In some embodiments, a processor-implemented method for disabling at least one text application on a mobile device may comprise: processing an image captured in a vehicle by a mobile device to identify a seat belt in the image; determining a slope of the seat belt relative to a horizon, wherein the horizon is determined using information pertaining to a position and an orientation of the mobile device relative to a frame of reference at a time when the image was captured; determining a speed of the mobile device; and disabling at least one text application on a mobile device based, on the slope of the seat belt and the speed of the mobile device.