Nowadays, free Wifi hotspot is common in daily life, you can connect a free wifi in airport, restaurant, supermarket, library etc. Some countries already build wifi city, it allows you to connect free wifi in every conrner of this city. Then people who use GSM/GPS tracker for their cars ask why don’t use GPS tracker with wifi function?

P: GPS tracker uses GSM network to transfer data and send command, WIFI of course can do that. What is more,  WIFI is faster and more stable than GSM, you don’t have to worry about the issue caused by unstable GSM network.

C: It requires WIFI network with a range of coverage. However, you can not make sure everywhere support wifi. When the car enter suburb areas, no wifi at all, you'll lose the tracking at once.  Even if the wifi city, there are still some areas without WIFI network.

So we can do the tracking with wifi, and if you need real time tracking, that will be difficult thing indeed. But that does not mean wifi is useless in GPS tracking industry, you still can use it in different application.

1) wifi GPS tracker with data logging

Store location info to the TF card, and upload to the tracking system when the car enter the area with wifi. No need SIM card at all, no extra cost. 

2) Real time tracking by mobile hotspots

If you need real time tracking with wifi indeed, you may try this new solution from oner. 

Add mobile hotspot, GPS tracker connects these mobile hotspots to do the real time tracking.  The GSM capability of mobile is better than GPS trackers, you may get better tracking.  In this case, you need driver to set up hotspot and add it