However, this fall a new system from Sirius Satellite Radio looks to overcome even this limitation. Called Sirius Backseat TV, the service offers live in-car television in the form of three channels aimed at families. The bundle of the Cartoon Network, Disney Channel and Nickelodeon will first be available in the 2008 Dodge Caravan and Chrysler Town & Country minivans and has one major advantage over the competition: Not only does it work while in motion, it doesn’t lose the signal when you cut across town.  Sirius relies on satellites to transmit its lineup of 75-plus channels of music and talk radio. The position of its satellites makes it easier to pick up a signal than with DirecTV, and in built-up urban environments where obstructions prevail, the company uses terrestrial repeaters to beam its stations to vehicles. So because the new video stations travel the same route as the audio channels to car receivers, customers should receive video wherever they receive satellite radio service.  During a recent Manhattan trip as a passenger in a Jeep Commander with the new Sirius system, I watched “Blue’s Clues” and “The Backyardigans” without interruption. No matter where we turned, the Backseat TV maintained reception. On the Commander’s ceiling-mounted seven-inch L.C.D. screen, picture quality was acceptable, and certainly good enough for cartoon viewing. However, in videos featuring a lot of high-speed motion, like “The Powerpuff Girls,” the images were a bit blurry and had some blocky distortion, a result of the extensive digital compression of the signal. So while it’s fine for children’s programming, I wouldn’t want to try watching a football game on it.  “You’re not going to get an HD quality signal, but we believe it’s very good quality,” said Doug Wilsterman, a senior vice president at Sirius. And it is live television, with some custom children’s programming added to fill in the evening hours of the Cartoon Network and Nickelodeon when the cable and satellite channels usually offer fare aimed at older audiences.  Backseat TV will be exclusive to the Chrysler Group for the 2008 model year. In addition to the minivans, vehicles like the Dodge Magnum and Jeep Grand Cherokee will offer it as an option later this year.  Chrysler will charge $470 for Backseat TV, which includes a one-year subscription to the service, but buyers first have to spring for the rear-seat entertainment system, which is about $1,400 on average, plus another $195 for the Sirius radio option. That puts the initial total cost of the system for most shoppers at more than $2,000. After the first-year subscription runs out, the monthly charge is $19.95 ($12.95 for the necessary radio subscription and another $7 a month for the video channels).  Although the system doesn’t require a saucer-shaped antenna like the TracVision, the Sirius service requires some technical and equipment changes, Mr. Wilsterman said. Cars must be outfitted with two Sirius antennas, which look like small computer mice stuck on the roof, and a new receiver to decode the digitally compressed video stream.  Mr. Wilsterman said Sirius hoped add-on TV tuner hardware packages would be available by Christmas for those who wanted to add the feature to their existing vehicles. But no specific products have been announced.  He declined to comment on whether it would eventually offer additional channels. Of course, even having hundreds of live television channels in the back seat may not remedy every bout of ennui. Just as at home, no matter how many options they have, children will doubtless still complain that there’s nothing to watch.  A version of this article appears in print on , on Page 122 of the New York edition with the headline: Tuning in ‘24’ While Heading Down the Highway. Order Reprints| Today's Paper|Subscribe
Endless viewings of “Shrek 2” or “Over the Hedge” can generate boredom in the back seat, too, which is why the next big thing for in-car entertainment may be live TV.