Mark IV, the maker of the electronic toll-collection system E-ZPass, said recently the use of a cellphone near its collection tags could cause the tag's batteries to go bad. According to the company, the batteries, designed to last 10 years, are now going bad after just one year because some cell phones operate on the same frequency as the tag, causing them to operate for longer periods of time. All tags shipped from the Toronto-area company's factory now block cellular signals, but some older models may still be susceptible to the problem, the company says.