It seems like a nice project. I have done something similar before. As I saw your project, I double-check my reports and files to check the conditions of that project.
First you need to clarify some points about the definition of the project and be more specific about it.
Considering the assumption of everyone has a smartphone with WiFi/Bluetooth on, You want to count people, or measure the congestion, or count the traffic? or you want to log people, or track people? Any specification of the project in this regard can significantly affect the solution.
And how vast is the area you want to collect these info form? Is it in the range of an access point or a network of access points is needed to collect the packets/info?
Please feel free to contact me if you have any questions in this regard and want to discuss the details. I would be happy to help.
Regards
Mehdi