Many of the signs on the Capital Beltway’s new express lanes have been activated in advance of the Nov. 17 opening. (Robert Thomson – The Washington Post)

I’ve been looking at maps of the 495 Express Lanes since the entrance and exit ramps were nothing more than piles of dirt, and thought I was quite familiar with the layout.

Now, I’ve had my first experience riding along the lanes, sitting in the passenger seat of a car, and my advice to potential users is this: Even if you think you know the Capital Beltway and are familiar with the high-occupancy toll concept, take some time to review how you would get on and off the express lanes before using them.

Jennifer Aument, a vice president with Transurban, the company that will operate the express lanes, described them as an Interstate within an Interstate. I thought that was a pretty good line, especially after getting a ride in the lanes, because I didn’t feel like I was just driving on the left side of a wider Beltway.

After the express lanes open on Nov. 17, you won’t be sliding in and out of them with simple lane changes along their 14-mile course between Springfield and the Dulles Toll Road. Except for the start and the finish, your entering and exiting opportunities are at interchanges. The exits from the lanes will be on the left sides. And drivers entering the lanes will come in from the left sides.

Some of these exits will be new ones, exits that drivers don’t have access to from the regular lanes. The Tysons access points at Westpark Drive and Jones Branch Drive are often described by project managers as new drains in the bathtub, because they provide new access.

Don’t be thinking of these access points as new HOT lanes ramps parallel to the old, curving ramps for the regular lanes. Many of the express lanes connections involve “T” intersections, controlled by traffic signals.

And don’t be looking for exit numbers from the express lanes. You will see plenty of signs giving road names and route numbers. For example, you will see exit signs for “Jones Branch Road” or “267” north of it, but no numbers have been assigned to the exits.

Check my Commuter page guide to the entrances and exits, and the signs drivers will see along the way.

Here’s a link to a guide for the three Tysons access points along the express lanes.

Here’s an older guide to how the HOT lanes work. I plan to update some of that information in a Commuter page feature on Nov. 18, the eve of when many drivers will get their first experience with the lanes. (Example of a change: In that 2010 feature, one of our artist’s renderings of the signs shows it reading “HOT Lanes.” You won’t see such a sign, because these Interstate signs are regulated by the Federal Highway Administration. You’ll see signs that say “E-ZPass Express,” like the one in the photo at the top of this posting.)

The lane operator also has a great deal of information on its Web site:

Many more questions about the new lanes came in during Monday’s online chat, and I plan to address them in future postings.