In an action to recover damages for injuries sustained in an automobile accident, the defendant Volkswagen of America, Inc. appeals from so much of an order of the Supreme Court, Nassau County (Morrison, J.), dated February 5, 1985, as denied its motion and supplemental motion for summary judgment and for leave to amend its verified bill of particulars.
Ordered that the order is affirmed insofar as appealed from, with costs.
This action was originally commenced by service of a summons with notice in 1975 against Mabel B. Gavigan and Thomas Rosetti after an accident in June 1973 between an automobile operated by Rosetti and a Volkswagen driven by the plaintiff Julia L. Gavigan. The plaintiff was rendered a quadriplegic who was able to communicate only through the use of eye-blink responses and some syllable-length vocalizations. By summons dated March 25, 1976, bearing the same index number as the 1975 summons, and a complaint alleging additional causes of action sounding in products liability, Volkswagen of America, Inc. (hereinafter VWOA) and Courtesy Volkswagen, Inc. were also named as parties defendant. In June 1976, these papers were served on VWOA without judicial permission for the addition of new parties as required by CPLR 1003. In its answer, VWOA, inter alia, asserted the affirmative defense of lack of personal jurisdiction, but VWOA, in its bill of particulars in May 1980, limited this defense to long-arm jurisdiction and did not raise the issue of defect in joinder. It was not until August 1984 that an employee of VWOA’s attorney located the original 1975 summons while reviewing the original court file, prompting the present motion seeking, inter alia, leave to amend VWOA’s bill of particulars to include the defense of defective joinder.
VWOA argues that the plaintiffs failure to seek and obtain leave of the court before adding it as a party defendant is a jurisdictional defect mandating dismissal of the complaint as against it (see, Catanese v Lipschitz, 44 AD2d 579, 580). *824However, any objection to such failure has been waived by VWOA (see, McDaniel v Clarkstown Cent. Dist. No. 1, 83 AD2d 624, 625). There, was no prompt motion to dismiss, and, although the defense of lack of personal jurisdiction was raised in VWOA’s answer, the defense was subsequently limited in its bill of particulars (see, McDaniel v Clarkstown Cent. Dist. No. 1, supra). VWOA’s request to amend its bill of particulars was properly denied.
We agree with Special Term that there are material issues of fact which preclude the granting of summary judgment in VWOA’s favor (see, Andre v Pomeroy, 35 NY2d 361; Cunningham v General Elec. Credit Corp., 96 AD2d 502). It had been raining heavily on the evening of the accident, and there is evidence that the subject area of the road was an especially dangerous and improperly designed curve. Although the plaintiff had previously driven on this road, there is no indication as to the number of times she had done so, the hour of day or the weather conditions involved. A significant question of fact is presented as to whether the plaintiff exercised reasonable care under the circumstances, and thus whether she was contributorily negligent (see, Aranzullo v Seidell, 96 AD2d 1048, 1049).
There is also evidence that, after the accident, the back portion of the driver’s seat was "bent backwards * * * further than it had ever gone before”, leading to the plaintiff’s allegations that the seat was improperly designed, manufactured and installed. The plaintiff was allegedly thrown out of this defective seat by the force of the impact and trust into the rear window of the vehicle. Although she was not wearing a seat belt at the time of the accident, the plaintiffs’ expert averred that, due to the loss of structural integrity of the seat system and a "ramping effect” created by the seat’s collapse, a seat belt would not have prevented her "second collision” injuries. Any questions regarding the effect of nonuse of an available seat belt and mitigation of damages are for the trier of fact (see, Spier v Barker, 35 NY2d 444; DiMauro v Metropolitan Suburban Bus Auth., 105 AD2d 236, 242-243). Mangano, Brown and Lawrence, JJ., concur.