I get how the problem is similar to the Yelp example, but for the scale at which we're working I don't think creating the Quad-Tree is necessary. Especially because the driver location information is only relevant "right now". There's no need to persist it for future reference. Wouldn't if be sufficient to only store the driver location in-memory using something like memcached? Even if the memcached server went down you could have replicas of it, and only the most recent location of the driver that would be put in memcached would be relevant.