According to two American studies, talking on the mobile phone while traveling is dangerous for both drivers and pedestrians.

Led by Rutgers University researchers in Newark, New Jersey, the studies have shown that whether travelers use the phone while driving or while walking, it is increasing the deaths of pedestrians as well as those of drivers and passengers.

Economics Professor Peter D. Loeb, lead author of the studies, has recommended crackdowns on cell use by both pedestrians and drivers.

He says that the new studies relate the impact of cell phones on accident fatalities to the number of cell phones in use, showing that the current increase in deaths attributed to cell phone use follows a period when cell phones actually helped to reduce pedestrian and traffic fatalities.

The researcher said that that reduction in fatalities disappeared after the numbers of phones in use reached a "critical mass" of 100 million.

While conducting the studies, the researchers focused on cell phone use and motor vehicle accidents from 1975 through 2002, and factored in a number of variables, including vehicle speed, alcohol consumption, seat belt use, and miles driven.

They found the cell phone-fatality correlation to be true even when weighing in factors like speed, alcohol consumption, and seat belt use.

Loeb says that, at the current time, cell phone use has a "significant adverse effect on pedestrian safety" and that "cell phones and their usage above a critical threshold adds to motor vehicle fatalities."