(Kevork Djansezian/AP) Many parents would love to be able to give their teenagers a cellphone that couldn't be used while driving. Now some inventors say they have come up with ways to make that possible, but they appear to be relying on wishful thinking.

One product to hit the market, $10-US-a-month software by Dallas-based WQN Inc., can disable a cellphone while its owner is driving. It uses GPS technology, which can tell how fast a person is travelling. But it can't know whether the person is driving — and therefore it can needlessly lock a phone. WQN, which sells cellphone and internet security software under the name WebSafety, says it signed up about 50 customers for its first month of service.

Aegis Mobility, a Canadian software company, plans to release a similar Global Positioning System-based product this fall, known as DriveAssistT. Aegis is in talks with big U.S. wireless phone carriers, which would have to support the software and charge families a fee of probably $10 to $20 a month, said David Teater, the company's vice-president.

The DriveAssistT system will disable a phone at driving speeds and send a message to callers or texters saying the person they are trying to reach is too busy driving. But because that person could be a non-driving passenger, the approach is a blunt tool.

Education vs. technology

Other product concepts that don't involve GPS systems have their own flaws. As a result, Parry Aftab, who advises families on technology and safety, suggests worried parents find another way to stop their kids from calling or texting while driving. Parents are better off taking away a child's cellphone if it is used improperly, she said.

"More and more, we see any solution is, in large part, education and awareness, parents getting involved," said Aftab, executive director of WiredSafety.org. Driving and cellphone use can be a bad combination, "but so is putting on makeup and eating a three-course meal," Aftab said. "I wish technology providers would look hard at the problems before coming up with a knee-jerk solution."

Concerns are mounting that driving while gabbing or text-messaging on a cellphone, even if it is not handheld, is unacceptably dangerous. The U.S. National Safety Council said this month that there should be a total ban on cellphone use while driving, citing the higher risk of accidents and deaths.

B. Michael Adler, chief executive of WQN, said his 18-year-old son came to mind as he was developing the company's software to disable a cellphone while driving.

"He's texting messages with two hands and driving with his legs," Adler said. "You flip him the keys to the family car, you might as well be flipping him a six-pack of beer."

WQN's surveillance service promises more than just disabling the phone in cars. It can monitor a person's whereabouts, notifying parents by text messaging when their children step out of designated zones or return home. It also can turn off a cellphone at school, preventing cheating by text messaging during classroom tests, based on a reading of the school's location.

The question parents would have to ask themselves is whether they'd want to prohibit their children's activities this way. That kid you're trying to control might not be driving, but rather sitting on a train or a city bus or in the passenger seat of a buddy's car.

Human nature

Michael Hensley has thought about this very dilemma. The 52-year-old manager for a defence contractor worries that his 23-year-old daughter is a "thumb Olympian" inclined to send text messages while driving.

But he doesn't expect technology to provide an answer. Savvy kids "will always find a way to defeat" a technological product, Hensley said. "It's human nature to defeat the system."

Instead, Hensley said, he's tried to educate his daughter about the dangers of mixing phones with driving.

The inventors of the GPS-based software systems acknowledge their systems aren't perfect for disabling cellphones and are hard at work on improvements. Meanwhile, a separate, hardware-based solution appears to have its own flaws.

A pair of inventors affiliated with the University of Utah have developed a prototype of a key fob device that communicates with a cellphone over Bluetooth wireless signals. The key fob wraps around an ignition key; when the key is flipped or slid open, the device disables the cellphone paired with it.

This turns out to be easy to beat. A kid could remove or run down the key fob's batteries, or duplicate the key — without the fob. So the Utah inventors, Wally Curry and Xuesong Zhou, have dropped their original concept for something different.

Zhou considered transforming the key fob into a device that prevents nothing. Instead, it would let a driver hit a "quit" button and talk or text at will, but with a consequence: parents get notified by text messaging, and a monthly "driving score" could go to an insurer, which might jack up the teenager's premiums for bad driving.

Even that, Zhou acknowledged, wouldn't solve the tampering problem. So in his latest brainstorming he produced an elaborate scheme: Parents should estimate how many hours a child drives each month and report that to a website. If the key fob system reported the teenager appears to be driving substantially less than the prescribed time, it might indicate he's defeating the system, and the website could send a report to the parent.

For now, though, the key fob is going back to the drawing board.