In the early days of in-car cameras, getting the signal from the car to the home viewer's television was a bit tricky. The in-car camera would broadcast images to a helicopter hovering over the track, which would return the signal to a trailer owned by the broadcast company.
The process is similar today, but it takes a lot less fuel. The helicopter has been replaced by receivers placed along the top of the track's bleachers. The in-car cameras send out signals that are picked up all along the route by the receivers. These receivers send the signal to a trailer, just like the helicopter did, where it's processed for television. The finished signal is then sent to the network carrying the broadcast.
The signal gets from the network to our TV sets like everything else does, via cable, satellite, Internet connection, or over the air and into a set of rabbit ears perched atop the television. The in-car cameras have created a sense of intimacy for at-home NASCAR fans. They feel even more connected to their favorite drivers when they can see that driver pump his or her fist as he or she cross the finish line, or when they can hear their favorite driver communicate with the crew chief about his or her car's performance on the track.
Companies like the satellite television provider DirecTV have signed deals with NASCAR to take advantage of this relationship between fans, drivers and the in-car cameras. DirecTV, for example, offers a "NASCAR HotPass" package with high-definition images from in-car cameras and dedicated audio channels for selected drivers.
As technology advances and cameras are able to deliver crisper images from tinier equipment, you can bet NASCAR will take advantage. Infrared engine cam? In-helmet cam? Anything is possible -- as long as NASCAR can find someone to sponsor it.