¶ 59. {concurring). This case has been argued and analyzed as a case involving an investigatory stop. In this context, the principal question is whether officers Johnny Norred and Phillip Henschel had reasonable suspicion for an investigatory stop while the defendant and another person were sitting in the front seat of an automobile parked behind an apartment building at 4261 North Teutonia Avenue in Milwaukee. While I join in the mandate and opinion of the court, I write this concurrence to help explain my belief that the two officers were on very solid footing when they acted as they did.
*188TOTALITY OF THE CIRCUMSTANCES
¶ 60. The court is obliged to take into account the totality of the circumstances in determining whether the police had sufficient evidence to warrant an investigatory stop. Illinois v. Gates, 462 U.S. 213, 230-33 (1983); State v. Richardson, 156 Wis. 2d 128, 456 N.W.2d 830 (1990). The totality of the circumstances includes the direct observations of the two officers, the collective information in the police agency, and the experience of the officers in evaluating the information available.
¶ 61. The knowledge of the two officers is combined in determining the existence of either reasonable suspicion or probable cause. Moreover, the information possessed by the entire police department is imputed to these officers under long-standing Wisconsin law. In State v. Mabra, 61 Wis. 2d 613, 625-26, 213 N.W.2d 545 (1974), the court, speaking through Chief Justice Hallows, stated:
Mabra contends the arresting officer must personally have in his mind knowledge sufficient to establish probable cause for the arrest. This is an incorrect view of the law. The arresting officer may rely on all the collective information in the police department. . . .The police force is considered as a unit and where there is police-channel communication to the arresting officer and he acts in good faith thereon, the arrest is based on probable cause when such facts exist within the police department. Whiteley v. Warden (1971), 401 U.S. 560, 91 Sup. Ct. 1031, 28 L. Ed. 2d 306.
¶ 62. These principles were repeated in Desjarlais v. State, 73 Wis. 2d 480, 491-92, 243 N.W.2d 453 (1976) (citing State v. Taylor, 60 Wis. 2d 506, 515, *189210 N.W.2d 873 (1973)), and State v. Shears, 68 Wis. 2d 217, 253, 229 N.W.2d 103 (1975). "[W]here an arresting officer is given information through police channels such as roll call, this court's assessment of whether the arrest was supported by probable cause is to be made on the collective knowledge of the police force." State v. Cheers, 102 Wis. 2d 367, 388, 306 N.W.2d 676 (1981) (citing Schaffer v. State, 75 Wis. 2d 673, 676-77, 250 N.W.2d 326 (1977), overruled on other grounds, State v. Walker, 154 Wis. 2d 158, 453 N.W.2d 127 (1990)).
¶ 63. The collective knowledge rule is not a parochial Wisconsin invention. It is prevalent throughout the United States. For instance, the Minnesota Supreme Court said: "The test in Minnesota under the 'collective knowledge' approach, is whether the pooled knowledge of the entire police department is sufficient to establish probable cause." State v. Eling, 355 N.W.2d 286, 290 (Minn. 1984) (citing State v. Conaway, 319 N.W.2d 35, 40 (Minn. 1982)).1
911 CALLER
¶ 64. Against this background, the person who called 911, saying that drugs were being sold from a vehicle parked behind her apartment building at 4261 North Teutonia Avenue, should not be viewed as an anonymous tipster. The police knew the caller's identity or could easily have discovered it because of the information provided by 911.
¶ 65. Today, the 911 emergency telephone number is familiar to most people in Wisconsin. According to a 1997 audit by the Legislative Audit Bureau, "As of *190May 1997, an estimated 94 percent of the State's population was receiving 9-1-1 service from one of 121 answering points being operated in the 57 counties that provide 9-1-1 service." A Best Practices Review: 911 Services, State of Wisconsin Legislative Audit Bureau (July 1997), at 3. The audit indicated that 105 of the 121 answering points operate an "enhanced 9-1-1 system," which automatically identifies and displays the caller's telephone number and location. Id. at 4.
¶ 66. There is a statutory framework for the "statewide emergency services number." See Wis. Stat. § 146.70. Subsection (l)(i) of the statute defines "sophisticated system" as "a basic system with automatic location identification and automatic number identification." A "sophisticated system" and the "enhanced 9-1-1 system" referred to in the audit are essentially the same thing.
¶ 67. An "enhanced" system normally provides authorities with (1) the name of the residence or place of business where the incoming call is made, (2) the address of the residence or place of business where the incoming call is made, and (3) the telephone number of the phone from which the incoming call is made.2
¶ 68. The 1997 audit states that Milwaukee has had an enhanced system since 1989. A Best Practices Review: 911 Services, supra, Appendix III at 2. This is confirmed by news reports from Milwaukee newspapers. "By nearly 8 to 1, voters said in a referendum that they wanted [Milwaukee] County to establish a 911 *191system, which automatically records a caller's telephone number and address at a central dispatch location, even if the caller cannot speak." 911 System Wins Big in County Referendum, MILWAUKEE JOURNAL, November 5,1986, at 3B.
¶ 69. In a later article, Leverett F. Baldwin, then emergency government services director of Milwaukee County, now Milwaukee County Sheriff, is quoted as saying that the 911 system was expected to eliminate most prank calls because the caller's telephone number and address will be recorded and will be easy to track down. Ralph D. Olive, Single Number May Call for Help, Milwaukee Journal, January 18,1988, at 3B.
¶ 70. In fact, the legislature established criminal penalties for any person who intentionally dials the telephone number "911" to report an emergency, "knowing that the fact situation which he or she reports does not exist...." Wis. Stat. § 146.70(10). This penalty provision long predated the 911 call in this case.
¶ 71. Florida has a similar penalty. In United States v. Gibson, 64 F.3d 617, 625 (11th Cir. 1995), the court observed that, "The state of Florida provides a significant deterrent against reporting false information to its law enforcement agencies and officers by making such acts punishable by law. FLA. STAT. ANN. § 365.171(16) (West 1995) (false "911" calls); Id. § 817.49 (false reports of commission of crimes to law enforcement officers). This deterrent increases the odds that an anonymous tip is legitimate." (Emphasis added.)
¶ 72. When the police received the 911 call in this case, they knew at a minimum the address and phone number of the caller, and the call was recorded. The dispatcher never asked for the caller's name, address, *192or telephone number; rather, the dispatcher replied "Um hmm" when the caller disclosed that, "I stay at 4261 North Teutonia." In giving her address, the caller confirmed what the dispatcher already knew.
¶ 73. The dispatcher did ask whether the caller had a description of the van, and the caller replied: "Um, hold on, I can get for you." Then the caller returned and gave a more detailed description of the vehicle. The color of the vehicle, the location of the vehicle, and the fact that more than one person was in the vehicle were either described or alluded to by the caller and later confirmed by the officers. In addition, the caller answered all other questions asked by the dispatcher.
¶ 74. The recorded call and its subsequent transcript show both the caller's basis of information and the caller's reliability. But the fact that the agency either knew the identity of the caller or had the means to discover the caller's identity puts the call in a different light. The caller politely asked for police intervention in alleged criminal activity she was witnessing. In effect, the caller was saying: "Come quickly. As you know, I am at my apartment, and I am watching criminal activity out my back window." Were this information false, the police would have been able to follow up and confront the caller, demand an explanation, and perhaps press criminal charges.
¶ 75. In my view, then, this case does not involve an anonymous tipster or an anonymous caller. The essence of anonymity is being unknown. Anonymity and confidentiality are cousins, not twins. A confidential informant is an informant whose identity is assiduously withheld. An anonymous informant is an informant whose identity is unknown. The identity of the caller in this case was not unknown. It has been *193kept confidential out of respect to a citizen who came forward to report what she saw.
LOCATION OF THE VEHICLE
¶ 76. When the officers arrived at the scene, they were able to see the blue and burgundy vehicle from "quite a distance." The Chevy Blazer was parked in an alley or in a parking lot adjacent to an alley behind a building on Teutonia. The building is located on the west side of Teutonia. An "empty lot-type deal" is located near the building.
¶ 77. Strategically, the subject vehicle was not parked on a street where it could be easily observed. It was parked in or near an alley, behind a building, where it was partially concealed fróm traffic on Teutonia.
¶ 78. In its decision, the court of appeals declared that:
We note, as did the court in Roberson, "that the police were not powerless to act on the non-predictive, anonymous tip they received. The officers could have set up surveillance of the defendant." Indeed, particularly in cases of drug dealing, excellent police work consists, in part, of surveillance leading not only to solid evidence against a suspect, but also to additional arrests of those the police observe engaging in drug transactions with the suspect.
State v. Williams, 214 Wis. 2d 412, 424, 570 N.W.2d 892 (Ct. App. 1997).
¶ 79. This advice presupposes that the situation permitted surveillance. The record does not provide evidence that a marked squad car could have stopped to watch the vehicle without itself being seen. We know *194that this case is different from U.S. v. Roberson, 90 F.3d 75 (3d Cir. 1996), because in Roberson the criminal activity was out on the street, not in an alley. We also know that the officers here circled around the block trying to approach the vehicle without being seen.
¶ 80. The officers first saw the Blazer at "quite a distance." Had the occupants seen the squad car at "quite a distance," they could have started the car and attempted to drive away. Then the officers would have faced a decision whether to stop a moving vehicle. Cf. State v. Harris, 206 Wis. 2d 243, 557 N.W.2d 245 (1996).
ABSENCE OF LICENSE PLATES
¶ 81. Officers Norred and Henschel drove north on Teutonia Avenue past the building and then turned west on Roosevelt Drive. Eventually, they entered the alley at a point where they thought their squad car would be concealed. They drove through the alley, coming up to the front of the Chevy Blazer. There were no license plates on the car.
¶ 82. Like 29 other states and the District of Columbia, Wisconsin requires two license plates on a car.3 For the last 20 years, there have been efforts in the Wisconsin legislature to move from two license plates to one license plate. But, according to the Legislative Fiscal Bureau, "the major objection to the single license plate proposal has been expressed by law enforcement officials. They contend that the front *195license plate has value because it allows identification of oncoming and parked vehicles."4
¶ 83. In this case, there were no plates on the Blazer. Under the circumstances, the primary concern of the police officers would have been identifying the vehicle, not ticketing the driver for a motor vehicle violation. From the point of view of the officers, the suspected drug vehicle had been stripped of the standard means of identifying it. The absence of license plates added to the evidence which permitted the officers reasonably to conclude in light of their training and experience that criminal activity might be afoot. Terry v. Ohio, 392 U.S. 1, 30 (1968).
¶ 84. In State v. Griffin, 183 Wis. 2d 327, 329, 515 N.W.2d 535 (Ct. App. 1994), review denied, 520 N.W.2d 88 (1994), cert. denied, 513 U.S. 950 (1994), the court of appeals held that the absence of license plates, and reasonable inferences that can be drawn from that fact, provide reasonable suspicion sufficient to justify an investigatory stop of a motor vehicle. The absence of license plates in this case, as evidenced by the record, combined with the court of appeals' holding in Griffin, provides further support that the officers had reasonable suspicion to make an investigatory stop.
*196¶ 85. Reasonable suspicion is a smaller quantum of evidence than probable cause because the temporary seizure of a person in an investigatory stop is less than the complete and lasting seizure of a person in an arrest. In my view, the two officers had more than reasonable suspicion to make an investigatory stop. Consequently, I concur in the mandate and opinion of the court.
See also United States v. Green, 962 F.2d 938, 942 (9th Cir. 1992); Charles v. Smith, 894 F.2d 718, 724 (5th Cir. 1990), cert. denied 498 U.S. 957 (1990); United States v. Hoyos, 892 F.2d 1387, 1392 (9th Cir. 1989), cert. denied 498 U.S. 825 (1990).
At present, a cellular phone call will not provide this information, so that when a cellular call is received, the dispatcher must ask the caller for identification if it is not volunteered. A Best Practices Review: 911 Services, State of Wisconsin Legislative Audit Bureau (July 1997), at 7.
See Wis. Stat. §§341.12(1) and 341.15(1). See also The Fast Track to Vehicle Services Facts, A Motor Vehicle Regulations and Procedures Information Guide (1999 ed.), American Association of Motor Vehicle Administrators, at 83.
Cheryl McIlquham, Issue Paper #864, 1997 — 99 Budget, Single License Plate, Legislative Fiscal Bureau (May 22,1997), at 2.
In a May 24,1995, letter to the Legislative Joint Committee on Finance, Emil S. Thomas, Deputy Chief of Police, Madison Police Department, stated, "Police Officers utilize license plates for the basic purpose of identification. . .Requiring a front plate significantly improves the chance of an officer identifying a suspect leaving the scene of a crime as the officer responds to the scene. It also enhances the odds of a citizen witness correctly identifying the plate number."