Comcast will soon kick the tires on an “Unlimited Data Option” in parts of Florida that lets high-speed Internet subs upload data and stream all the video they want for an additional $30 per month.

The trial, spotted by DSL Reports and posted by Comcast here, is an enrollment option that applies only to Comcast subs in Fort Lauderdale, the Keys and Miami, Florida. Comcast will begin testing the new policy there on October 1, and is notifying customers in the area about a month in advance, a Comcast spokesman said.

“The Unlimited Data Option costs the current additional fee of $30 per calendar month, regardless of actual data usage. The 300 GB plan will not apply to customers who enroll in the Unlimited Data Option,” Comcast explains in the FAQ.

Comcast has been testing usage-based Internet policies in several markets, including Atlanta, Miami, Maine, and Nashville, that fits customers with a soft monthly usage cap of 300 Gigabytes per month. Users who exceed that threshold are subject to a $10 fee for each additional bucket of 50 GB. Comcast has also been testing a more variable usage-based policy in Tucson, Ariz., that adjusts the monthly consumption ceiling based on the speed of the customer’s data tier. Comcast is also testing a “Flexible-Data Option” that’s tailored for light Internet users on the MSO’s 3 Mbps Economy Plus tier. That opt-in trial caps usage at 5 GB per month before customers are subjected to per-gigabyte fees. Customers who do not exceed the monthly 5 GB ceiling receive a $5 credit, but will be charged an additional $1 per GB consumed beyond the 5 GB threshold.

By way of example, customers on the Unlimited Data Option who consume 530 GB in a given month, will be charged $30 extra. Those on the other usage-based policy would be charged $50 for the additional 250 GB (five blocks of additional 50 GB) provided on top of the 300 GB plan. "Note that customers enrolled in the Unlimited Data Option who use less than 300 GB in a given month will still be charged $30 for that month," Comcast explained.

The Unlimited Data Option “is a consumer trial and may be discontinued at any time,” the MSO noted, adding that data usage plans currently do not apply to customers on its fiber-based Extreme 505 and Gigabit Pro (2 Gbps) plans, or business Internet subs on “Bulk Internet agreements.”

Comcast’s original 250-GB fixed cap policy was introduced in October 2008, but announced in May 2012 that it would begin to trial “improved data usage management approaches” while suspending enforcement of the old policy.

Update: With respect to the new unlimited data policy it’s testing in Florida, Comcast, a spokesman said, found in a customer survey with some heavy data users that 60% “expressed interest in an unlimited data plan option at the predictable, flat price of around $30 a month.”

Comcast, he added, found that about 10% of its customers consume almost half of all the data on the operator’s network, “so these trials are based on principles of flexibility and fairness. They’re flexible, because we got rid of a static cap and they’re fair because we have trials at both ends of the spectrum,” he added noting that heavy data users can pay more to use more while light users on Comcast’s Economy Plus plan can try the aforementioned Flexible Data Plan.