Functioning as a digital safety belt, !important is a mobile app that communicates the user's location to nearby connected vehicles. The technology can immediately alert drivers and even trigger vehicles' brakes automatically to prevent a collision with an approaching person, bicyclist, or motorcyclist. While existing vehicle-based sensors such as cameras, radars, sonars, and lidars may prevent up to 35% of pedestrian fatalities (INRETS Report No. 256), the remaining 65% are left unsolved by current technologies. !important is the first pedestrian-based technology that works in all contexts. It could save a million lives over the next decade. The !important app is currently available for free on the iPhone and Android App stores.