What is the test for determining whether a public body has a duty to exercise care in the context of a motor vehicle accident?

"[I]n considering the existence of 'duty' in a given case several factors require consideration including 'the foreseeability of harm to the plaintiff, the degree of certainty that the plaintiff suffered injury, the closeness of the connection between the defendant's conduct and the injury suffered, the moral blame attached to the defendant's conduct, the policy of preventing future harm, the extent of the burden to the defendant and consequences to the community of imposing a duty to exercise care with resulting liability for breach, and the availability, costs, and prevalence of insurance for the risk involved. [Citations.]' [Citations.] When public agencies are involved, additional elements include 'the extent of [the agency's] powers, the role imposed upon it by law and the limitations imposed upon it by budget; ...' [Citations.]" (Thompson v. County of Alameda, supra, 27 Cal.3d 750, 165 Cal.Rptr. 370.)