What is the obligation of the wrongdoer of a motor vehicle accident to compensate the wrong party for damages which he could have avoided by reasonable effort or expenditures?

The nature of this obligation was explained in considerably more detail in Green v. Smith (1968) 261 Cal.App.2d 392, 396-397, 67 Cal.Rptr. 796: "A plaintiff cannot be compensated for damages which he could have avoided by reasonable effort or expenditures. [Citations.] The frequent statement of the principle in the terms of a 'duty' imposed on the injured party has been criticized on the theory that a breach of the 'duty' does not give rise to a correlative right of action. [Citations.] It is perhaps more accurate to say that the wrongdoer is not required to compensate the injured party for damages which are avoidable by reasonable effort on the latter's part. [Citations.] ... [p] The doctrine does not require the injured party to take measures which are unreasonable or impractical or which would involve expenditures disproportionate to the loss sought to be avoided or which may be beyond his financial means. [Citations.] ... The fact that reasonable measures other than the one taken would have avoided damage is not, in and of itself, proof of the fact that the one taken, though unsuccessful, was unreasonable. [Citations.] ... The standard by which the reasonableness of the injured party's efforts is to be measured is not as high as the standard required in other areas of law. [Citations.] It is sufficient if he acts reasonably and with due diligence, in good faith. [Citations.]" (See also 2 Assem. J. (1970 Reg.Sess.) pp. 3040-3044.)