I had an entirely different topic prepared for Gridlock Guy this week, but my inbox had different ideas. Since last weekend’s immense construction delays on I-75, multiple AJC readers and WSB listeners have reached out about the direction that the new Northwest Metro Express reversible toll lanes run on the weekends. There is quite a bit of confusion, as the rules for weekend lane reversals are completely different.

» RELATED: Gridlock Guy: New I-75 Peach Pass lanes making impact, so far

The normal ebb and flow of the brand new, raised toll lanes is for them to run in the rush hour direction on weekdays. So they run southbound on I-575 and I-75 during morning commutes and northbound in the afternoons. GDOT HERO units and law enforcement close the lanes at approximately 11:30 a.m. Monday thru Friday to properly flush the lanes of any traffic, debris, and stalls. Then they open the gates in the northbound direction at 1 p.m., ahead of the afternoon commute.

Crews then close the express lanes on weeknights around 11 p.m. and re-open them at 12:30 a.m., ahead of the next weekday’s AM drive. This same process is in play for the South Metro Express Lanes on I-75 in Henry County, except in the reverse directions, of course. And the State Road and Tollway Authority (SRTA) needs a 30 minute stagger between when the two different lane systems reverse, so the Henry County lanes begin their process before Cobb and Cherokee. But what happens Saturday and Sunday has left motorists scratching their heads.

As Cobb and Cherokee commuters have happened upon the I-75 and I-575 toll lane system these last three weeks, they have expected the lanes to operate in the same directions during the weekend as they have during the week. Those freeways were in decent shape the first two cost-free weekends after the lanes’ opening, so the need to use them didn’t exist. But I-75 in Marietta was a disaster the past weekends, with three or four lanes blocked in each direction near the South and North 120 Loop exits both Saturday and Sunday. People actually wanted to use the lanes then.

But multiple people leaving Downtown Atlanta and driving home to the northwestern suburbs on the afternoons of September 22nd and 23rd were shocked to find the Peach Pass lanes still pointed in the southbound direction. This is because SRTA and GDOT have had a general rule of thumb of putting the lanes in direction needed for Monday’s morning drive very early in the weekend.

» RELATED: Gridlock Guy: Officials explain the new Peach Pass lanes on I-75 and I-575

But after checking traffic flow data (the delays), SRTA is amending when the lanes change on both sides of town. Starting with this past Friday’s PM drive at 10:30 p.m., crews in Cobb and Cherokee each weekend will close the lanes and reverse them from northbound to southbound by 1 a.m. The lanes will then stay southbound until 11:30 a.m. Sunday, reverse to northbound by 1:30 p.m., then stay that way until 11 p.m. Then crews will reverse the lanes again back to southbound by 1 a.m. and well enough in time for Monday morning drive.

On the south side, the reversible express lanes stay southbound direction from after Friday PM drive until about 11 a.m. Saturday. Then the lanes re-open northbound at 1 p.m. and stay pointed that way until 10:30 a.m. Sunday. The lanes will then close for two hours and run southbound until 11 p.m. Sunday, before closing again and reversing to the northbound direction for Monday’s commute. Rules change during holiday travel weekends, though this new schedule benefits those travel patterns more than before.

In general, the lanes do not follow the weekday rush hour schedule on the weekends, because there isn’t a scheduled weekend rush hour.

Since construction crews blocked up both directions of I-75 September 22nd and 23rd, this didn’t matter. One side was going to have the lanes and one was not. Both needed them. But what if there is construction on only one side of I-75 or I-575? Will GDOT and SRTA change those procedures to cater to projects?

In talking to officials, they haven’t ruled out the idea of pre-planning express lanes reversal times. But this takes a lot of coordination. Construction crews actually have to close the lanes when and where they say they are going to do these projects. Both GDOT and SRTA have to work together to make these schedule changes hours, if not days before the scheduled event. As we have learned, reversing the lanes takes at least an hour and a half. This coordination effort is precisely the reason that they cannot just up and reverse the toll lanes because of something more ephemeral, like a big crash.

If you're planning traveling on the north or south sides of town on I-75 and I-575, plan ahead. Check the schedules for the Northwest Metro Express Lanes or the South Metro Express Lanes to know if you will even be able to use your Peach Pass. Besides reading the overhead digital signs, one can check the pricing and direction of the lanes real time on PeachPass.com. Follow the tabs "Peach Pass," "Pricing," and "Live Toll Rates" in that order. This feature isn't available in the mobile app.

Hopefully officials can plan more flexibility in these lanes around special events and major road projects in the future.

» RELATED: Here's what happens if you use the Peach Pass lane illegally

Doug Turnbull, the PM drive Skycopter anchor for Triple Team Traffic on News 95-5 FM and AM-750 WSB, is the Gridlock Guy. He also writes a traffic blog and hosts a podcast with Smilin’ Mark McKay on wsbradio.com. Contact him at Doug.Turnbull@coxinc.com.