Are any factual determinations made by the Department of Transportation binding on the appellate court?

"Two rules govern our review. Any factual determinations made by the administrative agency are binding on the appellate court if supported by substantial evidence. [Citation.] Secondly, when the issues involve the proper application of a statute or administrative regulation, the trial court's legal conclusions are not binding on the appellate court." (Osburn v. Department of Transportation (1990) 221 Cal.App.3d 1339, 1344.)