and EDIG's Nunchi is the tech driving it (no pun).

The new Sidekick 4G also comes equipped with DriveSmartTM from T-Mobile, a first-of-its kind service from a U.S. carrier, that helps prevent distracted driving. When initiated, DriveSmart Basic provides automatic incoming call and message management, sending a customizable note to callers and senders, letting them know that the recipient is driving and will respond when it's safe. DriveSmart Plus offers the same functionality, with the added capability to automatically activate when the handset is in a moving vehicle, as well as advanced parental controls for enhanced peace of mind when teen drivers are behind the wheel.