This is also one of my hobby projects. I started to work on it with my teammates during a hackathon. With a single dashcam feed it can:
detect and recognize objects, track and identify them
forecast their future positions up to a second
predict 3D distances from 2D images
measure the risk of crashing
It can be used to alert the driver before collisions via predicting other objects future position or detecting objects outside of the driver sight. Another application can monitor the drivers driving behavior and give feedbacks. This would be useful for car sharing services where companies could set prices based on how safely the driver is driving. etc.