Green Car Congress: New Mobile Life Guard app monitors driving behavior and issues verbal alerts:

“Ram Dantu, a professor of computer science and engineering at the University of North Texas, is developing ‘Mobile Life Guard’—a mobile app that will enable smart phones to detect weather, road conditions and bad driving using existing sensors in the devices.
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The app then issues a verbal alert, such as ‘Sudden accelerate’; ‘Hard braking’; ‘vehicle wandering detected’; ‘tailgating detected’; ‘lane hopping detected’; ‘bad right (or left) lane change’; or ‘left (or right) swerve detected’, among other things. It also will warn you not to talk or text.”

JW writes:

I’ve suggested to a number of people that smart phones could detect when a car is driven in congested conditions. This article seems to confirm that.
The reason this is important is that for road pricing you want to internalize the negative externality of congestion. Time of day pricing is not as effective as detecting when a vehicle is actually in congestion. Time of day pricing actually charges drivers for externalities they are not imposing on others. The smart phone app could also address privacy issues because it would be unnecessary to determine where the vehicle is to charge congestion pricing rates. The congestion charge could be allocated statistically based on congestion observed through traffic management centers or regional transportation models.