When a wireless communications device is traveling a speed exceeding a first predetermined threshold but less than a second predetermined threshold, the device is presumed traveling in a motor vehicle. In order to inhibit operation of the wireless communication device when traveling, access to certain device functions or applications such as e-mail, text messaging, etc. are limited by requiring the user of the device to respond correctly to a randomly generated visual challenge, such as, for example, a CAPTCHA (in which a user is prompted to recognize the characters in a visually distorted string of text). This visual challenge presents a sufficient obstacle that the user will be less likely to use the wireless communications device for e-mailing or texting while operating a motor vehicle.