Startup Idea : Car Problem Notifier

Let a car owner know if you have noticed a problem with their car when travelling behind it in traffic. Mobile app, voice activated to ensure no handling of mobile whilst driving. Register licence plate details with the app (plate number, state/country) and other details like the associated mobile number. When a problem is noticed, activate app, state licence plate details and problem noticed (ie. left brake light not working). If the car mentioned is also registered the mobile associated with the car receives a message/alert. Could incorporate motor part distributors advertising, or be a project of the car insurance industry as it should save on some claims. Worldwide application.