A method for authorizing purchases by an owner of an account previously established with a bank where the owner wants to purchase an item from a merchant. The system includes a human machine interface located in a vehicle for allowing an occupant to interface with the infotainment device. For generating the braking force, the moving brake friction member moves towards the stationary brake friction member and fits against it at a contact abscissa or a contact surface. Various embodiments of the invention are described and in a preferred arrangement the first and second pressure measuring means are venturi flowmeters.