According to the press release,
Shortly after the car exceeds 10 mph – determined using GPS and cell tower triangulation – the mobile phone will be locked. If the driver is using the phone when Sprint Drive First engages, the call will end and the phone lock screen will appear. Anyone texting the driver will receive an automated message indicating the person they texted is driving. The message is customizable by the account holder.Sprint Drive First, powered by Location Labs, is now available on all Sprint CDMA Android-powered smartphones for $2 per month per phone and will be offered on BlackBerry devices and other operating systems in coming months. Parents get started by registering for an account at www.sprint.com/drivefirst.
A locked device displays a home screen with exit and emergency 911 buttons to override the app. Sprint Drive First can be overridden if the user is a passenger in a car, on a bus or train, but the parent or account holder can choose to receive notifications when the service is overridden.
Parents have a choice of programming up to five phone numbers to ring through when the phone is locked as well as allowing functionality of three apps, such as navigation, music or weather.
When the application no longer detects movement it unlocks and full device functionality resumes. Sprint Drive First takes into account stop-and-go traffic, so the driver needs to be sitting idle for a few minutes before it will unlock.