If you need to reply on an app to avoid being hit by a car, you probably shouldn't be on the damn phone anyway! Duh, problem solved.
"The app relies on machine-learning and image-recognition algorithms to identify the fronts and backs of vehicles, and takes into account varying light conditions, phone tilt, and blur. When WalkSafe detects a car approaching at 30 miles per hour or faster, it vibrates the phone and makes a sound to alert the distracted user."
