Zipcar and Flexcar, D.C.’s two most popular car-sharing companies, announced they are merging Wednesday. Emails to customers of both companies directed them to an announcement on Zipcar’s website.

“The combined company will provide our members with increased benefits and improve our ability to expand into new markets,” said Zipcar CEO Scott Griffith in the statement.

The new company will operate under the Zipcar name, and while the pricing plans are still being hammered out, they will use FlexcarZipcar’s higher maximum 180 free miles per day, and will charge an hourly rate of around $10-$11, explained Mark Norman, former Flexcar CEO and now president and COO of Zipcar. Insurance limits will also be increased to $300,000 per accident, as opposed to state minimums.

In a conference call with the press on Wednesday, Griffith and Norman addressed a number of issues related to how this will affect the D.C. area specifically. D.C. and San Francisco are the only two markets in which Zipcar and Flexcar compete heavily.

Here’s what you need to know: Between now and the end of January, Flexcar customers will receive new Zipcards in the mail. There will be a transition period where some Flexcars will still be on the road before being converted into Zipcars, and will still have to be reserved on the Flexcar site. As Flexcars are outfitted with Zipcar technology, they will be transferred to the Zipcar web site, until eventually all customers will use Zipcar exclusively.

As for how many cars that will mean for the D.C. area, Griffith estimates that the company holds “more than 600 cars [in Greater Washington] together going forward.” He also said, however, that Zipcar is always measuring supply and demand and moving cars around in the natural course of doing business, so it’s possible there could be some change in that number after the initial transition allows the company to discover whether there are redundant vehicles in specific locations in the D.C. market.

The Washington Business Journal has more.