying and planning to rebuild the Red Rock Bridge into a new Colorado River crossing for US 66. Once planning had been completed, the state governments of California and Arizona agreed to split the cost of conversion. The tracks were removed from the bridge and a concrete roadway put in its place. On May 21, 1947, the Red Rock Bridge was reopened to automobile traffic for the first time in 31 years, this time as a dedicated highway crossing. US 66 was immediately re-routed off the Old Trails Bridge onto the Red Rock Bridge. The Old Trails Bridge was originally to be demolished but was instead purchased by the Pacific Gas and Electric Company and now carries part of a natural gas pipeline between California and Texas.