
100 S.W.3d 390 (2002)
James J. HARLESS, Appellant,
v.
Donald P. NILES and Mary Niles, Appellees.
No. 04-02-00389-CV.
Court of Appeals of Texas, San Antonio.
December 24, 2002.
*393 Patricia M. Rosendahl, Lynne M. Jurek, Oppenheim & Associates, Houston, for Appellant.
John C. Chunn, P.C., New Braunfels, for Appellee.
Sitting: CATHERINE STONE, Justice, KAREN ANGELINI, Justice, SANDEE BRYAN MARION, Justice.
*394 Opinion by: SANDEE BRYAN MARION, Justice.
This interlocutory appeal arises from a lawsuit filed by Donald and Mary Niles against James Harless. In their suit, the Niles sought damages for personal injury and property damage they allegedly sustained when Harless's patrol car collided with their vehicle. Harless, a patrol supervisor with the Guadalupe County Sheriff's Department, moved for summary judgment on the grounds that he was entitled to official immunity. The trial court denied his motion, and this appeal ensued. See Tex. Civ. Prac. & Rem.Code Ann. § 51.014(a)(5) (Vernon Supp.2002). We affirm.

BACKGROUND
On the morning of October 1, 1998, an individual reported suspicious activity, possibly involving a burglary, to the Guadalupe County Sheriff's Department. The Sheriff's Department dispatched Officer Gary Vega to the scene. Harless, who was on duty in his office at the Sheriff's Department, and Deputy Jeff Gonzales decided to go to the scene as well. While driving on Interstate Highway 10, Harless followed behind Vega's vehicle until losing sight of him. Harless drove with his patrol car's overhead lights, headlights, and wig-wag lights[1] engaged, but he could not remember whether he had turned on his siren. From I-10, Harless turned south onto FM 775. Once on FM 775, Harless disengaged his overhead lights because he did not want to alert any suspects involved in the possible burglary. At this point, he was still three to four miles from the area of the purported burglary.
FM 775 is a two-lane, farm-to-market road, divided by a broken yellow line. As Harless topped a small hill on FM 775, while traveling at about sixty-five miles per hour, he saw the Niles' vehicle approximately 100 yards ahead, also traveling south at a slower speed. Harless activated his left-hand turn signal, slowed his speed to approximately fifty-five miles per hour, and moved into the northbound lane in an attempt to pass the Niles' vehicle. At this moment, the Niles made a left-hand turn directly into the path of Harless's vehicle. The vehicles collided at the point where the Niles' driveway intersects with FM 775, in a passing zone.
Donald Niles, who was driving, admitted he did not see the patrol car until after the collision, and he did not come to a full stop before attempting to turn into his driveway. He said he did not see anyone behind him before he began his turn, but he could not remember whether he looked into his rearview mirror before turning. Donald admitted the accident occurred in a passing zone. Donald said that, just before the collision, he had slowed to approximately fifteen to twenty-five miles per hour and had activated his left-turn signal before attempting the turn into his driveway.
Donald and Harless both allege they were injured in the accident. The Niles sued Harless for damage to their car, Donald's injuries, and Mary's loss of consortium. Harless moved for summary judgment on the affirmative defense of official immunity and filed a plea to the jurisdiction. The trial court denied the motion for summary judgment, but the record does not reflect a ruling on the plea to the jurisdiction.

IMMUNITY
Harless asserts he is entitled to immunity from suit based upon Texas Tort *395 Claims Act ("the TTCA") sections 101.055 (providing that sovereign immunity is not waived for certain governmental functions), 101.056 (providing that sovereign immunity is not waived when a governmental unit exercises discretionary powers), and 101.062 (providing that sovereign immunity is waived in action against a public agency only if response to 9-1-1 emergency call violates an applicable statute or ordinance). See Tex. Civ. Prac. & Rem.Code Ann. §§ 101.055, 101.056, 101.062 (Vernon 1997). The premise of his argument is that he is entitled to the protections afforded by the TTCA merely by virtue of his position as an employee of a governmental unit of the State of Texas. We disagree. While his position as an employee of the Guadalupe County Sheriff's Department may entitle him to official immunity, his position does not necessarily entitle him to the exceptions to the waiver of sovereign immunity provided under the TTCA.
A plaintiff may sue a state employee in his or her official capacity, individual capacity, or both. Denson v. T.D.C.J.-I.D., 63 S.W.3d 454, 460 (Tex. App.-Tyler 1999, pet. denied). The Niles did not state in their petition whether their claims against Harless were brought against him in his official capacity or his individual capacity. "When a petition fails to specify the capacity in which a person is sued, we will look at the `course of the proceedings' to determine the nature of the liability the plaintiff seeks to impose." Nueces County v. Ferguson, 97 S.W.3d 205, 215 (Tex.App.-Corpus Christi 2002, no pet. h.) (citations and footnote omitted).
The Niles' petition does not name the State of Texas, Guadalupe County, or the Sheriff's Department as defendants. See Vela v. Rocha, 52 S.W.3d 398, 403 (Tex. App.-Corpus Christi 2001, pet. denied) (a suit against a government employee in his official capacity seeks to impose liability on the governmental entity that employs him). The petition states Harless "is an individual resident of Guadalupe County," and no where in the petition is he referred to in his official capacity. The Niles asked for judgment against Harless personally based on his alleged negligence in operating his vehicle, and they did not ask for relief under the TTCA. We conclude that the Niles sued Harless in his individual capacity only. See id. (a suit against a government employee in his individual capacity seeks to impose personal liability on the employee for actions he takes under color of state law). Therefore, Harless was not entitled to rely on the exceptions to the waiver of sovereign immunity contained in the TTCA. Nueces County, 97 S.W.3d at 215; see also Kassen v. Hatley, 887 S.W.2d 4, 12, 14 (government-employed medical personnel not entitled to official immunity, although government medical facilities entitled to sovereign immunity). Accordingly, we consider only whether the trial court erred in denying summary judgment on the basis of Harless's entitlement to official immunity. See Copeland v. Boone, 866 S.W.2d 55, 58 (Tex. App.-San Antonio 1993, writ dism'd w.o.j.) (fact that TTCA does not waive immunity is not a showing that sheriff enjoyed immunity other than that of official immunity).

OFFICIAL IMMUNITY
Official immunity is an affirmative defense that shields governmental employees from personal liability so that they are encouraged to vigorously perform their official duties. Kassen, 887 S.W.2d at 8. A governmental employee is entitled to official immunity for (1) the performance of discretionary duties (2) that are within the *396 scope of the employee's authority, (3) provided that the employee acts in good faith. City of Lancaster v. Chambers, 883 S.W.2d 650, 653 (Tex.1994); see also DeWitt v. Harris County, 904 S.W.2d 650, 652 (Tex. 1995). In deciding whether an employee's summary judgment proof conclusively establishes the official-immunity defense, we must determine whether there are disputed facts material to its elements. In this case, the parties do not dispute that at the time of the accident Harless was acting within the scope of his official duties. But they do dispute whether he was performing a discretionary function in good faith.

DISCRETIONARY FUNCTION
Those actions involving personal deliberation, decision, and judgment are discretionary; whereas, those requiring obedience to orders or the performance of a duty to which the employee has no choice are ministerial. Chambers, 883 S.W.2d at 654. The distinction between these two categories is often one of degree because any official act that is ministerial still requires the employee to use some discretion in its performance. Deaver v. Bridges, 47 S.W.3d 549, 553 (Tex.App.-San Antonio 2000, no pet.). In determining whether an act is discretionary, the issue is whether an employee was performing a discretionary function, not whether he had the discretion to do an allegedly wrongful act while discharging that function or whether the employee's job description included discretionary duties. Chambers, 883 S.W.2d at 653. Also, whether a government employee was negligent is not relevant to this determination. City of Wichita Falls v. Norman, 963 S.W.2d 211, 215 (Tex.App.-Fort Worth 1998, pet. dism'd w.o.j.). If he was performing a discretionary function, then he is protected by official immunity, regardless of whether he was negligent in the exercise of his public duties. Id. Accordingly, our focus here is on whether Harless was performing a discretionary function while operating his patrol car. Chambers, 883 S.W.2d at 653-54; Woods v. Moody, 933 S.W.2d 306, 308 (Tex.App.-Houston [14th Dist.] 1996, no writ).
Harless characterizes his actions as discretionary because he contends he was on duty and responding to an emergency call at the time of the accident. He contends that, while responding to the emergency call, he exercised his discretion in deciding how to utilize his vehicle's emergency equipment and in deciding when and where to pass the Niles' vehicle. The Niles counter that, aside from Harless's and Gonzales's subjective beliefs, there is no evidence the call to the sheriff's office about suspicious activity was an "emergency." The Niles also contend Harless was not responding to the call in "emergency mode" because he was not dispatched to the scene and he was not utilizing his vehicle's emergency equipment.
We are unpersuaded by the Niles' argument that Harless was not performing a discretionary function merely because he was not under orders to proceed to the scene of the alleged burglary. See Chambers, 883 S.W.2d at 654-55 (Supreme Court did not distinguish between officer who saw original moving violation and initiated pursuit, and three other officers who joined the chase in holding that their pursuit was a discretionary act). Nor are we persuaded by the Niles' argument that Harless was not performing a discretionary function merely because he had not activated all of his vehicle's emergency equipment. See id. at 655 (holding that after deciding to pursue suspect, an officer's actions necessarily involve his discretion in determining elements of pursuit such as speed, route, whether to call for backup, or how closely to follow suspect's car).
*397 Instances in which police officers have retained official immunity in the operation of their motor vehicles include when they are involved in a high speed chase, an investigation, or a traffic stop. See Woods, 933 S.W.2d at 308 (and cases cited therein). On the other hand, operating a vehicle in a non-emergency situation does not involve personal deliberation or the exercise of professional expertise, decision, or judgment. Norman, 963 S.W.2d at 216 (mere fact that motorcycle police officer was on patrol at time of accident did not entitle him to official immunity); Woods, 933 S.W.2d at 308 (police officer's act of driving en route to "Harris County business" while on duty held not discretionary). Accordingly, absent special circumstances that suggest the officer was performing a discretionary function, an officer driving a motor vehicle while on official, non-emergency business is performing a ministerial act. Woods, 933 S.W.2d at 308.
Special circumstances will dictate when an "emergency situation" arises requiring an officer to use personal deliberation or exercise professional expertise, decision, or judgment. See id. (holding that decision to pursue a particular suspect fundamentally involves an officer's discretion because officer initially must decide whether to undertake pursuit). Whether "special circumstances" are present and whether the officer's actions involved personal deliberation or the exercise of professional expertise, decision, or judgment is a fact question. See Texas Dept. of Public Safety v. Cordes, 85 S.W.3d 342 (Tex.App.-Austin 2002, no pet.); City of Houston v. Daniels, 66 S.W.3d 420, 425 (Tex.App.-Houston [14th Dist.] 2001, no pet.). In Chambers, the Supreme Court held as follows:
The decision to pursue a particular suspect will fundamentally involve the officer's discretion, because the officer must, in the first instance, elect whether to undertake pursuit. Beyond the initial decision to engage in the chase, a high speed pursuit involves the officer's discretion on a number of levels, including, which route should be followed, at what speed, should back-up be called for, and how closely should the fleeing vehicle be pursued. We hold that these police officers' engaging in a high-speed chase was a discretionary act.
883 S.W.2d at 655.
The evidence here established that Harless was on-duty at the Sheriff's Department when another officer was dispatched to the scene of "suspicious activity," and Harless alone made the decision to drive from the sheriff's office to the scene. There is no dispute that neither Harless nor Gonzales were under orders to proceed to the scene or to provide Vega with assistance. The sheriff's office had no response priority "codes," and no further instructions were provided to Harless or Gonzales as they left the sheriff's office. The record also establishes that Harless had activated some, but not all, of his vehicle's emergency equipment. In his summary judgment affidavit, Harless stated as follows:
As patrol supervisor, it was my procedure to also respond to the 9-1-1 emergency call to lend assistance to the officer responding to such call.... As an experienced police officer, I recognized that the situation being reported was dangerous for the persons involved, the single officer at the scene by himself, and any potential bystanders or neighbors.... I was trying to get to the scene of an emergency as quickly as possible in order to assist those involved and prevent any further criminal acts from occurring.
*398 Gonzales stated in his summary judgment affidavit that,
Deputy Vega was dispatched on this emergency 9-1-1 call and my patrol supervisor, James J. Harless, was listening to the radio conversation regarding this emergency call. Following procedure, [Harless] and I also responded to the 9-1-1 emergency call to lend assistance to [Vega] at the scene of the burglary in progress.
Both Harless and Gonzales said it was imperative that another officer reach the scene as quickly as possible to restore order, subdue any violent offenders, apprehend criminal suspects, and make appropriate arrests.
We conclude the circumstances here are analogous to those in Chambers, and we hold that an officer's decision to respond to a report of suspected on-going criminal activity involves an officer's discretion because the officer initially must decide whether to provide assistance to other officers at the scene of a possible on-going criminal offense. Accordingly, we hold that Harless was performing a discretionary function when he decided to drive to the scene of a possible burglary to lend assistance to another officer.

GOOD FAITH
In determining whether an officer acted in good faith, we apply an objective legal reasonableness test, disregarding the officer's subjective state of mind. See Wadewitz v. Montgomery, 951 S.W.2d 464, 466 (Tex.1997); Chambers, 883 S.W.2d at 656. Simple subjective pronouncements of good faith by an officer, or by experts supporting the officer's assertions, are insufficient as a matter of law to meet the summary judgment movant's burden of showing good faith. Wadewitz, 951 S.W.2d at 467. The test for good faith, in cases such as this, depends on how a reasonably prudent officer could have assessed both the need to which an officer responds and the risks of the officer's course of action, based on the officer's perception of the facts at the time of the event. Id. Therefore, it is incumbent on an officer asserting official immunity not only to explain the urgency of the circumstances requiring police intervention but also to address the degree, likelihood, and obviousness of the risks created by the officer's actions. Id.
The "need" aspect of the test for good faith refers to the urgency of the circumstances requiring police intervention. Id. Need is determined by factors such as the seriousness of the crime to which the officer responds, whether the officer's immediate presence is necessary to prevent injury or loss of life or to apprehend a suspect, and what alternative courses of action, if any, are available to achieve a comparable result. Id. The "risk" aspect of good faith refers to the countervailing public safety concerns: the nature and severity of harm that the officer's actions could cause, the likelihood that any harm would occur, and whether any risk of harm would be clear to a reasonably prudent officer. Id.
Good faith may be established by the testimony of the defendant-officers, if the testimony is clear, positive, direct, otherwise credible, free from contradiction, and readily controvertible. Smith v. Davis, 999 S.W.2d 409, 415 (Tex.App.-Dallas 1999, no pet.); City of Coppell v. Waltman, 997 S.W.2d 633, 638 (Tex.App.-Dallas 1998, pet. denied). Good faith can be established as a matter of law when the official's factual recitation is otherwise supported by the evidence. Medina County Comm'rs Ct. v. The Integrity Group, Inc., 944 S.W.2d 6, 10 (Tex.App.-San Antonio 1996, no writ); see also Murillo v. Garza, 881 S.W.2d 199, 202 (Tex.App.-San Antonio *399 1994, no writ) (good faith not established by conclusory statements unsupported by evidence). In addition, good faith can be established as a matter of law, despite an affidavit's failure to use the objective words suggested by Chambers, if reasonable minds could not differ from the conclusion drawn from the underlying facts. The Integrity Group, Inc., 944 S.W.2d at 10.
If the officer presents sufficient proof to meet his initial summary judgment burden on the issue of good faith, the non-movant must then controvert his proof with a showing elevated from that usually required of non-movants in summary judgment proceedings. Chambers, 883 S.W.2d at 657. The plaintiff must do more than show that a reasonably prudent officer could have acted differently; the plaintiff must show that no reasonable person in the defendant's position could have thought the facts were such that they justified defendant's acts. Id. Good faith is not defeated simply by a showing that the officer was negligent. The test of good faith does not inquire into "what a reasonable person would have done," but into "what a reasonable officer could have believed." Wadewitz, 951 S.W.2d at 467 n. 1.
To establish good faith, Harless relied upon his own testimony and that of Officer Gonzales. Harless's and Gonzales's affidavits provide similar narrative accounts of the events leading up to the accident. As to the "need" prong of the Chambers test, both officers said they recognized "that the situation being reported was dangerous for the persons involved, the single officer at the scene by himself, and any potential bystanders or neighbors." Both stated a need to reach the scene quickly to restore order, subdue any violent offenders, apprehend criminal suspects, and make appropriate arrests.
As for the "risk" prong, Harless's affidavit recites the following:
I did not perceive any significant risk or anticipate any harm to the public in slightly exceeding the speed limit while on FM 775 due to the good visibility of the roadway; the fact that Officer Vega had just traveled the same route in front of me; the fact that I had my [sic] both my headlights and wig-wag lights on at the time; the fact that I had not come across any other vehicles while traveling at this speed; the fact that I slowed my vehicle to within the speed limit prior to beginning to pass the Niles' vehicle; and the minimal traffic on FM 775 at the time.
Harless admitted he was traveling over the posted speed limit of fifty-five miles per hour when he first saw the Niles' vehicle 100 yards ahead of him, as Harless topped a small hill. Gonzales stated he thought Harless was operating the vehicle "reasonably and prudently at all times," and that Harless complied with "any and all applicable procedures in his response to the emergency 9-1-1 call." Gonzales did not perceive any significant risk or anticipate any harm to the public from Harless's decision to turn off his overhead lights, to not utilize his siren, or to exceed the speed limit.
Although Harless's summary judgment evidence stated his perception of the "emergency" nature of the 9-1-1 call, no summary judgment evidence supports his or Gonzales's subjective beliefs about the alleged seriousness of the crime to which they were responding, or whether their immediate presence was necessary to prevent injury or loss of life or to apprehend a suspect. Likewise, although Harless's summary judgment evidence addressed his decision to deactivate his overhead lights once he turned onto FM 775, it did not evaluate the risks associated with passing *400 another vehicle on the left-hand side of the road without the use of his overhead lights or siren, and without some indication that the other driver saw his attempt to turn. Nor does Harless's summary judgment evidence address what alternative courses of action, if any, were available to achieve a comparable result. We conclude that Harless did not conclusively establish he acted in good faith, and the trial court did not err in denying his motion for summary judgment.[2] Accordingly, we affirm the trial court's judgment.
NOTES
[1]  Wig-wag lights are a system attached to the vehicle's headlights that cause the headlights to flash.
[2]  To rebut good faith, the Niles relied, in part, on the affidavit of their expert, Douglas Rivers. In issue five on appeal, Harless asserts that Rivers's affidavit provides no evidence that Harless did not act in good faith. We disagree with Harless's contention that Rivers is unqualified to render an opinion on good faith. Rivers, who has over twenty-four years' experience as a police officer, served for sixteen years as Assistant Chief of Police in Hondo, Texas; eleven years as a police supervisor; was a police patrolman; and is now employed by the Bexar County Hospital District Police Department. He has over 2300 hours of training with the Texas Commission on Law Enforcement Officers Standards. Rivers has sufficient expertise to provide opinion testimony on whether Harless acted in good faith. We also disagree with Harless's contention that Rivers is not an expert on accident reconstruction and his opinion was not based on any tests or scientific evaluations. Rivers's opinion was directed at the propriety of Harless's actions in proceeding to the scene of a purported burglary, the manner in which he used or did not use his vehicle's emergency equipment, and whether Harless's actions constituted good faith. However, we do agree with Harless's contention that Rivers's opinion does not show that "no reasonable person in the defendant's position could have thought the facts were such that they justified defendant's acts." Rivers based his opinion on the Niles' petition, the Texas Department of Public Safety's accident report, records from the Guadalupe County Sheriff's Department, the depositions of Donald Niles, Harless, and Gonzales, and the affidavits of Harless and Gonzales. Rivers addressed the facts leading up to the collision, and he concluded that Harless did not operate his patrol vehicle as a reasonable and prudent patrol officer would have under the circumstances. Expert testimony on good faith "must address what a reasonable officer could have believed under the circumstances... and must be substantiated with reference to each aspect of the Chambers balancing test." Wadewitz, 951 S.W.2d at 466-67 (emphasis in original, citation omitted). Because Rivers did not satisfy this test, his opinion testimony did not raise a fact issue on whether Harless acted in good faith. However, because Harless's summary judgment evidence did not conclusively establish good faith, we need not consider whether the Niles met their burden of rebutting good faith.
