There are two issues that affect in-car signal loss. Either you are driving through a dead zone - an area where the signal is weakened or nonexistent - or your car might actually be blocking part of the signal.

This signal loss can be a problem, because one of the many reasons new users purchase a cell phone is for security. And according to the New York State Department of Motor Vehicles, nearly half of all users have used their cell phones to report car trouble, medical emergencies, crimes and drunk or reckless drivers. These well-timed calls have saved lives and prevented accidents.

"A weak car signal is problematic for people who rely on their cell phones for safety. In some cases, you may be driving along and get too weak of a signal to use your phone," says Lloyd R. Meese, chief executive officer of Wi-Ex, a company that uses a patent-pending technology to increase signal strength inside the car.

"Although safety is a good reason to have a cell phone in the car, the cell phone has expanded beyond voice applications for many drivers and commuters. They need continued signal to catch up on returning phone calls, check Web sites for travel information or check on the location of their child's soccer match."

New technology that amplifies and improves the signal is available in the form of a U.S.-manufactured signal booster called zBoost. The zBoost wireless unit, when installed in the car via an adaptor plugged into the cigarette lighter, provides more miles of uninterrupted signal, decreases dropped or missed calls and extends the battery life of the phone. It works with major phones and carriers and supports simultaneous use.

Wi-Ex's zBoost is available at premier consumer electronic stores such as Radio Shack or Fry's and online at Tiger Direct or Solid Signal.