Opinion,

This case is before us in our original jurisdiction. It is a suit against the Commonwealth, in trespass, alleging negligence in failing to properly warn drivers of a dangerous curve and failure to provide an adequate guardrail and shoulder area.

*40The Commonwealth has filed preliminary objections based on sovereign immunity. The preliminary objections must be sustained. See Biello v. Pennsylvania Liquor Control Board, 454 Pa. 179, 301 A.2d 849 (1973) ; Brown v. Commonwealth, 453 Pa. 566, 305 A.2d 868 (1973).