Operators are testing their control center in preparation for the opening of the 495 Express Lanes this fall. (Robert Thomson/The Washington Post)

When Virginia’s 495 Express Lanes open later this fall, they’ll open in the middle of the night on a weekend. Commuters will have their first experience with them during a Monday morning rush.

There won’t be any free test drive period, as there was when Maryland’s Intercounty Connector opened, and state officials wanted travelers to get acquainted with the brand new highway.

Transurban, the operator of Virginia’s new toll lanes, figures drivers already know where the Capital Beltway is. They’re not marketing a new road. They’re marketing a new experience driving that road.

“We’re opening a new Interstate highway inside an Interstate highway,” Jennifer Aument, a Transurban vice president, said Wednesday during a briefing about the new lanes. On the inside part, the trip should be quicker and more reliable for those willing to pay a toll or take a bus or get into a carpool.

There’s still no exact date on which we’ll be able to record our first impressions of that experience, but when it comes, Transurban doesn’t want to leave us wondering what all the fuss was about. The operators hope they’ll be welcoming us to more than some new asphalt that could turn out to be just as crowded as the old asphalt.

In fact, most of the lane and interchange construction is done, and the focus is on  building up and testing the lane-management system. For weeks, Beltway drivers have watched test vehicles driving in the new lanes to measure the effectiveness of the traffic monitoring equipment.

Aument noted that unlike some of our other big road projects of the past decade — the Wilson Bridge, the Springfield Interchange and the Intercounty Connector — there are no phases to the opening of the 495 Express Lanes. The entire project must be ready to go on Day One. (First impressions are so important.)

Transurban’s briefing Wednesday continued a year-long education and marketing campaign, designed to get its potential customers as ready for the opening as officials hope their lane system will be.

For example, they are strongly encouraging commuters to get their E-ZPasses early, if they don’t have a transponder already. All users of the new lanes will need E-ZPasses, either the standard kind or the new E-ZPass Flex, designed for those who want to carpool and get a free trip.

One update on that from Aument: Maryland’s E-ZPass program has now begun offering the Flex transponder for sale. The Flex units, which can switch between the regular travel mode and the carpool mode, have been available through the Virginia program for several months. But drivers who live in, say, the Rockville area and commute to Tysons with at least two other people in the car might find it more convenient to get the Flex through the Maryland program. They should note that the financial details of the Maryland program are different from that in Virginia.

Maryland offers three options for buying the Flex: Go to the Maryland program’s Web site at www.ezpassmd.com, call 888-321-6824 or stop by any E-ZPass Maryland Center.