Does the fact that a vehicle is in a notorious narcotics and alien smuggling region need to be considered as a factor in determining whether to stop the vehicle?

It is true that an officer may consider the fact that a particular region is known for transportation of narcotics and aliens in determining whether there is reasonable suspicion to stop a vehicle. See, e.g., United States v. Sutton, 794 F.2d 1415, 1425-27 (9th Cir.1986). But, in the absence of other, substantially more probative and particularized considerations, an officer cannot stop a vehicle primarily because the vehicle is in a notorious narcotics or alien smuggling region.