Texting while driving: are apps enough to prevent accidents?

Have a habit of texting while driving? It's a dangerous one. While there are no solid statistics on how often cell phones cause car accidents, a study from Virginia Tech Transportation Institute, which monitored drivers for more than a year using in-car cameras, showed that cell phones were the most common driver distraction. It also found that the risk of a crash or near crash was 23.2 times more likely when texting. Another study by the RAC Foundation found that reaction times slowed by 35 percent when subjects were writing or reading text messages. If you're looking to stop texting while driving - or you want to keep your teen from doing so, guess what, there's an app for that. In fact, there are several apps, such as DriveSafe.ly, dedicated to preventing this behavior. (You can also sign Oprah's No Phone Zone Pledge.)

Here's a quick look at some of the text-blocking apps available. Most use your phone's GPS chip to detect motion and thus block service while driving, and just about all of these apps work only with smartphones and require a monthly fee.

Most expensive: TXTBlocker

• $24.99 up front, then $9.99/month
• Compatible with Blackberry smartphones
• TXTBlocker works like parental control software in that you can set time and location restrictions for texting or other cell phone use. You can also create a safe list of numbers like 911 that can always be dialed.

Most restrictive: IZUP

• $5 a month or $50 a year
• Compatible with select BlackBerry, Android, LG and Samsung phones
• IZUP disables your phone (almost) completely. (David Pogue calls it a Nazi in his roundup of text-blocking apps.) All you can do when the car is in motion is dial 911 or any of three pre-approved numbers.

Almost as distracting as texting while driving: ZoomSafer

• $2.99 a month or $25 one-time fee
• Compatible with most BlackBerry smartphones and some Windows Mobile smartphones
• ZoomSafer can be automatically or manually enabled to lock your cellphone when driving. When enabled, the service will sends auto-replies to unanswered calls, emails, and texts. You can set it up to notify family and even social networks when user starts and stops driving. If you upgrade to Voicemate ($3.99 a month or $40/year) you can have your text and email messages read aloud and use voice commands to respond.

Almost as distracting as ZoomSafer: DriveSafe.ly

• Free; $3.99/mo or $20 per year
• BlackBerry, Android, iPhone, Windows Mobile
• DriveSafe.ly uses text-to-speech to read incoming messages and sends a customizable auto-reply letting the sender know that you're driving and can't respond. (BerryReview.com has a good review of DriveSafe.ly.)

Best bets for parents of teens, provided your teen has an Android smartphone: Textecution

• $29.99 one-time fee
• Compatible with Android smartphones
• Textecution uses your phone's GPS to detect if you're moving faster than 10 mph, at which point it disables texting. If you're a passenger or riding a bus or train, you can ask for permission to text from the account administrator, who can text "allow" to override the software.

Best bets for parents of teens, provided your teen has an Android or BlackBerry smartphone: CellSafety

• $9.99 per month
• Compatible with BlackBerry and Android smartphones
• CellSafety disables your cell phone while you're driving and can be set up to block text messaging while in certain "zones" such as school. Offers a wealth of additional parental controls and GPS tracking.

As you can tell, no single app is a complete solution. Compatibility issues aside, savvy teens will be able to find workarounds and some of these apps seem rather distracting themselves. The best solution is to reinforce the risks of driving while texting or talking on the phone - and to lead by example. It's also worth looking into the parental controls offered by your wireless carrier, which will offer more for your money.