Techniques are described for enhancing security, customization, and/or group interaction of users in vehicles. For instance, a mobile device of an owner of a vehicle may be registered in a manner that allows the mobile device to control operation of the vehicle and authorize guest user operation of the vehicle. In addition, the vehicle may be adapted to receive preferred vehicle settings from mobile devices positioned in the vehicle, such as a mobile device of a guest user, and customize the vehicle settings based on the retrieved preferences. Further, the vehicle may be equipped to communicate with in-pavement vehicle detection systems and enable interaction in an ad hoc group with other vehicles positioned to connect to the in-pavement vehicle detection systems.