HOT Lane Data Through 12/02/11

Here’s the updated spreadsheet of HOT lane data compiled from press releases from SRTA.


  1. bullFrog says:

    Just a few observations:
    1) Weekend data not included. Would expect that to bring the travel times closer – not that it means anything.
    2) Average toll price? Guessing total revenue / number of tolls collected? Indicates not a lot of end-to-end trips.
    3) What’s going on with “lane violators?” I see these on a daily basis on my trips. Any enforcement going on?

    Looking forward to the day this idiotic experiment ends … just sayin’.

  2. Engineer says:

    With all the complaining blog posts/threads about these HOT lanes (that include data), one thing keeps bothering me. Where is the baseline data for the number of drivers before the HOT Lanes were implemented? Without a baseline, you really have nothing to base a complaint on.

    • bullFrog says:

      Yep, pretty much everything is anecdotal. The holders of the data probably won’t release anything that doesn’t support whatever their pre-selected conclusion happens to be. Even then, it will be suspect (Have you heard how much unemployment has fallen?)

      Another observation: the past two days, there has been a Gwinnett Transit bus traveling the full length of 316-to-Spaghetti Junction in the center lane; never making an attempt to get over to the HOT lane. And the driver appears to ride with his/her foot on the brake as the brake lights never stop going off and on the whole trip. Annoying in two ways.

    • Dave Bearse says:

      There very likely isn’t any, or the AJC would be publishing it.

      With no baseline to base complaints on, the implementation was lacking in competence, or to provides a means to dismiss criticism of the HOT lanes with respect to congestion as anecdotal.

      We know the costs, $50M and a few million a year to operate. The benefits for an Engineer’s B/C ratio? Not available.

      • Charlie says:

        Actually, when I met with Dr. Evans before the HOT Lanes were implemented, one of the points she stressed was that this was a demonstration project, and that the effects before and after were to be measured over a five year period. I distinctly remember part of the conversation including at least one baseline study, and if my memory serves, there were at least two. One a year or more before implementation, and one just before implementation.

        Thus, there’s a baseline out there.

        • Dave Bearse says:

          Charlie, the HOT system pings tags on vehicles in eveny lane at selected locations, not only the HOT lane. The information is used to determine general purpose lane speed information that then is used to set the HOT toll.

          It’s not rocket science (even though rocket science-type money may’ve been spent) to have decided to ping vehicles for a few weeks in advance of the HOT lanes going in service to develop a definitive general purpose and HOV lane baseline. The baseline would provide exactly the same “before” information that is in Buzz’ after spreadsheet, except change HOT to HOV that there would be no definitive HOV lane volumes.

          Buzz, if you read this, perhaps you’ll consider requesting that information. The availability of that information would eliminate this particular criticsm of HOT lane implementation of mine. It would make clear whether general lane speeds increased or decreased since HOT lane implementation.

          • Harry says:

            And if there was little if any change, what would that tell us? That the HOT lanes are just an attempt at revenue raising and not likely to add much revenue net of start-up cost and operating expenses? Just because our masters imagined it to be a good idea, doesn’t mean it is a good idea.

            • Calypso says:

              If there is ‘before’ data available, my guess is the powers that be don’t want it to be made public at this point.

              • The Last Democrat in Georgia says:

                The ‘before’ data would probably be buried in the same desk drawer under the internal report stating that converting HOV lanes to HOT lanes would make traffic worse in the general purpose lanes.

                But at this point, who’s to say that data does or ever did exist? Good luck getting anyone in state government to acknowledge that it ever did.

                • analogkid says:

                  You should send SRTA an Open Records request. If they’ve got the data, they have to provide it to you in three business days. It’s worth a shot.

                  • Charlie says:

                    I didn’t mean to make it sound like it’s a conspiracy. I just said the data is there. Has anyone asked for it?

                    I’ve had many other fish in line to fry, and this hasn’t yet been one of them. I’ll re-engage on this issue when I’m caught up on my other stuff. Or, at least pretend its under control…

                    • analogkid says:

                      Sorry. I was responding to LDIG and Calypso. If the data is out there and one of them (or anyone else) wanted it, I was attempting to make sure they knew there was a process in place for that sort of thing.

  3. benevolus says:

    I think all you really need to know is number of cars that used the HOV lane vs. number of cars using the HOT lane. If you’ve got the same number of lanes but now fewer cars in one of them, the excess is going somewhere. Even if it’s not going into the regular lanes or being spread out over a longer time period, the bottom line is that the HOT lane would not have reduced congestion. But I don’t think it was designed for that purpose anyway. It seems almost automatic that if they are trying to keep the HOT lane fast moving the other lanes will be less so.

    • Engineer says:

      This is exactly my point. I just want traffic counts for that lane for a before and after look. If you have more cars on the lane than before, then I would consider it a success. Although it is still too early for the HOT Lane data as people are just getting into the hang of it, but thus far the average seems to be around 10-11k per day (as long as you ignore the holiday week of Thanksgiving).

      • Dave Bearse says:

        Congestion determination revolves around speed, not volume. Traffic volumes don’t provide definitive speed information, though Traffic Engineers can provide good estimates if the time period is small. Volume per day is rather useless, volume per peak period is nominally useful, but volume per hour or less is needed for good determinations.

        It’s well established that traffic volume increases to an approximate nominal 2000 vehicles per lanes per hour as speed decreases to a steady flow roughly 25mph. Additional traffic seeking to use a lane carrying 2000 vpd causes traffic flow to become unstable, changing to stop and go or worse, and the traffic volume handled by the lane decreases. Very roughly, think of a bell curve with y-axis traffic volume and x-axis avg speed and maximum at 2000 vehicles per lane per hour and speed of 25mph. Given a volume of 1,500 vehicles per hour in a lane, the average speed could be say a free-flowing 40-45mph, or a stop and go 15mph depending on the side of the peak.

        Simply stated, the criticism is why use estimates and calculations for speed estimates when true “before” speed could have been easily and directly measured by a multi-million dollar system in place and designed to do exactly that?

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