The heaviest users of AT&T’s unlimited wireless data service will have connection speeds “throttled” once they reach a certain monthly bandwidth threshold, pursuant to a new policy announced by AT&T last Friday. AT&T’s decision to slow the transmission speeds of high bandwidth users will impact long-time AT&T wireless broadband subscribers who signed onto one of AT&T’s unlimited data plans before the company terminated its unlimited plans in favor of tiered data offerings in June 2010. The new policy, which is scheduled to go into effect on October 1, will not affect the 15 million AT&T smart phone customers who have since signed tiered data contracts that impose usage caps. Although AT&T did not specify how much data a subscriber must consume before his or her monthly usage is throttled, a company spokesman said the policy change would affect the top five percent of AT&T customers who consume twelve times as much data as all other users combined. Statistics published in a recent Consumer Reports survey show that the average AT&T smart phone user consumes 360 megabytes of data per month. As such, subscribers on unlimited data plans who consume in excess of 4 gigabytes per month would be subject, in theory, to throttling. Customers approaching usage thresholds will be warned before their traffic is throttled, and normal speeds will be restored at the start of the next billing cycle. The policy change leaves Sprint Nextel as the only major national carrier that does not cap usage or impose speed limits on its heaviest data users. While emphasizing that the policy “will never impact the vast majority of our customers and is designed to create a better service experience for all,” AT&T stressed “it will not solve our spectrum shortage and network capacity issues,” adding: “nothing short of completing the T-Mobile merger will provide additional spectrum capacity to address these near-term challenges.” Criticizing AT&T’s move as “simply the latest example of Internet rationing,” Public Knowledge legal director Harold Feld quipped: “the $39 billion AT&T will spend for T Mobile would go a long way to helping improve its network.”