Sen. Tom Udall (D-N.M.) introduced a piece of legislation yesterday aimed at reducing bill shock, the unexpectedly high bills sometimes received by wireless subscribers.

The legislation marks Udall's second attempt to get the bill shock measure through the Senate.

The Cell Phone Bill Shock Act of 2011 would require wireless operators to notify their customers by SMS or e-mail when they've used 80 percent of their monthly limit of voice minutes, text messages or data usage.

The bill would also require wireless providers to obtain a customer's consent before charging for services in excess of their monthly limit of voice, text or data usage.

"Sending an automatic text or e-mail notification to a person's phone is a simple, cost-effective solution that should not place a burden on cell phone companies and will go a long way toward reducing the pain of bill shock by customers," Sen. Udall said.

Udall, a member of the Senate Commerce Committee, introduced a similar bill last September, but the measure died in committee.

His current bill currently does not have any co-sponsors, and its success is unclear. The bill was read twice yesterday before being referred to the Senate Commerce Committee, which failed to move on Sen. Udall's bill last fall.

CTIA has lobbied against laws and regulations on bill shock and came out against Sen. Udall's latest proposal.

CTIA spokeswoman Amy Storey argued that government measures to help reduce unexpectedly high wireless bills were not necessary since wireless operators already provide subscribers with tools to manage their accounts.

"Legislation that attempts to standardize these practices will also have the effect of freezing these developments in place and limiting innovation," Storey said. "That doesn't help consumers."

The bill shock legislation was prompted by an FCC report on the matter last spring and several high-profile instances of large, unexpected charges on subscribers wireless bills, including the case of a Navy ROTC midshipman who mistakenly left his smartphone's roaming function turned on while he was abroad and returned home with a bill for almost $1,300.

A survey from the FCC last spring found that one in six U.S. wireless subscribers have been hit by unexpectedly high wireless bills. Of those, 84 percent said their wireless carrier did not contact them when they were about to exceed their limits, the FCC reported.

The agency used the data to support its bill shock proposal last fall. The FCC has yet to move on the measure.

The proposals from Sen. Udall and the FCC are similar to measures taken by the European Union, which requires wireless phone companies to provide notifications to their customers when they have reached 80 percent of their monthly data roaming services.