Lake Tahoe, Emerald Bay Railing

The publication "Flexibility in Highway Design," published by the Federal Highway Works Administration (FHWA ) in 1997, summarizes the negotiation between Caltrans and the Tahoe Regional Planning Agency (TRPA):

Although the original barrier design proposed by Caltrans was the generally accepted statewide standard for such applications, it was considered to be unacceptable by the TRPA.  The two-beam guardrail which was finally installed had been crash tested by the FHWA some years earlier but had not, at the time of this project, been adopted by Caltrans as an acceptable guardrail type. Subsequent to the project, the two-beam guardrail design was accepted by Caltrans as a standard design, particularly in areas with similar aesthetic considerations.[i]

The photo on the left below shows the railing that Caltrans installed at Emerald Bay.  The one on the right is a Wyoming Rail (TL-3 version) near Yellowstone Park.