Full opinion text
KANNE, Circuit Judge. In this civil rights lawsuit, a putative class action, plaintiffs claim that the drug interdiction unit of the Illinois State Police (ISP), Operation Valkyrie, has a practice of stopping, detaining, and searching African-American and Hispanic motorists based on their race and without legally sufficient cause or justification. The allegation before us, at its core, is that the ISP engages in the practice of racial profiling. Racial profiling is generally understood to mean the improper use of race as a basis for taking law enforcement action. Challenges to the practice of racial profiling have become increasingly prevalent; indeed, this suit is part of a larger effort to challenge the practice nationwide. Defendants-appellees deny that they engage in racial profiling, and claim that they instruct their officers not to use race in determining which motorists to stop, detain, and search. Plaintiffs filed suit in August 1994, in the United States District Court for the Northern District of Illinois. Defendants included the Director of the Illinois State Police, Terrance Gainer; the ISP Operation Valkyrie Coordinator, Michael Sny-ders; the District Commander of the ISP, Edward Kresl; and several individual ISP troopers. Plaintiffs alleged numerous violations of their rights and sought damages as well as declaratory and injunctive relief. They based their claims upon the Equal Protection Clause of the Fourteenth Amendment; the right to travel provided by the Privileges and Immunities Clauses of Article IV and the Fourteenth Amendment; the Fourth Amendment; Title VI of the Civil Rights Act of 1964 and the administrative regulations effectuating that Title; and a variety of related supplemental state law provisions. They also sought to impose supervisory liability for these violations upon several ISP personnel under 42 U.S.C. § 1983. Through a series of rulings spanning the five years of litigation below, the district court dismissed the right to travel claim and granted defendants’ motions for summary judgment on the equal protection and supervisory liability claims. Additionally, the court determined that plaintiffs lacked standing to obtain injunctive relief, declined to certify a class of Hispanic motorists stopped on the basis of race, denied plaintiffs’ motion to add a new named plaintiff to represent the Hispanic class, and denied one of plaintiffs’ discovery related motions. In response to these rulings, plaintiffs moved to voluntarily dismiss, with prejudice, their remaining claims. The court dismissed the Title VI regulatory claims pursuant to Rule 16 of the Federal Rules of Civil Procedure, but stated that, if plaintiffs elected to dismiss their remaining claims, the court would impose reasonable costs. Plaintiffs continued to request dismissal, thus the court issued an order dismissing plaintiffs’ Fourth Amendment, Title VI, and supplemental state law claims, with prejudice and pursuant to Rule 41 of the Federal Rules of Civil Procedure. Plaintiffs now appeal the grant of summary judgment on their equal protection and supervisory liability claims, the dismissal of named plaintiff Peso Chavez’s right to travel claim, the finding that they lacked standing to pursue injunctive relief, and the district court’s denial of their motions to add a new plaintiff, to certify a class, and to take certain discovery. Plaintiffs also challenge the propriety of requiring them to pay defendants’ costs as a precondition to dismissal. Before we review the procedural and substantive legal challenges raised in this appeal, we will describe the Operation Valkyrie program; detail the facts surrounding the stops, detentions, and searches of each of the named plaintiffs; introduce the statistics plaintiffs have presented in their effort to show that defendants engage in racial profiling; and summarize the relevant procedural history. I. History A. Operation Valkyrie The Illinois State Police run a drug interdiction program entitled “Operation Valkyrie.” The program is “designed to acquaint patrol officers with techniques which will enhance them capability to detect and apprehend drug couriers ... while focusing on the enforcement of highway safety regulations.” Operation Valkyrie: An Officer’s Guide to Drug Interdiction Techniques i. Since its inception in 1990, the ISP has assigned more than one hundred officers to Valkyrie teams that operate in eleven of the ISP’s twenty-one districts. Non-Valkyrie officers also receive Valkyrie training in order to familiarize them with drug-interdiction techniques. Master Sergeant Michael Snyders, the former statewide Operation Valkyrie Coordinator, testified that Valkyrie officers only stop vehicles for traffic enforcement reasons (i.e. for traffic violations or other threats to traffic safety). Once a vehicle is stopped, he explained, Valkyrie officers look for indicators of drug trafficking. These indicators are numerous — indeed there is a list of twenty-eight factors in the Operation Valkyrie training manual — and include such things as too little or too much luggage for the stated length of trip, maps from drug source cities or states, and air freshener. Officers are also trained to look for verbal and non-verbal signs of stress and deception, such as nervousness and an overly friendly demeanor. Snyders testified that when Valkyrie officers observe these indicators, they are trained to request consent to search the vehicle. In 1992, Valkyrie officers requested permission to search in approximately fourteen percent of motorist stops, and when requested, over ninety-eight percent of motorists granted consent. Plaintiffs allege that race plays into the Valkyrie officers’ decision to stop a motorist — what we will term “pre-stop profiling” — and into the decision to detain or search a motorist, and that no ISP policy prohibits troopers from using race as a factor in making these determinations. As evidence of this, plaintiffs assert that certain ISP drug interdiction training materials emphasize, through statistics, images, and examples, the alleged predominance of Hispanics among those highway travelers carrying illegal drugs. They also point to the testimony of Trooper Robert Cessna, who testified that a motorist’s race is one “indicator” that “you’ve got to keep in mind.” Plaintiffs further assert that Operation Valkyrie grants troopers substantial discretion to decide which motorists to stop and search. ISP training materials acknowledge that discretion can deteriorate into abusive practices, including racial discrimination. Plaintiffs argue that ISP procedures for addressing citizen complaints and reviewing trooper enforcement activity do not sufficiently curb an officer’s ability to impermissibly take race into account. When a complaint is filed, a case number is typically assigned, a case is opened, and the complaint is processed. If, however, ISP personnel determine that a complaint is not sufficient for further investigation or that another entity is already investigating the violation, no case is opened. The ISP will not “open a case” when a citizen complains that he was stopped on the basis of race and issued a traffic citation for an offense he did not commit because the ISP views this issue as one to be resolved by the courts. See Dep. of Teresa Kettel-kamp at 86-87 (former deputy director of the Division of Internal Investigation). Apparently, the ISP assumes that the motorist will go to traffic court and allege racial prejudice as a defense to the ticket. In addition, the ISP Office of Inspection and Audits does not investigate the issue of race in trooper enforcement activity. The ISP presented evidence that Valkyrie officers are taught not to use race in determining what motorists to stop, detain, and search. The training manual for Operation Valkyrie states that the “[ISP] has never endorsed, condoned or promoted the use of any profiling system in its interdiction program.” See Operation Valkyrie: An Officer’s Guide to Drug Interdiction Techniques i. Training sessions also included presentment of a videotape which emphasizes that drug couriers look “pretty much like everyone else,” that it is difficult to characterize smugglers on the basis of nationality, and that ISP officers must have a lawful reason to stop or search motorists. During the early years of the Valkyrie program, some ISP districts attempted to monitor trooper discretion by collecting data on the race of motorists searched by Valkyrie troopers. One reason for collecting such data, according to Snyders, was to respond to potential questions about whether officers were targeting motorists because of their race. This data was also used as a supervisory tool to ensure that team members were not concentrating on certain ethnic groups. Between 1990 and 1994, monthly statistics in District Six, one of the ISP districts to collect such data, demonstrated that African-Americans and Hispanics comprised over sixty percent of the motorists searched. B. The Stops and Searches 1. The Stop and Search Involving Peso Chavez Peso Chavez’s claim evolved out of the stop, search, and arrest of a white motorist, George Koutsakis. In November 1992, an Illinois state trooper, and Valkyrie officer, stopped Koutsakis for exceeding the sixty-five mile per hour speed limit. Kout-sakis was driving a red or burgundy rental car bearing California license plates, and had open maps, a mobile phone, and fast food wrappers in his vehicle. While the trooper was in the process of issuing a warning ticket, a second Valkyrie officer arrived (Trooper Graham) and walked his drug-detecting canine around the vehicle. The dog alerted, indicating the presence of drugs, and the subsequent search of Kout-sakis’s vehicle uncovered over two hundred pounds of marijuana in the trunk. Kout-sakis’s criminal defense attorney, Nancy Hollander, suspected that state troopers were stopping motorists based on skin tone or travel patterns, and decided to explore whether the stop of Koutsakis might have been pretextual. As part of her criminal defense strategy, she thus hired Chavez, a private investigator and New Mexico resident, to recreate the circumstances leading to Koutsakis’s stop and arrest. Chavez, who is Hispanic, emulated the circumstances surrounding Koutsakis’s stop and arrest, to see if he would be stopped by the Illinois State Police. He rented a red car with California license plates. On February 18, 1993, he placed open maps, fast food wrappers, a cellular phone, and a gym bag in the car, and proceeded to Interstate 80 (“1-80”). Katherine Austin, a white female from the Public Defenders’ Office, followed closely behind him in a separate car. Chavez and Austin traveled to the western edge of Bureau County, Illinois, and began driving east on 1-80. When Chavez’s vehicle passed State Trooper Larry Thomas, parked on the east-bound shoulder of 1-80 at mile post fifty-three, Trooper Thomas decided to follow it. Thomas followed Chavez’s vehicle for approximately twenty-four miles, or almost one-half hour, though he could not explain why he decided to do so. Chavez was not speeding; he traveled no faster than sixty miles per hour, although the speed limit was sixty-five. At one point, Thomas drove alongside Chavez’s vehicle and looked him in the face. Thomas learned that the car was a rental car after he had a license plate check run through the dispatcher Thomas stopped Chavez at about mile post seventy-seven, allegedly because Chavez failed to signal a lane change. Chavez testified that he did signal and denied committing any traffic violation. Austin, who had been following Chavez, agreed. Defendants conceded for the purposes of summary judgment that Chavez did not violate any traffic laws. Thomas approached the car and noticed several items inside, including Chavez’s small suitcase, several fast food bags, and an atlas. He also saw Chavez’s hands shaking and thought Chavez was nervous. Thomas requested Chavez’s driver’s license and registration, and' returned to his squad ear. Thomas was subsequently joined by Sergeant Dan Gillette, who had been monitoring traffic at mile post seventy-seven. Gillette claims that Thomas told him there was something funny about Chavez, that he smelled air freshener in the car and that he did not see any luggage. Gillette suggested that Thomas run a criminal history check and a check through the El Paso Intelligence Center (EPIC), a database that contains information about border crossings. Gillette then went over to Chavez’s vehicle and asked Chavez where he was going. Chavez replied he was going to Chicago for the day; this was not entirely true because Chavez had not yet decided whether he would go or not. To Gillette, Chavez appeared nervous and deceptive regarding his destination. Gillette also testified that he saw a road atlas and fast food wrappers in the car, and thought the car was too clean to have come from Albuquerque. Gillette returned to Thomas’s vehicle and Thomas informed him that Chavez’s license and registration were valid and that Chavez had no criminal history. Gillette told Thomas that he was still suspicious due to the numerous indicators of drug trafficking. Thomas issued Chavez a warning ticket based on the alleged failure to signal, and returned Chavez’s license and registration once he signed the citation. Thomas then asked Chavez for permission to search his car. Chavez did not consent to the search and stated that he wanted to leave. Based on the indicators, Gillette felt there was sufficient reason to detain Chavez for a canine walk around, and thus the officers detained Chavez to await the arrival of a canine unit. When Trooper Graham arrived with his police dog, Krott, Thomas asked Chavez if he would consent to a canine walk-around. Gillette testified that Chavez did not consent, though Thomas’s report said he did. The dog did not alert on the first walk-around. Chavez admits that he. became nervous during the encounter. Because it was a rental car, he had no knowledge of whether it had previously been used to transport drugs. He also feared that, if the search was unsuccessful, the troopers would become frustrated and plant evidence. The troopers conducted a second walk-around. Graham testified that this time the canine alerted, but Chavez did not see the alert. In response, Gillette asked Chavez to go sit in Officer Thomas’s vehicle. Gillette, Graham, and Trooper Robert Cessna (who went to the scene when radio traffic indicated that Chavez was suspicious) then proceeded to search Chavez’s car. The officers examined the car’s interior, trunk, and wheel wells, and the contents of Chavez’s luggage. The EPIC i-e-port then came back and indicated that Chavez’s rental car had made several border crossings during the previous year. The car was searched again, this time using flashlights, and this search included an examination of the engine. Again, the officers did not find any contraband. Finally, thirty-five to fifty-five minutes after he was stopped, Thomas told Chavez he was free to go. Thomas completed a field report regarding the search of Chavez’s vehicle and listed Chavez’s race as “white,” despite the fact that the report contained a listing for Hispanic. Although Chavez resides in New Mexico, plaintiffs allege that his business has a prominent Illinois nexus and Chavez is confident that he will travel to Illinois in the future. Nonetheless, Chavez was not stopped by the ISP on subsequent travel dates of February 25 and 27, 1993, and has not returned to Illinois since February 1993. 2. The Stops and Searches Involving Gregory Lee Gregory Lee, who is African-American, testified that he was unjustifiably stopped, searched, and detained three times in 1993. In late summer or early fall of 1993, Lee was driving west on 1-80 with his wife, who is also African-American, when an ISP officer stopped them. Lee says that he had not violated any traffic law. The officer requested consent to search the vehicle, and Lee gave his consent. The officer instructed Lee and his wife to step out of the car. He patted down Lee and indicated that he would pat down Mrs. Lee but then turned and searched the trunk instead. The officer found no contraband, and no ticket or warning was issued. In March 1993, Lee was driving on 1-80 near Orland Park, Illinois, with his friend, Mike, who is also African-American. ISP Trooper Robert Lauterbach stopped Lee and told him he was speeding, which Lee alleges is false. Trooper Lauterbach asked for Lee’s license and then asked him to step out of the car. Once Lee stepped out, the officer brought him back to the rear of the car and at the same time asked Mike to step out of the car. Lee asked the trooper what the problem was and the trooper said something about them looking suspicious. The officer patted them down; at some point, an unidentified second officer arrived. Lauterbach ordered Lee and his friend to kneel on the roadside, behind Lee’s vehicle, with their hands on their heads. While they were kneeling, Lauter-bach searched the car without Lee’s consent — he searched the front and back seat and the glove box — but found no contraband. The officer then returned Lee’s license and keys and allowed Lee and his friend to go. No warning or ticket was issued. In August 1993, Lee was driving on I-80, at the intersection of 1-57, when he was stopped by ISP Trooper Dale Fraher. Lee got out of the car and asked the officer if there was a problem. Fraher claimed that Lee’s car wheel was wobbling and that there was a problem with the license plate registration sticker, though plaintiff denies that there was anything wrong with either. After asking for and receiving Lee’s drivers’ license, Fraher asked if he could search Lee’s car, twice stating that one can never tell with “you people.” Lee consented; Fraher searched the car but found no contraband. Fraher then returned Lee’s license and allowed Lee to go without issuing a ticket or warning. Lee alleges that he travels on Illinois highways at least sixty times per year and that he intends to continue doing so. He contacted ACLU attorneys after seeing an article in the Chicago Defender discussing the lawsuit filed by Peso Chavez. The article included the ACLU’s phone number, indicating that they would be “willing to listen to anyone else subjected to questionable state police auto searches.” Stephen Thomas, ACLU Pulls Over State Police, Chicago Defender, Aug. 31, 1994. Lee contacted the ALCU be cause he felt that he was someone who had a similar experience and later became a party to the current lawsuit. C. The Statistics An ISP stop can generate several types of records. First, when an ISP officer makes a stop he must radio headquarters to convey selected information, including the state and license plate number of the vehicle stopped. Second, if the ISP officer issues a citation or a warning to one or more of the vehicle occupants, this fact is recorded in the “citations and warnings database.” This electronic database includes the name of the individual receiving the citation or warning as well as the basis for the action (such as speeding or an illegal lane change). Finally, in a limited number of circumstances an officer will complete a “field report.” Field reports are typically completed when contraband is found, when a custodial arrest is made, when canines are involved, or when there is damage to police equipment or injury to a trooper, though even in these circumstances they are not always completed. When ISP officers use Valkyrie skills or obtain information of interest to the Valkyrie program they are encouraged to fill out a field report and to mark it with a “V”— these are referred to as the “Valkyrie field reports.” At plaintiffs’ request, the defendants provided the citations and warnings and the field reports databases to Temple University’s Center for Public Policy. The Center analyzed this data and James Ginger and Martin Shapiro, plaintiffs’ experts, examined the Center’s results. Plaintiffs’ experts compared the percentage of whites, African-Americans, and Hispanics in the ISP databases with the percent that each race is present in the Illinois population, based on data from the 1990 Census, and present on Illinois roads, as estimated by the Nationwide Personal Transportation Survey (NPTS). In Shapiro’s opinion, the field reports indicated a systemic over-representation of African-Americans and individuals of Hispanic origin in Valkyrie police activity. Ginger concluded that officers engaging in drug interdiction efforts selected a significantly higher percentage of Hispanic drivers for discretionary enforcement efforts — defined as activities which give the officer large amounts of latitude in determining what, if any, action to take — than did other ISP officers. D. Procedural History More than five years of litigation preceded this appeal. Peso Chavez filed this. suit as a “civil rights class action” in the U.S. District Court for the Northern District of Illinois on August 30, 1994. After a search for additional plaintiffs, Gregory Lee was one of several people "granted leave to join the suit. On November 7, 1995, plaintiffs moved to certify a class of all persons who in the past had been, and in the future would be, unlawfully stopped, detained, or searched by the ISP in accordance with their practice of improperly stopping motorists on the basis of race. On May 23, 1996, plaintiffs filed a third amended complaint, adding an additional plaintiff and fourteen defendants. Plaintiffs subsequently filed a fourth amended complaint in September 1996, dropping seven of the newly named defendants. The original deadline for the completion of fact discovery was December 29, 1995; at plaintiffs’ request, this deadline was moved to March 31, 1996, then to May 24, 1996, and eventually to August 30, 1997. Expert discovery closed on November 13, 1998. On February 9, 1996, the district court dismissed plaintiffs’ right to travel claims under Rule 12(b)(6) of the Federal Rules of Civil Procedure. On November 5, 1998, the district court granted the defendants’ motion for summary judgment on the equal protection and certain of the supervisory claims and granted qualified immunity to several ISP officers on the Fourth Amendment claims. The court also declined to certify a class of all motorists unlawfully stopped due to their race, because the class certification motion appeared to be premised on the defunct equal protection claim. The court stated that plaintiffs would be allowed to renew their motion if they elected to pursue certification based on the claims that survived summary judgment. On April 2, 1999, plaintiffs thus sought to certify “a class consisting of all persons of Hispanic race or color” who had been or would be stopped, detained, or searched by the ISP in violation of Title VI. The same day, twenty months after the close of fact discovery, plaintiffs also sought leave to add Christopher Jimenez as an additional named plaintiff. The court found that the named plaintiffs did not have standing to pursue injunctive relief under Title VI, and thus declined to certify a class of Hispanic motorists with respect to the Title VI claims. The district court also denied plaintiffs’ motion to amend their complaint to add Jimenez as a named plaintiff. In February 1997, the plaintiffs served the Illinois Secretary of State with a subpoena for electronic data on licensed Illinois drivers. The Secretary determined that the plaintiffs were required to pay the statutory rate for provision of such information, and calculated the charge at $160,200. Plaintiffs objected that the charge was excessive, and they argued that they should only be required to pay the cost incurred by the Secretary in providing the information. The court found that the statutory fee of two cents per record was reasonable and overruled plaintiffs’ objections. In August 1999, in response to the court’s orders granting summary judgment on a number of the plaintiffs’ claims and finding that the plaintiffs lacked standing to pursue their Title VI claims for equitable relief, the plaintiffs moved to voluntarily dismiss with prejudice their remaining claims. They requested leave to amend their complaint pursuant to Rule 15(a) of the Federal Rules of Civil Procedure in order to eliminate the Fourth Amendment claims, supplemental state law claims, and Title VI statutory claims. They also moved to dismiss their Title VI regulatory claims pursuant to Rule 16(c)(1). Plaintiffs stated that they did not want to go to trial on these individual damages claims, because such a trial could not provide their desired remedy: injunc-tive relief against the alleged racial profiling. The court denied plaintiffs’ request for leave to amend under Rule 15(a), dismissed the Title VI regulatory claims pursuant to Rule 16, and advised plaintiffs that, if they elected to dismiss claims pursuant to Rule 41(a)(2), the court would impose reasonable costs. Plaintiffs opposed the imposition of costs, but the district court ruled that “an award of reasonable costs will be a condition precedent to entry of an order permitting the plaintiffs to voluntarily dismiss their remaining claims.” Chavez v. Ill. State Police, No. 94 CV 5307, 1999 WL 754681, *6 (N.D.Ill. Sept. 9, 1999). On September 16, 1999, the court granted plaintiffs’ motion to voluntarily dismiss the remaining claims with prejudice, pursuant to Rule 41(a)(2). Plaintiffs filed a notice of appeal. In October 1999, defendants moved for immediate payment of all costs. The court granted the motion and taxed costs at $22,800.72. The court reiterated that payment of costs was a condition precedent to its dismissal order, and that the costs award would need to be paid regardless of the result on appeal. Following that decision, the plaintiffs moved to alter or amend the judgment pursuant to Rule 59. Plaintiffs also moved for a stay of payment pending appeal. On January 13, 2000, the district court denied plaintiffs' motion to alter or amend the judgment, but granted the stay of payment. On February 18, 2000, plaintiffs filed their second notice of appeal, regarding the manner in which costs may be taxed as a condition on voluntarily dismissal with prejudice. II. Analysis Plaintiffs allege that defendants are liable under 42 U.S.C. § 1983, which "requires proof that the defendants were acting under color of state law and that the defendants' conduct violated the plaintiff's rights, privileges, or immunities secured by the Constitution or laws of the United States." Lanigan v. Vill. of E. Hazel Crest, Ill., 110F.3d 467, 471 (7th Cir.1997) (citations omitted). There is no dispute that the defendant officers were acting under color of state law, thus we must examine whether defendants' actions rio-lated plaintiffs' constitutional or statutory rights. We begin by reviewing the district court's procedural rulings: first, the district court's refusal to certify a class with respect to the plaintiffs' equal protection claims; second, the district court's denial of plaintiffs' motion to amend their complaint to add a new plaintiff; and third, the district court's ruling on a discovery matter. We then review plaintiffs' substantive claims, the first alleging violations of the equal protection clause of the Fourteenth Amendment, and the second alleging violations of the right to travel. Next considered is the grant of summary judgment to defendant Michael Snyders on the issue of supervisory liability, followed by an analysis of the plaintiffs' challenges to the resolution of their Title VI claims. Finally, we address the plaintiffs' challenge to the district court's order making the payment of costs a condition of voluntary dismissal. A. Jurisdiction This court has jurisdiction to hear appeals from "final decisions" of the federal district courts. 28 U.S.C. § 1291. An order becomes final or appealable upon the enti~y of a final judgment. See ITOFCA, Inc. v. MegaTrans Logistics, Inc., 235 F.3d 360, 363-64 (7th Cir.2000). "The proper appeal of a final judgment renews all issues previously pleaded and resolved by the trial court in litigation." Grun v. Pneumo Abex Corp., 163 F.3d 411, 419 (7th Cir.1998) (citing In re Grabill Corp., 983 F.2d 773, 775 (7th Cir.1993)), cert. denied, 526 U.S. 1087, 119 S.Ct. 1496, 143 L.Ed.2d 651 (1999). Defendants argue that the plaintiffs improperly manufactured appellate jurisdiction by asking the district court to voluntarily dismiss their claims, and thus argue that we have no jurisdiction to hear the instant appeal. We disagree. While we may not review claims that were dismissed pursuant to plaintiffs' request for voluntary dismissal with prejudice, we will review the district court's rulings with respect to the remainder of plaintiffs' claims. See Gray v. Dane County, 854 F.2d 179, 182 (7th Cir.1988). B. The Procedural Claims 1. Standard of Review Plaintiffs challenge a number of procedural rulings made by the district court over the course of this litigation. We will overturn these rulings only if we determine that the court abused its discretion. " `Abuse of discretion' means something more than our belief that we would have acted differently if placed in the circumstance confronting the district judge." Anderson v. United Parcel Serv., 915 F.2d 313, 315 (7th Cir.1990). "The district court's decision must strike us as fundamentally wrong for an abuse of discretion to occur." Id. However, we must still "scrutinize the district court's determination to ensure that it invoked the correct legal standards and that its findings of fact are not clearly erroneous.” Salgado by Salgado v. General Motors Carp., 150 F.3d 735, 739 (7th Cir.1998). 2. Denial of Class Certification Plaintiffs originally filed this suit as a “civil rights class action” on August 30, 1994. On November 7, 1995, they filed a motion for the certification of a class of persons who in the past had been, and in the future would be, unlawfully stopped, detained, and searched pursuant to defendants’ practice of stopping, detaining, and searching individuals traveling on highways in Illinois on the basis of race and without legally sufficient cause or justification. When the magistrate judge considered this motion he found that, in light of the court’s previous rulings in favor of the defendants’ motion for summary judgment on the plaintiffs’ equal protection claims, the motion for class certification was moot. See Chavez v. Ill. State Police, No. 94 CV 5307 (N.D.Ill. Sept. 25, 1997). He thus recommended the denial of the motion for certification of plaintiffs’ class without prejudice, with leave to reinstate the motion with respect to any claims that survived summary judgment. The district judge agreed and found that “it would be wholly illogical to consider the motion,” considering that the class certification claim appeared to be premised on an equal protection claim that was no longer viable. Judge Manning stated that “[a] decision that the named plaintiffs’ claims lack merit may disqualify them as proper class representatives, thereby mooting the class certification question.” Chavez, 27 F.Supp.2d at 1084 (citing Cowen v. Bank United of Tx., 70 F.3d 937, 941 (7th Cir.1995)). The court stated that plaintiffs would be allowed to renew their motion if they elected to pursue certification based on the claims that survived summary judgment. Thus, in early 1999, plaintiffs sought certification of “a class consisting of all persons of Hispanic race or color” who had been or would be stopped in violation of Title VI. Both the magistrate judge and the district court judge found that Chavez did not have standing to pursue prospective relief. The district court judge determined that Chavez could not, therefore, represent a class of Hispanic motorists seeking such relief and dismissed plaintiffs’ motion. While plaintiffs assert that this was error, the plaintiffs requested and were granted a voluntary dismissal of their Title VI claims. We will thus not review the district court’s refusal to certify a class with respect to those claims. Plaintiffs argued before the district court, and continue to assert on appeal, that they were entitled to a ruling on the motion for class certification before the district court considered the defendant’s motion for partial summary judgment on the plaintiffs’ equal protection claims. The district court disagreed. The court noted that a ruling on summary judgment may properly precede a ruling on a motion for class certification. Id. at 1085. Though recognizing that “an accelerated merits disposition may be preferable when the court considers the merits before ruling on a motion for class certification,” the court stated that the delay was “largely attributable to the plaintiffs.” Id. We conduct a deferential review of the denial of plaintiffs’ motion to certify a class. Under the Federal Rules of Civil Procedure, “a district court has broad discretion to determine whether certification of a class-action lawsuit is appropriate.” Mira v. Nuclear Measurements Corp., 107 F.3d 466, 474 (7th Cir.1997) (citing Ret. Chi. Police Ass’n v. City of Chi., 7 F.3d 584, 596 (7th Cir.1993)). In most cireum-stances, a judge should determine whether to grant or deny certification prior to ruling on the merits, as indicated by the text of Rule 23: “As soon as practicable after the commencement of an action brought as a class action, the court shall determine by order whether it is to be so maintained.” Fed.R.Civ.P. 23(c). This is the preferred policy as “the propriety of class certification does not depend on the outcome of the suit.... It is therefore difficult to imagine cases in which it is appropriate to defer class certification until after decision on the merits.” Bieneman v. City of Chi., 838 F.2d 962, 964 (7th Cir.1988) (citations omitted). We have since noted, however, that such situations do exist. If “as soon as practicable” occurs after a case is already “ripe for summary judgment” then it might be proper for a judge to consider a motion for summary judgment prior to considering a motion for class certification. Cowen, 70 F.3d at 941 (citations omitted). Where this situation occurs, if the court determines that the named plaintiffs’ claims lack merit, such a decision “ordinarily, though not invariably, ... disqualifies the named plaintiffs as proper class representatives,” thus resolving the issue of class certification. Cowen, 70 F.3d at 941 (citations omitted). As noted by the district court, plaintiffs requested and were granted numerous stays with respect to the summary judgment motions before the court. In response to plaintiffs’ frustration with the delayed consideration of them class certification motion, the district court simply noted that the plaintiffs’ actions caused the delay. Yet this response obscures the fact that it was the district court’s decision to consider the summary judgment motions before the class certification motion that led to the delayed consideration of the latter. Indeed, this is why it is preferable to review a motion for class certification first; a quick disposition on the merits is often not possible. Nonetheless, “[wjhile we agree that it is the better policy for the district court to dispose of a motion for class certification promptly and before ruling on the merits of the case, the failure to follow this preferred procedure does not necessarily amount to reversible error.” Mira, 107 F.3d at 475. We must thus examine whether the delay in ruling was such that it rose to reversible error. The denial of class certification was premised on the district court’s finding that the named plaintiffs lacked standing to seek injunctive relief, a finding partially linked to the fact that Chavez had not returned to Illinois and had not been stopped since the original stop in 1993. Plaintiffs allege that, if the district court had ruled on class certification as soon as practicable, the mootness of Chavez’s claim would not have prevented the class members from proceeding. Yet, even if this were true, the class would not have prevailed on the merits. The plaintiffs’ litigation strategy was to present statistics as the basis for their claims, and as we explain in Parts II.D.l.c and II.D.2 below, these statistics are not sufficient to prove a violation of the equal protection clause of the Fourteenth Amendment. This determination would have been made regardless of whether this lawsuit was certified as a class action or not. “[Although the procedural method chosen by the district judge is not the one favored under Rule 23, we refuse to disturb [her] denial of class certification because [ ] the plaintiffs’ underlying claims clearly lack merit, as evidenced by our affirmance of the district court’s summary judgment rulings.... ” Myra, 107 F.3d at 475. We thus find that the district court did not abuse its discretion in denying the plaintiffs’ motion for class certification with respect to the equal protection claims. S. Denial of Motion to Add Christopher Jimenez as a Class Representative Plaintiffs also challenge the district court’s denial of their motion to add Christopher Jimenez as a class representative. On February 6, 1996, Christopher Jimenez, who is Hispanic, and his fiance, Stacie Tiffany, who is white, were driving northbound on 1-55 in Sangamon County, Illinois, in Tiffany’s car. Tiffany was driving and admits that she was exceeding the speed limit. Jimenez alleges that ISP Trooper Robert Jennings, a Valkyrie officer, was parked at the side of the road looking at them with binoculars. Trooper Jennings admits that he has been able to detect the race of an occupant of a vehicle by using his binoculars in the past. Jennings saw but did not stop “hundreds” of other speeders that day. Jennings Dep. at 42. He explained that Tiffany’s speeding and the fact that a male passenger was slumping in the front seat while wearing a baseball cap drew his attention to Tiffany’s vehicle. Jennings followed the vehicle and saw Tiffany fail to signal prior to changing lanes. He then stopped her, stating that he did so because she was speeding and failed to signal properly. He asked both Tiffany and Jimenez for their drivers’ licenses and asked Tiffany questions about the nature of her relationship with Jimenez. According to Trooper Jennings, he is more likely to ask questions about the relationship between vehicle occupants if they are of different races. Although Jennings testified that he did not have a “suspicion” or a “strong feeling” that contraband was in the vehicle, he asked Tiffany for her permission to search her car. Plaintiffs say Jennings justified his request by explaining that “in the past we had made drug seizures from mixed race couples.” Jennings Dep. at 76. Tiffany consented. Jennings inspected and patted down the soft-surface bags in the trunk and patted down the area where the convertible’s top is stored. He did not discover any contraband. Jimenez filed a written complaint with the ISP one week later, which the ISP deemed unfounded. Nonetheless, Jennings received counseling to make him aware that what he says can impact negatively upon the public, regardless of his intent. While Jimenez resides in Michigan, plaintiffs allege that he travels on Illinois highways several times per year, although his prior experience with the ISP has so intimidated him that he avoids 1-55. The plaintiffs identified Jimenez as part of the putative plaintiff class in July 1996, when they filed their fourth amended class action complaint. Almost three years later, on April 2, 1999, the plaintiffs moved to add Jimenez as a new named plaintiff pursuant to Rules 15(a) and 21 of the Federal Rules of Civil Procedure. The plaintiffs’ motion was untimely, to say the least: fact discovery had closed in August 1997, a final pre-trial order was scheduled to be filed on July 15, 1999, and the trial date was set for September 7, 1999. Magistrate Judge Bobrick denied the plaintiffs’ motion. Although he concluded that the plaintiffs met the literal standard for join-der set forth in Rule 20(a), he determined that the court had discretion to deny a motion for joinder “where it would cause delay, prejudice, or expense” and found that adding a plaintiff would do all of those things. Chavez v. Ill. State Police, No. 94 CV 5307, slip op. at 2 (N.D. Ill. June 4, 1999). He noted that plaintiffs had known about Jimenez’s claims for nearly three years but offered no explanation as to why they were unable to add Jimenez as a named plaintiff earlier. Plaintiffs objected to the magistrate’s order, but on appeal, the district judge found that the order was not clearly erroneous, agreeing that join-der of Jimenez would be prejudicial and that the plaintiffs delayed in seeking to add him as a named plaintiff. The district judge echoed the magistrate judge's observation that "while motions to amend a complaint are ordinarily granted, this is not an ordinary case." Chavez v. Ill. State Police, No. 94 CV 5307, 1999 WL 515483, at *5 (N.D.Ill. July 15, 1999). Again, we review the district court's ruling for abuse of discretion. No one disputes that joinder of Jimenez would be proper under the text of Rule 20. What is contested is whether the district court abused its discretion to deny leave to amend the complaint so that plaintiffs could join a party. Where a responsive pleading has already been served, "a party may amend the party's pleading only by leave of court or by written consent of the adverse party; and leave shall be freely given when justice so requires." Fan. R.Crv.P. 15(a). However, "leave to amend need not be given if there is an apparent reason not to do so, such as `undue delay, bad faith or dilatory motive on the part of the movant, repeated failure to cure deficiencies by amendments previously allowed, undue prejudice to the opposing party by virtue of allowance of the amendment, [or] futility of amendment.'" Payne v. Churchich, 161 F.3d 1030, 1036 (7th Cir.1998), cert. denied, 527 U.S. 1004, 119 S.Ct. 2339, 144 L.Ed.2d 236 (1999) (quoting Foman v. Davis, 371 U.S. 178, 182, 83 S.Ct. 227, 9 L.Ed.2d 222 (1962)). Similsrly, we also accord wide' discretion to a district court's decision concerning the joinder of parties. See Intercom Research Assoc., Ltd. v. Dresser Indus., Inc., 696 F.2d 53, 56 (7th Cir.1982). We have recognized that this discretion allows a trial court to consider, in addition to the requirements of Rule 20, " `other relevant factors in a case in order to determine whether the permissive joinder of a party will comport with the principles of fundamental fairness.'" Id. at 58 (quoting Desert Empire Bank v. Ins. Co. of N. Am., 623 F.2d 1371, 1375 (9th Cir.1980)). If joinder would create "prejudice, expense or delay" the court may deny the motion. CHARLES Ai~ WRIGHT, ET AL, FEDERAL PRACTICE AND PROCEDURE § 1652 at 396 (2001). The district court conducted a reasoned analysis of whether joinder was appropriate and determined that it would be fundamentally unfair to the defendants to add Jirnenez as a named plaintiff. The court found that three factors weighed in favor of granting the motion: plaintiffs had a legitimate reason for requesting joinder in that they wished to substitute Jimenez for one of the formerly named Hispanic plaintiffs who had been dropped from the action; Jimnenez was already party to the action and was thus closely related; and jurisdiction would not be affected. Several additional factors, however, weighed in favor of denying the motion. The court determined that joinder would be heavily prejudicial to the defendants, as it would require, at a minimum, further deposition testimony. Although Jimenez had been deposed in 1997, it was by telephone, and was much less searching than the depositions of the named plaintiffs. While plaintiffs argued that they would allow additional depositions of Jimenez, the court dismissed this offer: Contrary to the plaintiffs' position throughout much of this case, discovery deadlines do not exist only to be extended. The court is entitled both to set deadlines and to expect that they will be honored, especially when the plaintiffs are before the court in 1999 shortly before trial seeking to extend a 1997 cut off based on events happening and known to them in 1996. Chavez, 1999 WL 515483, at *3~ The other factors weighing in favor of denying the motion were that Jimenez clearly had notice of the pending action yet plaintiffs did not attempt to join him earlier. "The plaintiffs knew of Jimenez and his claims for nearly three years, and for over one year before the close of fact discovery in 1997 but waited until approximately two months prior to trial to seek to add him as a plaintiff. If this is not delay, nothing is." Id. at *4~ The plaintiffs proffered explanation for this delay-that they were waiting for the resolution of a discovery related interlocutory appeal to this Court-was not presented to the magistrate judge and was properly dismissed by the district court. While plaintiffs assert that delay alone is an insufficient reason to deny their proposed amendment, there is a "a sufficient basis for denial of leave to amend when the delay has caused the opposing party undue prejudice." Textor v. Bd. of Regents of N. Ill. Univ., 711 F.2d 1387, 1391 (7th Cir.1983). We find that the district court judge did not abuse her discretion in denying the plaintiffs' motion to amend their complaint to add Jimenea as a named plaintiff~ 4. Conditioning Third Party Discovery on Payment of $160,000 On February 9, 1997, the plaintiffs served a subpoena on the Illinois Secre~ tary of State seeking production of eight million electronically stored records con-taming names, addresses, and related information for Illinois licensed drivers. Plaintiffs intended to use this information as a basis for statistical analysis in support of their Title VI claims. The Secretary of State objected to the subpoena, noting that the plaintiffs had not paid the statutorily required fee. Plaintiffs asserted that they had assumed the role of private attorneys general, and therefore should not have to pay the fee charged to private entities; instead, they argued that they should be treated as a governmental entity and pay only the actual cost for the information. When plaintiffs then moved to compel production, the magistrate judge denied the motion. See Chavez v. Ill. State Police, No. 94 CV 5307 (N.D.Ill. March 6, 1997). The district judge reviewed the magistrate's ruling and concluded that it was proper. See Chavez v. Ill. State Police, No. 94 CV 5307 (N.D.Ill. Jan. 14, 1999); Chavez v. Ill. State Police, No. 94 CV 5307 (N.D.Ill.Dec. 30, 1998). The defendants' motion to quash the subpoena was subsequently granted. See Chavez v. Ill. State Police, No. 94 CV 5307 (N.D.Ill. Jan. 28, 1999). As we have already noted, plaintiffs' Title VI claims are not before the court. Even if the requested data were intended to support the equal protection or right to travel claims, however, all discovery issues are moot in light of our disposition of these claims. Thus we need not review this issue. C. Lee's Identification of the ISP Troopers As an initial matter, defendants contend that Troopers Lauterbach and Fraher did not stop Lee, and ask for a dismissal based on the threshold unreliability of Lee's eyewitness identifications. Lee was not issued a citation or warning, thus he received no documentation of the stops. To determine the names of the officers who had stopped him, he looked at an array of photographs of Illinois State Police personnel, assembled by the ISP. Lee viewed these photos on two separate occasions, the first was about seventeen months after he was allegedly stopped by Fraher and over twenty-three months after he was allegedly stopped by Lauter-bach. On both occasions, Lee identified Lauterbach and Fraher as the ISP troopers who stopped, detained, and searched him in March and August of 1993, respectively. The ISP denies that these stops ever occurred. First, Lauterbach and Fraher claim that they do not recall stopping, detaining, or searching Lee. Second, the ISP states that they have no record of any traffic stop of Lee by Lauterbach or Fraher, and no record of either of these officers issuing Lee a citation or warning. Third, defendants contend that the officers were not patrolling the relevant roads on the dates Lee alleges he was stopped. Finally, the ISP claims that Lee's identifications of Lauterbach and Fraher are inherently unreliable, pointing to allegedly serious deficiencies in Lee's identifications of the pertinent officers. With respect to the first argument, the officers do not claim that they did not stop Lee, only that they do not recall doing so. They have produced no evidence definitively establishing that they were not present when Lee was stopped. Second, the ISP has admitted that records are not generated for all stops; without issuance of a citation or warning a record might not be generated. Third, Fraher testified that he patrolled 1-80 at the relevant time. While ISP records indicate that Lauter-bach was not working during part of the time period in which he is alleged to have stopped Lee, and that during the remainder of this period he was patrolling other roads, the ISP has admitted that troopers sometimes stop vehicles outside their patrol areas. Finally, we can not conclude that Lee's identifications are so flawed as to be inherently unreliable. The district court concluded that Lee's testimony created a genuine question of material fact and was thus sufficient to withstand summary judgment. See Chavez v. Ill. State Police, 27 F.Supp.2d 1053, 1079 (N.D.Ill.1998). We agree. While Lee's descriptions of troopers Lauterbach and Fraher contain certain inaccuracies, we will not resolve credibility disputes on a motion for summary judgment. See Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986); Ritchie v. Glidden Co., 242 F.3d 713, 723 (7th Cir.2001). Thus, we proceed to the merits of the plaintiffs' equal protection claims. D. The Fourteenth Amendment Equal Protection Claims In November 1998, after over four years of litigation, the district court granted the defendants’ motion for summary judgment on the plaintiffs’ equal protection claims. We review de novo grants of summary judgment. See Myers v. Hasara, 226 F.3d 821, 825 (7th Cir.2000). Summary judgment is proper when “the pleadings, depositions, answers to interrogatories, and admissions on file, together with the affidavits, if any, show that there is no genuine issue as to any material fact and that the moving party is entitled to a judgment as a matter of law.” Fed. R.CivP. 56(c); see also Celotex Corp. v. Catrett, 477 U.S. 317, 322-23, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986). In determining whether a genuine issue of material fact exists, we construe all facts and inferences in the light most favorable to the non-moving party, drawing all reasonable and justifiable inferences in favor of that party. See Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 255, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986). If, however, the record as a whole “could not lead a rational trier of fact to find for the non-moving party, there is no ‘genuine issue for trial.’ ” Matsushita Elec. Indus. Co. v. Zenith Radio Corp., 475 U.S. 574, 587, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986); see also Lindemann v. Mobil Oil Corp., 141 F.3d 200, 294 (7th Cir.1998). Plaintiffs assert that the ISP and individual ISP officers utilize impermissible racial classifications in determining whom to stop, detain, and search. Were this proven, it would amount to a violation of the Equal Protection Clause of the Fourteenth Amendment. See Whren v. United States, 517 U.S. 806, 813, 116 S.Ct. 1769, 135 L.Ed.2d 89 (1996) (“[T]he Constitution prohibits selective enforcement of the law based on considerations such as race.... [T]he constitutional basis for objecting to intentionally discriminatory application of laws is the Equal Protection Clause.”). The Supreme Court, as well as federal courts across the country, have begun to address the potential implications of racial profiling. See Illinois v. Ward-low, 528 U.S. 119, 120 S.Ct. 673, 681 n. 10, 145 L.Ed.2d 570 (2000) (discussing the conclusion of the New Jersey Attorney General that “minority motorists have been treated differently than non-minority motorists during the course of traffic stops on the New Jersey Turnpike”); United States v. Montero-Camargo, 208 F.3d 1122, 1135 (9th Cir.2000) (en bane) (discussing “[s]tops based on race or ethnic appearance”); Martinez v. Vill. of Mount Prospect, 92 F.Supp.2d 780, 782 (N.D.Ill.2000) (“Racial profiling of any kind is anathema to our criminal justice system.... ”); United States v. Leviner, 31 F.Supp.2d 23, 33 (D.Mass.1998) (“Motor vehicle offenses, in particular, raise deep concerns about racial disparity.”). Even civil rights litigation must, however, satisfy the requirements of our equal protection jurisprudence. To show a violation of the Equal Protection Clause, plaintiffs must prove that the defendants’ actions had a discriminatory effect and were motivated by a discriminatory purpose. See Pers. Adm'r of Mass. v. Feeney, 442 U.S. 256, 272-74, 99 S.Ct. 2282, 60 L.Ed.2d 870 (1979); Arlington Heights v. Metro. Housing Dev. Corp., 429 U.S. 252, 264-66, 97 S.Ct. 555, 50 L.Ed.2d 450 (1977); Washington v. Davis, 426 U.S. 229, 239-42, 242, 96 S.Ct. 2040, 48 L.Ed.2d 597 (1976). We examine each element in turn. 1. Discriminatory Effect To prove discriminatory effect, the plaintiffs are required to show that they are members of a protected class, that they are otherwise similarly situated to members of the unprotected class, and that plaintiffs were treated differently from members of the unprotected class. See Greer v. Amesqua, 212 F.3d 358, 370 (7th Cir.2000), cert. denied, - U.S. -, 121 S.Ct. 568, 148 L.Ed.2d 487 (2000); Johnson v. City of Fort Wayne, Ind., 91 F.3d 922, 944-45 (7th Cir.1996). Chavez and Lee may show that the ISP treated them differently than other similarly situated individuals by naming such individuals or through the use of statistics, an issue which we explore in greater depth below. See, e.g., United States v. Armstrong, 517 U.S. 456, 467, 116 S.Ct. 1480, 134 L.Ed.2d 687 (1996) (noting that the similarly situated requirement was met by the "indisputable evidence" in Hunter v. Underwood, 471 U.S. 222, 105 S.Ct. 1916, 85 L.Ed.2d 222 (1985), that Blacks were 1.7 times as likely as whites to suffer disenfranchisement under the law in question). a. Naming a Similarly Situated Individual Lee did not attempt to name a similarly situated individual who was not stopped or searched. Chavez alleges that Katherine Austin-the white female from the public defender's office who was following him at the time of his stop-was a similarly situated individual treated differently. To determine whether Austin was similarly situated to Chavez we "must look at all relevant factors, the number of which depends on the context of the case." Radue v. Kimberly-Clark Corp., 219 F.3d 612, 617 (7th Cir.2000). While we have repeatedly discussed the similarly situated requirement in the context of employment discrimination cases, these discussions are rarely extensive and do not provide any magic formula for determining whether someone is similarly situated. This is due, seemingly, to the essentially factual nature of the inquiry. Different factors will be relevant for different types of inquiries-it would be imprudent to turn a common-sense inquiry into a complicated legal one. In determining who is similarly situated, we have also been careful not to define the requirement too narrowly. See, e.g., Freeman v. Madison Metro. Sch. Dist., 231 F.3d 374, 382-83 (7th Cir.2000); cf. Radue, 219 F.3d at 619 (noting that the similarly situated requirement requires employees to demonstrate that they shared "common features essential to a meaningful comparison" to ensure that the employee who received the more favorable treatment was similarly situated). Defendants allege that George Koutsak-is-the individual stopped by the ISP whom Chavez was emulating-was a similarly situated individual who was treated the same as Chavez. The district court agreed, and determined that Chavez failed to show that he was treated any differently than a similarly situated white motorist. See Chavez v. Ill. State Police, 27 F.Supp.2d 1053, 1067 (N.D.Ill.1998). The district court found that Austin was not similarly situated because she was female, drove a different color car with a non-California plate, did not have the same items visible in her car, and did not receive a warning ticket. See id. The court also stated that “the fact that [Austin] was following Chavez essentially prevented Trooper Thomas from subjecting her to the same treatment as Chavez — he was engaged with Chavez at the time.” Chavez v. Ill. State Police, No. 94 CV 5307, slip op. at 22 (N.D.Ill. July 10, 1997). We do not agree with the district court’s treatment of this issue. The relevant inquiry is whether a similarly situated individual was treated differently than the plaintiff, not whether one white motorist was subjected to the same unlawful treatment. Allowing defendants to escape liability for discriminating against Hispanics simply because they occasionally mistreat white motorists would dismantle our equal protection jurisprudence. The fact that Koutsakis was also stopped is simply irrelevant to the inquiry of whether Chavez has shown that a similarly situated individual was treated differently. Quite to the contrary of defendants’ and the district court’s assertions, Chavez and Austin were similarly situated in all pertinent respects. Both were driving down the same stretch of 1-80 at the same time, and neither committed a traffic violation (defendants have conceded that Chavez did not commit a violation for the purpose of summary judgment). The factors that distinguish Austin from Chavez do not prevent her from being similarly situated. First, the ISP can not legally decide whom to stop on the basis of gender any more than they can do so on the basis of race, thus the fact that Austin is female is not pertinent. Second, nothing in the record indicates that Trooper Thomas stopped Chavez because he was driving a red car, or because he was driving a rental car, or because it was a car with California plates. To the contrary, the ISP asserts that Valkyrie officers do not stop motorists on the basis of these variables, and plaintiffs have agreed. Third, the objects inside Chavez’s vehicle that raised officer suspicion — i.e. the small suitcase, fast food bags, and atlas — were not visible until after Chavez was pulled over, thus they could not have been the basis for the stop. Finally, the fact that Thomas was engaged with Chavez does not prevent Austin from being similarly situated. The whole point of the plaintiffs’ claim is that after thirty minutes of trailing the two vehicles, Thomas stopped Chavez, who is Hispanic, rather than Austin, who is white. We thus find that Austin is a similarly situated individual of an unprotected class who was treated differently than Chavez. That Lee has not been able to name a similarly situated individual treated differently does not, however, end our review of his claims. Plaintiffs attempt to show that similarly situated individuals were treated differently than both Chavez and Lee through the use of statistics. The district court would not allow plaintiffs to use statistics for this purpose, based upon that court’s interpretation of United States v. Armstrong, 517 U.S. 456, 116 S.Ct. 1480, 134 L.Ed.2d 687, a recent Supreme Court case addressing the effects prong of the equal protection t