OPINION BY
President Judge PELLEGRINI.1Kevin Allen (Plaintiff) appeals from an order of the Court of Common Pleas of Wayne County (trial court) sustaining the preliminary objections in the nature of a demurrer of Wayne County, acting in and through the Wayne County Correctional Facility and the Wayne County Commissioners, Brian W. Smith, Anthony V. Herzog and Wendell R. Kay (collectively, County), and dismissing Plaintiffs personal injury complaint on the basis that a county prison inmate is not an employee for purposes of the governmental immunity provisions in Sections 8541-8564 of the Judicial Code, 42 Pa.C.S. §§ 8541-8564, commonly referred to as the Political Subdivision Tort Claims Act (Act). For the reasons that follow, we reverse the trial court’s order and remand for further proceedings consistent with this Opinion.
In September 2009, Plaintiff, while an inmate at the County’s correctional facility, sustained serious injuries when another inmate, Jason Hicks (Hicks), backed into him with a lawn tractor, causing Plaintiffs right leg to become pinned underneath the tractor while they were performing yard work at a correctional facility in Monroe County.
*1037Plaintiff filed a personal injury complaint in the trial court averring that Hicks was an employee or agent of the County within the meaning of 42 Pa.C.S. § 8501; that negligence on the part of the County, through its employee, caused his injuries; and that the circumstances surrounding the accident fell within the vehicle liability exception to governmental immunity, 42 Pa.C.S. § 8542(b)(l). Plaintiff further alleged that the lawn tractor’s reverse warning mechanism was broken or disabled at the time of the accident, and the County’s negligent maintenance of the lawn tractor also fell within the vehicle liability exception. The County filed preliminary objections in the nature of a demurrer.2
Ultimately, the trial court sustained the County’s preliminary objections on the basis that a county prison inmate is not a local agency employee for purposes of liability under the exceptions to governmental immunity in 42 Pa.C.S. § 8542. Without addressing Plaintiff’s claim as to the County’s alleged improper maintenance of the lawn tractor’s reverse warning mechanism, the trial court dismissed Plaintiffs complaint with prejudice. This appeal by Plaintiff followed.3
I.
On appeal, Plaintiff first argues that the trial court erred in holding that an inmate performing yard maintenance at a neighboring county correctional facility is not a county employee for purposes of governmental liability under 42 Pa.C.S. § 8542. Plaintiff contends that inmate Hicks fell within the definition of employee at the time of the accident because he was acting on behalf of the County when he was operating the lawn tractor while doing yard work at the County’s jail.
To impose liability on the County, the Plaintiff must show that the negligent action was caused by the negligence of the local agency or one of its employees and also falls within one of the exceptions to immunity. Section 8542(a), 42 Pa.C.S. § 8542(a), provides, in relevant part:
(a) Liability imposed. — A local agency[4] shall be liable for damages on account of an injury to a person or property within the limits set forth in this subchapter if both of the following conditions are satisfied and the injury occurs as a result of one of the acts set forth in subsection (b):
*1038(1) The damages would be recoverable under common law or a statute creating a cause of action if the injury were caused by a person not having available a defense under section 8541 (relating to governmental immunity generally) or section 8546 (relating to defense of official immunity);[5] and
(2) The injury was caused by the negligent acts of the local agency or an employee thereof acting within the scope of his office or duties with respect to one of the categories listed in subsection (b). As used in this paragraph, ‘negligent acts’ shall not include acts or conduct which constitutes a crime, actual fraud, actual malice or willful misconduct.
(Emphasis added).
The exception to immunity that is applicable to this case is contained in Section 8542(b)(1), which provides, in relevant part:
(b) Acts which may impose liability.— The following acts by a local agency or any of its employees may result in the imposition of liability on a local agency:
(1) Vehicle liability. — The operation of any motor vehicle in the possession or control of the local agency.... As used in this paragraph, ‘motor vehicle’ means any vehicle which is self-propelled and any attachment thereto, including vehicles operated by rail, through water or in the air.
42 Pa.C.S. § 8542(b)(l) (emphasis added).6
The dispute here is whether Hicks was an employee within the meaning of Section 8501 of the Judicial Code, 42 Pa.C.S. § 8501, which defines an “employee” for purposes of the Act as:
Any person who is acting or who has acted on behalf of a government unit whether on a permanent or temporary basis, whether compensated or not and whether within or without the territorial boundaries of the government unit, in-*1039eluding any volunteer fireman and any elected or appointed officer, member of a governing body or other person designated to act for the government unit. Independent contractors under contract to the government unit and their employees and agents and persons performing tasks over which the government unit has no legal right of control are not employees of the government unit.
(Emphasis added).
In finding that Hicks was not an employee under this provision, the trial court relied on a number of cases where this Court has previously held that Pennsylvania inmates are not employees in the context of other statutes. For example, in Heffran v. Department of Labor and Industry, 863 A.2d 1260, 1263 (Pa.Cmwlth.2004), aff'd, 584 Pa. 540, 886 A.2d 222 (2005), in which this Court determined the nature of an inmate’s status for purposes of his rights under the Worker and Community Right-to-Know Act,7 we stated:
It has long been settled that an inmate at a correctional facility is not an employee of the correctional facility because there is no employer/employee relationship as an inmate’s labor belongs to the prison, and the remuneration paid to the inmate is a gratuitous payment authorized by the state as a rehabilitative tool rather than wages. Mays v. Fulcomer, [552 A.2d 750 (Pa.Cmwlth.1989) ].
In Heffran, we relied on Mays, wherein we held that the remuneration received by state prison inmates for services performed at the prison does not constitute “wages” earned by an employee under 42 Pa.C.S. § 8127 (relating to personal earnings exempt from attachment, execution or other process),8 the Minimum Wage Act of 1968,9 or the Unemployment Compensation Law.10 In Mays, we stressed that there is no employer/employee relationship with inmates because their labor belongs to the prison. Mays, 552 A.2d at 753.
Heffran also cited Salah v. Pennsylvania Labor Relations Board, 38 Pa.Cmwlth. 397, 394 A.2d 1053 (1978), in which we held that prison inmates were not public employees under the Public Employe Relations Act11 (PERA) because the purpose of an inmate’s imprisonment is penal and the services an inmate performs are intended to train and rehabilitate, not to provide a source of income as a means of earning a livelihood.12
While the principles stated in those cases may well be true in interpreting *1040other statutes, they are not in accord with the definition contained in 42 Pa.C.S. § 8501, which provides that “any person who is acting ... on behalf of a government unit” is an employee within the meaning of the Act. The purpose of this provision is imposing on local agencies liability for negligent conduct by those acting on their behalf within one of the exceptions to immunity and correspondingly shielding from liability where one of the exceptions does not apply. Moreover, under this provision, the status of the person, the reason the person is engaged in the activity, the purpose for which he or she is engaged in the activity or the lack of a formal employment relationship is irrelevant in determining whether the person is an employee for purposes of tort immunity.13 All that is required is that the person be acting on behalf of the local agency.
In this case, there is no dispute that Hicks is a person or that he was acting on behalf of and at the direction of the County when he injured Plaintiff. Because Hicks falls squarely within the clear and unambiguous language of 42 Pa.C.S. § 8501, he must be considered to be a County employee for purposes of governmental immunity. Accordingly, the trial court erred in sustaining the County’s preliminary objections and dismissing Plaintiffs complaint.
II.
Plaintiff also argues that the trial court erred by failing to address his claim that improper maintenance of the lawn tractor’s reverse warning mechanism qualified as an exception to governmental immunity. In light of the averments in Plaintiffs complaint, we must agree.
In Paragraph 13 of his complaint, Plaintiff averred that the County improperly repaired or maintained the lawn tractor “in that the safety switch designed to alert others when the tractor was in a reverse (or backing up) position was broken and/or disabled.” Compl. at ¶ 13; Reproduced Record (R.R.) at 4. Plaintiff further averred that the negligent maintenance of the tractor fell within the vehicle liability exception to governmental immunity. Id. at ¶ 14; R.R. at 4. Thus, Plaintiff averred that his injuries were due not only to Hicks’ negligent operation of the lawn tractor, but also the County’s negligent maintenance of the lawn tractor, which resulted in the failure of the lawn tractor’s safety mechanism designed to warn others when the lawn tractor is operating in reverse. See id. at ¶¶ 16(a)-(h); R.R. at 5.
In Jones v. Chieffo, 549 Pa. 46, 700 A.2d 417 (1997), our Supreme Court held that where the other elements of the Act are met, a governmental entity is not entitled to immunity simply because a third party’s negligence or criminal conduct is jointly responsible for the harm.
In Powell v. Drumheller, 539 Pa. 484, 653 A.2d 619 (1995), a decedent’s estate brought a wrongful death suit against a drunk driver and the Pennsylvania Department of Transportation (PennDOT). The plaintiff alleged in part that Penn-*1041DOT’S negligent design of the road was a substantial factor in causing the fatal accident. The Supreme Court determined that the rule of joint liability for concurrent causes in cases under the Act applied equally to cases involving sovereign immunity. The Court further reasoned that the question of concurrent causation is normally one for the jury. Powell, 539 Pa. at 492, 653 A.2d at 623.
Further, the Powell Court rejected PennDOT’s argument that the drunk driver’s criminal negligence constituted a superseding intervening cause relieving PennDOT of any liability. In so doing, the Court reasoned:
we do not agree that any violation of a criminal statute constitutes a superseding cause. Instead, the proper focus is not on the criminal nature of the negligent act, but instead on whether the act was so extraordinary as not to be reasonably foreseeable. This was our approach in Crowell. There, the City of Philadelphia similarly argued that the defendant driver’s conviction for driving under the influence was a superseding cause that insulated the City from all liability. We rejected this argument and, instead, found that the driver’s actions in following the misplaced sign were entirely ‘foreseeable.’ Therefore, we cannot conclude that [the drunk driver’s] conviction for driving under the influence was a superseding cause.
A determination of whether an act is so extraordinary as to constitute a superseding cause is normally one to be made by the jury. It is for the jury in the instant case to determine whether [the drunk driver’s] actions in attempting to pass a car while under the influence of alcohol thus crossing into [the decedent’s] lane were so extraordinary as to be unforeseeable to PENNDOT when designing the highway. Accordingly, we cannot say with certainty that no recovery against PENNDOT is possible.
Id. at 495-96, 653 A.2d at 624-25 (citations omitted) (emphasis added).
In light of our Supreme Court’s decisions in Jones and Powell, the County may be found liable for a percentage of Plaintiffs damages based on its alleged negligent maintenance of the lawn tractor as a concurrent cause of his injuries. Therefore, this case should go beyond the pleadings stage to determine whether there is support for Plaintiffs allegation that the County negligently failed to maintain the lawn tractor’s reverse or back-up warning signal and that the County’s negligence was a substantial factor in causing Plaintiffs injuries. Jones.
Furthermore, a potential jury question may also exist as to whether Hicks’ actions in negligently backing up the lawn tractor without checking behind him were so extraordinary as to be unforeseeable to the County. Powell. If a jury finds Hicks’ actions to be foreseeable by the County, they would not constitute a superseding cause relieving the County from liability for its concurrent negligence. Id.
Accordingly, we reverse the trial court’s order and remand for further proceedings to determine whether the County is liable for Plaintiffs injuries caused by the actions of inmate Hicks under the vehicle exception to governmental immunity and whether the County’s alleged negligent maintenance of the lawn tractor’s reverse warning signal was a concurrent cause of Plaintiffs injuries.
Judge McGINLEY dissents.ORDER
AND NOW, this 13th day of September, 2013, the order of the Court of Common Pleas of Wayne County, dated June 28, *10422012, at No. 526-2011-CIVIL, is reversed and the matter is remanded for further proceedings to determine whether the County is liable for Plaintiffs injuries caused by the actions of inmate Jason Hicks under the vehicle exception to governmental immunity and whether the County’s alleged negligent maintenance of the lawn tractor’s reverse warning signal was a concurrent cause of Plaintiffs injuries.
Jurisdiction relinquished.
. This opinion was reassigned to the authoring judge on June 18, 2013.
. Under the Pennsylvania Rules of Civil Procedure, immunity from suit is an affirmative defense properly raised as new matter in a responsive pleading. Smolsky v. Pennsylvania General Assembly, 34 A.3d 316, 321 n. 7 (Pa.Cmwlth.2011). Nonetheless, we recognize that courts permit a limited exception to this rule and allow parties to raise an immunity defense as a preliminary objection. Id. The immunity defense, however, must be clearly applicable on the face of the complaint. Id. Thus, where the plaintiff does not object to the improper procedure, courts may rule on the affirmative defense of immunity when raised in a preliminary objection. Id. Here, Plaintiff raised no objection to the County raising governmental immunity as a preliminary objection.
. Our review of a trial court’s order sustaining preliminary objections in the nature of a demurrer is limited to a determination of whether the trial court abused its discretion or committed an error of law. Bell v. Twp. of Spring Brook, 30 A.3d 554, 557 n. 7 (Pa.Cmwlth.2011). A demurrer admits all-well pled relevant and material facts, and can only be sustained where the right to relief is clear and free from doubt. Id. To that end, conclusions or averments of law shall not be considered admitted as true by a demurrer. Id.
. Section 8501 of the Judicial Code defines "local agency” as "[a] government unit other than the Commonwealth government.” 42 Pa.C.S. § 8501. A county is a local agency to which governmental immunity applies rather than a Commonwealth party protected by sovereign immunity. Simko v. County of Allegheny, 869 A.2d 571, 573 (Pa.Cmwlth.2005).
. The dissent posits that if Hicks is an employee of the County, it must follow that Plaintiff is also an employee of the County. Because employees have no common law cause of action against employers and only have a remedy under the Workers' Compensation Act, Act of June 2, 1915, P.L. 736, as amended, 77 P.S. §§ 1-1041.4, 2501-2708, the dissent contends that Section 8542(a)(1) is not met here. The position is based on the unanalyzed supposition that the definition of who is an "employee” under 42 Pa.C.S. § 8501 for imposing liability for negligence equally applies to the injured Plaintiff.
However, no such argument was ever raised by the County. In fact, in its brief to this Court, the County states: "[Plaintiff's] claim is barred by statutory governmental immunity unless the Court finds that the Wayne County Correctional Facility inmate who was operating the riding lawn mower/tractor was an employee of Wayne County.” (Appellees’ Brief at 4) (emphasis added).
. The County contends in its brief to this Court that a lawn tractor is not a motor vehicle within the meaning of the Act. Because the term "vehicle” is not defined in the Act, the County relies upon Section 102 of the Vehicle Code, 75 Pa.C.S. § 102, which defines "vehicle” as:
Every device in, upon or by which any person or property is or may be transported or drawn upon a highway, except devices used exclusively upon rails or tracks. The term does not include a self-propelled wheel chair or an electrical mobility device operated by and designed for the exclusive use of a person with a mobility-related disability.
This provision directly conflicts with the plain language of the Act because only devices that can be operated on the highway are within the Vehicle Code’s definition, while the Act's definition is much more expansive, including vehicles that operate on land, sea or in the air. Because there is no dispute that the lawn tractor here was self-propelled, it is clearly a "motor vehicle” within the meaning of the Act.
. Act of October 5, 1984, P.L. 734, 35 P.S. §§ 7301-7320 (relating to employers supplying employees with material handling safety data sheets for hazardous substances used in the workplace).
. In 1998, 42 Pa.C.S. § 8127 was amended to allow deductions from inmate remuneration for purposes of collecting restitution.
. Act of January 17, 1968, P.L. 11, as amended, 43 P.S. §§ 333.101-333.115.
. Act of December 5, 1936, Second Ex.Sess., P.L. (1937) 2897, as amended, 43 P.S. §§ 751-914.
. Act of July 23, 1970, P.L. 563, as amended, 43 P.S. §§ 1101.101-1102.2301.
.In its brief, the County also argues that the creation of an employer-employee relationship requires the consent of both parties. Gadd v. Barone, 167 Pa.Super. 477, 75 A.2d 620 (1950); see also, Smalich v. Westfall, 440 Pa. 409, 269 A.2d 476 (1970) (in order for a vehicle driver to be considered as an agent or employee of a vehicle owner, an owner must consent that the driver shall act on his behalf and driver must consent to so act). Here, the County asserts, there is no consent by Hicks to be incarcerated in the County’s correctional facility or to provide labor within the facility.
. For example, a high school football player who accidentally injured a spectator at a school football game was "acting on behalf of the school district” and considered a school district employee within the ambit of 42 Pa.C.S. § 8501 because he was participating in a school-sanctioned activity, represented the school by wearing its uniform, followed his coach’s instructions, and followed school district policies in carrying out the activity. Wilson v. Miladin, 123 Pa.Cmwlth. 405, 553 A.2d 535, 536-37 (1989). See also, Murray v. Zarger, 164 Pa.Cmwlth. 157, 642 A.2d 575, 578 (1994) (”[T]he definition of ‘employee’ in Section 8501 of the Act does not require that an employee be compensated or possess a formal employment contract with the government unit, as long as he is acting in its interests.”)