concurring.
I fully agree with the majority’s analysis concerning proximate cause, and our overruling of Rothermel. I write separately for the purpose of noting that I do not read the majority opinion to hold that PennDOT has a duty to erect guardrails wherever the highway does not abut a stretch of flat, barren ground, nor even that such an allegation always creates a jury question as to whether the highway is safe for its intended purpose,1 only that the issue has been waived by Penn-*380DOT in this case. Indeed, I would dissent from any such holding unless and until clear and generally accepted scientific evidence is presented on the efficacy of guardrails under modern highway conditions. What little caselaw there is on the subject was developed in the horse and buggy days, and thus is less than helpful today. For instance, it is not at all clear to me that a barrier sufficient to prevent a tractor-trailer from driving off the road at sixty miles per hour would not do more harm than good in many accidents, and neither judges nor juries should be allowed to speculate about such matters. In addition, we are not dealing with a strict liability standard;2 PennDOT has a duty only to act with reasonable prudence, not to make the highways as safe as they can possibly be no matter what the cost or other practical considerations. At such time as this court is presented with a record which contains appropriate scientific evidence, we will be able to determine whether a duty exists (at least under certain circumstances) as a matter of law or whether each plaintiff must present expert testimony of the necessity for guardrails on a case-by-ease basis. Here, in response to PennDOT’s motion for summary judgment, plaintiff came forward with no such evidence.3 Consequently, had Penn-DOT properly preserved the issue, I would have affirmed the grant of summary judgment.
KELLEY, J., joins in this concurring opinion.
. The legal duty owed by PennDOT is that the highway be in "a reasonably safe condition for travel by persons using the road in the ordinary. ..and usual manner and with reasonable care.” Felli v. Commonwealth, Dept. of Transportation, 666 A.2d 775, 777 (Pa.Cmwlth.1995).
. Sovereign immunity has been waived only for negligence. See 42 Pa.C.S. § 8522(a).
. Our Supreme Court has recently held that:
[W]here the non-moving party fails to adduce sufficient evidence to establish the existence of an element essential to his case and on which he hears the burden of proof, then the moving parly is entitled to judgment as a matter of law.
Ertel v. Patriot-News Co., 544 Pa. 93, 101, 674 A.2d 1038, 1042 (1996), cert. denied, — U.S. —, 117 S.Ct. 512, 136 L.Ed.2d 401 (1996) [adopting Celotex Corp. v. Catrett, 477 U.S. 317, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986)].