To a child, a road trip is the equivalent of being locked in a small room for hours, chained to a chair, with no one to talk to except for a brother or sister, inevitably the most annoying person on earth. The adults who forget this are the ones who are surprised at all the fighting in the backseat.

Not to worry, corporate America is here to help parents with these little problems. After all, everyone knows the best tranquilizer for bored children: television.

Hasbro’s Video Now and Mattel’s Juice Box are both handheld video players designed for ages 6 and up that are reasonably priced – about $70 – and can take a beating from careless children. Mattel’s 3-inch screen is bigger than Hasbro’s 2.25-inch screen, but both produce adequate color images with adequate sound. Both are designed to reduce the number of moving parts, making them harder still to destroy, and both include large buttons and very simple interfaces.

Hasbro’s Video Now Jr., designed for 3- to 6-year-olds, has truly enormous buttons for “little hands on the go,” as its promotional material promises. It runs on standard AA batteries and tends to get between five and 10 hours of battery life.

That’s the good news. Unfortunately, the Hasbro and Mattel players are designed to only read the companies’ proprietary videos. The DVD library that so many children have accumulated through birthdays and holidays is now dead weight as far as these video players are concerned.

Furthermore, Hasbro and Mattel seem to have opted for the Gillette model of selling the razors cheap and the blades dear – or in this case, offering inexpensive players but overcharging for the videos. Hasbro’s Video Now has 56 titles available that range from Peanuts cartoons to contemporary TV hits such as “Jimmy Neutron” and “Dinosaur Planet.” Each disc is 25 minutes long and costs $9.99. Mattel’s Juice Box has even fewer titles – just 25, including “Dexter’s Laboratory” and the “Power Puff Girls.” The 30-minute chips cost $9.99 and a full-length feature (90 minutes) costs $24. Nearly all the titles are child oriented, though for some reason Hasbro has the decidedly adolescent-oriented “Fear Factor” on its list.

For my money, Nintendo’s Game Boy Advance is the best in portable entertainment. It has long battery life and a huge game library, and its 2.9-inch screen is almost as big as the Juice Box. And Game Boys can now be used for watching movies as well. This year the Chinese First Sing Company produced a device called the GBA Movie Player ($29.99), which converts DVDs into Game Boy format. Users must have a Compact Flash memory reader (about $25) to use the GBA Movie Player, and the formatting process requires several steps, but the payoff is worth it: DVDs, eBooks, and MP3s magically become Game Boy compatible, and squabbling children magically become quiet passengers.