This direct criminal appeal returns us to a well-traveled road: the constitutionality of a roving border patrol stop on New Mexico’s Highway 185. The Defendant-Appellant, Roberto LopezAMartinez (“Lopez-Martinez”), appeals from the district court’s denial of his suppression motion. Because we concur with the court’s determination that the U.S. Border Patrol Agent demonstrated the requisite reasonable suspicion necessary under the Fourth Amendment to stop Lopez-Martinez’s vehicle and to inquire about the citizenship of his passengers, we affirm.
I.
This case arose when U.S. Border Patrol Agent Dale Jones (“Agent Jones”) stopped Lopez-Martinez’s van in Radium Springs, New Mexico, and discovered four undocumented aliens riding in the vehicle. At 10:00 a.m. on June 20, 1992, while on routine patrol, Agent Jones observed a van and a sedan exit Interstate 25 from the northbound lanes at the Radium Springs exit — less than ten miles south of the Las Cruces immigration checkpoint on Interstate 25 and less than sixty miles from the United States-Mexico border. Travelling in close proximity to one another, the two vehicles turned west on Route 157 and headed toward Highway 185, a north-south thoroughfare that runs parallel to Interstate 25. This stretch of Highway 185 is considered a notorious route by which to circumvent the Interstate 25 checkpoint north of Las Cruces.
Agent Jones initially noticed the two vehicles while he was driving east on Route 157. He promptly turned west, in the direction of the vehicles, and drove his unmarked border patrol vehicle between the van and the sedan. When Agent Jones passed the sedan, he noticed four Hispanic male passengers. Agent Jones also noted that the two vehicles’ license plates indicated that the vehicles were registered in Northern New Mexico. In addition, after Agent Jones passed the sedan in order to drive between the two vehicles, the sedan dropped back approximately 100 yards. Agent Jones followed the van as it turned north on Highway 185; the sedan followed behind.
Given the close proximity in which the two vehicles had been travelling despite the absence of traffic, Agent Jones surmised that the van and the sedan were travelling in tandem. He grew more suspicious of their enterprise when he noted that both vehicles drove 30 miles per hour along Highway 185 in a 55 mile per hour zone. Next, Agent *1483Jones watched as a passenger in the van peered through the van’s back window, stared at Agent Jones for roughly twenty to thirty seconds, and then “sank back out of sight.” Although Agent Jones drove in an unmarked vehicle, the vehicle contained a visible security cage separating the front and back seats and Agent Jones wore a uniform. Agent Jones conducted a registration check on the van based on the license plate numbers, but discovered nothing extraordinary.
His suspicion nevertheless aroused by the surrounding circumstances, Agent Jones stopped the van on Highway 185, just north of Radium Springs. Agent Jones discovered Lopez-Martinez driving the van and verified his United States citizenship. As the sedan drove past the scene, Agent Jones ■ asked Lopez-Martinez whether he was travelling with the other vehicle, to which Lopez-Martinez replied: “No we are not together. He is going to Albuquerque.” Agent Jones promptly discovered four undocumented aliens in Lopez-Martinez’s van.
On July 30, 1992, Lopez-Martinez filed a motion to suppress the evidence gathered at the stop along Highway 185, contending that Agent Jones lacked reasonable suspicion to conduct the roving border patrol stop. After the court issued extensive factual findings and denied his suppression motion, Lopez-Martinez entered a conditional guilty plea to a two-count indictment charging him with transporting illegal aliens, in violation of 8 U.S.C. § 1324(a)(1)(B)2; and aiding and abetting, in violation of 18 U.S.C. § 2. Before us is Lopez-Martinez’s timely appeal of the court’s denial of his suppression motion.
II.
In reviewing the court’s denial of a motion to suppress evidence, “we must accept the court’s factual findings unless they are clearly erroneous and must consider the evidence in the light most favorable to the government.” United States v. Maestas, 2 F.3d 1485, 1490 (10th Cir.1993). “The ultimate determination of reasonableness under the fourth amendment is, however, a conclusion of law that we review de novo.” United States v. Guillen-Cazares, 989 F.2d 380, 382 (10th Cir.1993). Insofar as Lopez-Martinez does not dispute the court’s factual findings, we proceed directly to review the court’s legal conclusion that Agent Jones’ reasonable suspicion warranted the roadside stop that gave rise to Lopez-Martinez’s guilty plea.
The Supreme Court instructs that border patrol “officers on roving patrol may stop vehicles only if they are aware of specific articulable facts, together with rational inferences from those facts, that reasonably warrant suspicion that the vehicles contain aliens who may be illegally in the country.” United States v. Brignoni-Ponce, 422 U.S. 873, 884, 95 S.Ct. 2574, 2582, 45 L.Ed.2d 607 (1975). Derived from the principles underlying Terry v. Ohio, 392 U.S. 1, 88 S.Ct. 1868, 20 L.Ed.2d 889 (1968), the “reasonable suspicion” standard for roving border patrol stops reflects the Court’s balancing of “the importance of the governmental interest at stake, the minimal intrusion of a brief stop, and the absence of practical alternatives for policing the border.” Brignoni-Ponce, 422 U.S. at 881, 95 S.Ct. at 2580.
In Brignoni-Ponce, the Court unveiled a non-exhaustive, multi-factor test that guides our inquiry into whether Agent Jones demonstrated the requisite reasonable suspicion necessary under the Fourth Amendment to stop Lopez-Martinez’s vehicle and inquire about the citizenship of his passengers, which we have summarized:
In determining whether there is reasonable suspicion to stop a car in the border area, officers may consider any number of factors, including: (1) characteristics of the area in which the vehicle is encountered; (2) the proximity of the area to the border; (3) the usual patterns of traffic on the *1484particular road; (4) the previous experience of the agent with alien traffic; (5) information about recent illegal border crossings in the area; (6) the driver’s behavior, including any obvious attempts to evade officers; (7) aspects of the vehicle, such as a station wagon with concealed compartments; and (8) the appearance that the vehicle is heavily loaded.
United States v. Monsisvais, 907 F.2d 987, 990 (10th Cir.1990) (citing Brignoni-Ponce, 422 U.S. at 884-85, 95 S.Ct. at 2582).
Agent Jones is “entitled to assess the facts in light of his experience in detecting illegal entry and smuggling,” Brignoni-Ponce, 442 U.S. at 885, 95 S.Ct. at 2582, and we must scrutinize his decision to stop Lopez-Martinez by examining the “totality of the circumstances.” United States v. Sokolow, 490 U.S. 1, 8, 109 S.Ct. 1581, 1585, 104 L.Ed.2d 1 (1989); United States v. Barbee, 968 F.2d 1026, 1028 (10th Cir.1992). Neither Brignoni-Ponce nor its progeny identify a minimum number of factors necessary to constitute reasonable suspicion or any outcome determinative criteria. Indeed, such an approach would be antithetical to a totality of the circumstances inquiry.
Insofar as our roving “border patrol stop eases are fact driven and must be considered on a case-to-case basis,” United States v. Martin, 15 F.3d 943, 950 (10th Cir.1994), Lopez-Martinez is not persuasive in his attempt to distill our numerous opinions and to isolate three factors from the Brignoni-Ponce test that always exist when we have upheld a roving border patrol stop. Compare United States v. Barbee, 968 F.2d at 1028 (upholding evening stop of vehicle, with out-of-state license plates, driving on a little-used highway commonly used by alien and drug smugglers, where passengers in back seat crouched down when headlights illuminated them), with Martin, 15 F.3d at 945 (upholding early evening stop on New Mexico’s Highway 185, despite vehicle’s in-state license plates, given extensive additional surrounding facts). Contrary to Lopez-Martinez’s contention, “[t]he concept of reasonable suspicion, like probable cause, is not ‘readily, or even usefully, reduced to a neat set of legal rules,’ ” Sokolow, 490 U.S. at 7, 109 S.Ct. at 1585 (quoting Illinois v. Gates, 462 U.S. 213, 232, 103 S.Ct. 2317, 2329, 76 L.Ed.2d 527 (1983)), and we decline his invitation to proclaim an ironclad formula.
To be sure, an officer’s specific articulable facts, when viewed in isolation, will often comport with general notions of innocent travel rather than criminal activity. Roads situated adjacent to an international border facilitate legitimate traffic. There is nothing inherently suspect about a van or station wagon utilizing such a thoroughfare. •Our task, however, is not to pigeonhole each purported fact as either consistent with innocent travel or manifestly suspicious. Rather, the reasonable suspicion calculus turns on whether the specific articulable facts, when viewed together through the lens of a reasonable law enforcement officer, justified a brief roadside detention to determine whether the vehicle contained undocumented aliens. See Brignoni-Ponce, 422 U.S. at 884-885, 95 S.Ct. at 2582; see also Terry, 392 U.S. at 22-23, 88 S.Ct. at 1880-81 (acknowledging that “a series of acts, each of them perhaps innocent in itself, but which taken together war ranted further investigation”); Sokolow, 490 U.S. at 9, 109 S.Ct. at 1586 (“Any one of these factors is not by itself proof of any illegal conduct and is quite consistent with innocent travel. But we think taken together they amount to reasonable suspicion.”); Gates, 462 U.S. at 244 n. 13, 103 S.Ct. at 2335 n. 13 (“[I]nnocent behavior frequently will provide the basis for a showing of probable cause.... In making a determination of probable cause the relevant inquiry is not whether particular conduct is ‘innocent’ or ‘guilty,’ but the degree of suspicion that attaches to particular types of noncriminal acts.”). In fact, the Supreme Court has expressly acknowledged law enforcement officers’ prerogative to perceive and articulate meaning in actions that, to the untrained observer, appear innocuous. Brown v. Texas, 443 U.S. 47, 52 & n. 2, 99 S.Ct. 2637, 2641 & n. 2, 61 L.Ed.2d 357 (1979).
III.
Mindful of these principles, we turn to examine the specific facts that Agent Jones articulated as grounds for stopping Lopez-*1485Martinez’s van. Unlike the scant record in Monsisvais that precluded us from adequately assessing the reasonableness of the border patrol agent’s stop, Monsisvais, 907 F.2d at 990-91, the record on appeal in the instant case includes extensive factual findings by the district court.
A. The Characteristics of the Area
The characteristics of the area in which Agent Jones encountered Lopez-Martinez’s vehicle and the accompanying sedan strongly support the court’s finding of reasonable suspicion. Agent Jones testified that he watched the two vehicles exit Interstate 25 from the northbound lanes at the Radium Springs exit, less than ten miles south of the Las Cruces immigration checkpoint on Interstate 25. In addition, the government presented data revealing the number of aliens apprehended within close proximity to the fixed immigration checkpoints in southern New Mexico.3 Nor does Lopez-Martinez refute the government’s evidence that, aside from a few retail establishments at which he did not stop, both the crossover road from Interstate 25 to Highway 185 and Highway 185 wind through minimally populated desert area and provide a slower, more circuitous northbound route than on Interstate 25. Compare United States v. Miranda-Enriquez, 941 F.2d 1081, 1083-84 (10th Cir.1991) (agent lacked reasonable suspicion to stop driver when he first saw him on Highway 52, which also serves as an access road for tourists visiting a nearby lake).4
B. The Proximity of the Area to the Border
Because Agent Jones encountered Lopez-Martinez less than sixty miles from the United States-Mexieo border, the proximity of the stop to the border also weighs in favor of the reasonableness of Agent Jones’ suspicion that Lopez-Martinez was en route from the border. See 8 CFR § 287.1(a)(2) (defining “reasonable distance” under 8 U.S.C. § 1357(a)(3), statute authorizing immigration officials to conduct warrantless stops, as “within 100 air miles from any external boundary of the United States”). Although we eschew any inflexible mile benchmark in considering the second Brigno-ni-Ponce factor, we find the federal regulations informative. In addition, there is a marked contrast in distances from the border between this case and U.S. v. Venzor-Castillo, 991 F.2d 634, 639 (10th Cir.1993), where we held that the agent lacked reasonable suspicion to conduct a stop 235 miles from border. See also Barbee, 968 F.2d at 1028 (upholding stop that occurred in vicinity of Truth of Consequences checkpoint, north of Las Cruces).
C.The Usual Patterns of Traffic on the Particular Road
Agent Jones’ comparisons between Lopez-Martinez’s actions and the usual patterns of traffic on the crossover road between Interstate 25 and Highway 185, and Highway 185 itself, further supports the court’s finding. Agent Jones testified that because July is green chile harvesting season, farm traffic along these routes is heavy at dawn, but nearly nonexistent at 10:00 a.m. when he encountered Lopez-Martinez’s van and the sedan. Lopez-Martinez’s evidence speaks to the daily volume of traffic along these thoroughfares, but in no way refutes Agent Jones’ testimony that the traffic is concentrated in the early morning and early afternoon, when farm laborers travel to and from work. Compare Miranda-Enriquez, 941 F.2d at 1084 (agent testified to his inability to predict the likelihood of alien smugglers travelling on highway when stop occurred).
*1486D. The Agent’s Previous Experience with Alien Traffic and Information about Recent Illegal Border Crossings
Consistent with Brignoni-Ponce, we must also accord weight to Agent Jones’ eighteen-year experience as a U.S. Border Patrol Agent and his promotion to the rank of Supervisory Border Patrol Agent. Brignoni-Ponce, 422 U.S. at 885, 95 S.Ct. at 2582. Agent Jones has worked in Southern New Mexico for approximately fourteen of his eighteen years as an agent and testified to his familiarity with alien traffic on the roads through Las Cruces and its environs. Agent Jones conceded that he had not received information about recent illegal border crossings in the area, but he explained that alien smuggling precipitously increases during the summer months due to farm employment (between 1,000 and 1,300 aliens are discovered per summer month, as opposed to between 500 and 1,000 during other months).
E. The Driver’s Behavior
Additionally probative to our evaluation of Agent Jones’ decision to conduct the stop is Lopez-Martinez’s driving behavior. Brignoni-Ponce, 422 U.S. at 885, 95 S.Ct. at 2582; United States v. Pollack, 895 F.2d 686, 690 (10th Cir.), cert. denied, 498 U.S. 985, 111 S.Ct. 520, 112 L.Ed.2d 532 (1990). Lopez-Martinez opted to exit northbound Interstate 25 yet continue to travel north on Highway 185, a well-documented means of circumventing the Las Cruces checkpoint and a less direct northbound route. See Martin, 15 F.3d at 945; see also U.S. v. Guillen-Cazares, 989 F.2d at 383 (acknowledging that agent’s discovery of a driver along a road purportedly used to avoid the Truth or Consequences checkpoint weighs in favor of reasonable suspicion); Barbee, 968 F.2d at 1029 (same).
In addition to Lopez-Martinez’s decision to exit Interstate 25 just south of the known immigration checkpoint yet continue to travel north, Lopez-Martinez appeared to be driving in tandem with a second vehicle and at a speed of 30 miles per hour on an empty road with a posted 55 mile per hour speed limit. The district court reasoned that the slow speed of both the van and the sedan was suspicious because there were no other vehicles in the area and they were driving throughout an area where the posted speed limit was significantly higher. In addition, although Agent Jones drove in an unmarked Border Patrol vehicle, he believed that the driver of the van and the driver of the sedan recognized his vehicle as a police vehicle because of the visible metal security cage separating the front and back seats as well as the fact that Agent Jones wore a uniform. Because maintaining a noticeably slow speed in the presence of a police officer may suggest nervousness, we cannot accept the dissent’s conclusion that the speed of the vehicles is “simply irrelevant when considered in the totality of the circumstances.”
Next, Agent Jones explained that aliens are often smuggled in caravans to enable a lead vehicle to determine whether a known checkpoint is open. We have held that the mere “existence of two cars, proceeding closely together and turning south on 1-25 does not evoke the same types of suspicions as other situations and maneuvers found in roving border patrol cases.” Guillen-Cazares, 989 F.2d at 383. Whereas we found nothing inherently suspicious about the two vehicles in Guillenr-Cazares entering Interstate 25 south, here Agent Jones noted that Lopez-Martinez’s van and the sedan exited Interstate 25 north just south of the Las Cruces checkpoint, drove past the few retail establishments along the way, and proceeded north on Highway 185. That the vehicles in the instant case drove close together at the same slow pace and only separated when Agent Jones passed the sedan gave farther grounds for reasonable suspicion.
F. Aspects and Appearance of the Vehicle
Although Agent Jones acknowledged that neither vehicle appeared to be heavily loaded, Barbee, 968 F.2d at 1029, Lopez-Martinez’s van could transport several passengers hidden from passersby. Pollack, 895 F.2d at 690 (suspect was driving “a large vehicle capable of hauling a large number of people”); Brignoni-Ponce, 422 U.S. at 885, 95 S.Ct. at 2582 (identifying station wagons with large compartments for fold-down seats *1487or spare tires as popular vehicles in which to transport concealed aliens). In addition to noticing four Hispanic passengers in the sedan, Id., Agent Jones watched as a passenger in the van peered out the rear window and then disappeared. Barbee, 968 F.2d at 1029 (“Also important is that the agent making the stop observed the passengers sinking down in an apparent effort to avoid detection.”).
To be sure, the fact that the passengers appeared to be Hispanic could not, by itself, create the reasonable suspicion required under the Fourth Amendment to conduct a roving border patrol stop. Brignoni-Ponce, 422 U.S. at 886-87, 95 S.Ct. at 2583. As the dissent correctly points out, the overwhelming number of Hispanics in this country are United States citizens, not illegal aliens. However, the Court in Brignoni-Ponce explained that “Mexican appearance [is] a relevant factor” when the stop occurs near the United States-Mexico border. Id.; see also United States v. Martinez-Fuerte, 428 U.S. 543, 564 n. 17, 96 S.Ct. 3074, 3085 n. 17, 49 L.Ed.2d 1116 (1976) (reaffirming that “apparent Mexican ancestry ... clearly is relevant [at a checkpoint near the United States-Mexieo border]”).
IV.
Lopez-Martinez’s attempt to isolate each of the aforementioned facts and describe how each is consistent with legitimate travel ignores the Supreme Court’s direction to examine “the whole picture” and consider whether Agent Jones had a “particularized and objective basis for suspecting [Lopez-Martinez] of criminal activity.” United States v. Cortez, 449 U.S. 411, 417-18, 101 S.Ct. 690, 695, 66 L.Ed.2d 621 (1981). Given the district court’s extensive and uncontro-verted factual findings, we conclude that the totality of the specific articulable facts, viewed in the light most favorable to the government, reasonably prompted Agent Jones to suspect that Lopez-Martinez’s van contained undocumented aliens.
Accordingly, the investigative stop did not run afoul of the Fourth Amendment and the district court’s judgment is AFFIRMED.
. 8 U.S.C. § 1324(a)(1)(B) provides in pertinent part:
Any person who ... knowing or in reckless disregard of the fact that an alien has come to, entered, or remains in the United States in violation of law, transports, or moves or attempts to transport or move such alien within the United States by means of transportation or otherwise, in furtherance of such violation of law ... shall be fined in accordance with Title 18, or imprisoned not more than five years, or both, for each alien in respect to whom any violation of this paragraph occurs.
. According to Agent Jones’ testimony, between November 1991 and November 1992, agents stationed at the Las Cruces checkpoint apprehended 970 undocumented aliens, resulting in 269 cases. Of these 269 cases, 74 arose from apprehensions at the fixed checkpoints and 195 resulted from investigative stops along roads, and in the desert, within a ten mile radius of the fixed checkpoints.
. Although the U.S. Border Patrol also operates a fixed immigration checkpoint along Highway 185, the station was closed the day Agent Jones encountered Lopez-Martinez and the previous day as well.