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Transportation Science

Getting Rid of Carpool Lanes Could Double Travel Times (sciencemag.org) 245

An anonymous reader quotes a report from Science Magazine: Eliminating carpool lanes could almost double drivers' traveling times, according to a new study. The findings come thanks to an unusual decision made by the government of Jakarta last year. Following allegations that drugged babies from poor households were being used as "jockeys," or passengers for hire, Indonesian lawmakers repealed the so-called three-in-one restriction. The law had required cars driving on the business district's main roads to carry at least three passengers during rush hours. To determine the impact on the city's drivers, Benjamin Olken, an economist at the Massachusetts Institute of Technology in Cambridge, and colleagues queried Google Maps for real-time driving-speed data before and after the new policy went into effect. Following the policy lift, travel delays, defined as the time it takes to travel 1 kilometer, increased by 46% in the morning and almost 90% in the evening, the team reports today in Science. But the most startling result is that phasing out the three-in-one policy led to worse traffic during times of the day and on roads where there had never been restrictions in place, Olken says. One possible explanation, he says, is that the three-in-one restriction led fewer people to drive into the city. "Maybe they carpooled, took public transit, or worked from home."
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Getting Rid of Carpool Lanes Could Double Travel Times

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  • False Scarcity (Score:2, Insightful)

    by FrankHaynes ( 467244 )

    In the USA they take away "free" travel lanes, then sell them back to you as carpool/HOV/HOT lanes. This creates scarcity and increases congestion in the existing lanes and makes the relatively quicker toll lanes more appealing, which fills up the government coffers. Sweet little scam.

    So it's doubtful that getting rid of toll lanes would increase congestion, rather it would restore highway capacity so traffic should flow better.

    • Re:False Scarcity (Score:5, Insightful)

      by bug_hunter ( 32923 ) on Thursday July 06, 2017 @11:54PM (#54761369)
      Well, this is an article about how someone published a scientific paper about how removing carpool/HOV/HOT lanes increases congestion.

      In fairness what's true in Jakarta may well not be true for America, but I think you have to give some more reasoning as to why the article is wrong.
      • I'm quite certain that what applies in Jakarta does not apply in the USA. For one there are far fewer people in the USA willing and able to drug their children to hire themselves out to fulfill a HOV lane requirement.

        I say willing because people in the USA generally don't seem as desperate. I'm not saying they don't exist, just fewer. I say able because any drugs worth a damn are prescription only in the USA. Sure, you can get a Tylenol or something over the counter but if have anything more than a mild

    • In Silicon Valley there's a noticeable slowdown at 3:00 when the carpool lanes turn on.

      Clearly there are two cases:
      1) HOV lanes slow everyone down because not many people carpool
      2) HOV lanes speed everyone up because they cause people to carpool

      You should be able to calculate a crossover point, where the number of carpoolers is sufficient to overcome the loss of the lane. It's not just total carpoolers, it's the delta.
    • another way is that toll roads exist to force the poor to use slower, crappier modes of transit. Hell, our entire car based society exists for that. We all suffer through wars, air pollution and an overall lower standard of living save for a few so well off they can stand above it. And most of them still spend 90 minutes a day commuting. And even if we ignore all that toll lanes are still a regressive tax, disproportionately hurting lower wage earners for whom the tolls represent a larger percentage of thei
      • by AmiMoJo ( 196126 )

        Why can't the poor just use the "high occupancy" option? I thought that just meant >1 person in the car, which makes sense if you are poor because it's cheaper than two people driving two separate cars to work.

        • by tepples ( 727027 )

          When all lanes are HOV-only (read the article), carpooling works only if both people live in the same place and work in the same place. When a person drives alone to pick up the person who carpools with him, he violates carpool law. When a person drives alone after having dropped off the person who carpools with him, he violates carpool law. Or should people instead choose a roommate based on having the same place of employment?

        • by spitzak ( 4019 )

          The poor are more likely to have jobs they have to arrive at time at, making it harder for one of them to take a detour to pick up another one. I have carpooled but I would not be considered the lower class, and I can certainly see how this would be far more difficult if my time for travel was limited.

    • They created more accidents on I-405 on the Eastside. The collector / merge lanes cause dramatic speed changes in the high speed "normal" lanes as traffic enters and exits the tolled lanes. Even in periods tolls aren't charged. They have revised the enter and exit lanes twice now. Still not working. They took one carpool lane and made it two tolled lanes expanding the roadway while narrowing the existing lanes. Another safety bad move.

      But the worst is that 30 percent of the tolls go to a private firm, out
    • by swb ( 14022 )

      I'm pretty sure the signage, toll collection systems (FastPass, etc) and road modifications for carpool lanes cost way more than the revenue from tolls brings in. It's hardly a money maker.

      It's also doubtful that the traffic would move appreciably faster if the toll lane was an ordinary traffic lane. Usually these systems are implemented at some point where traffic levels have exceeded roadway capacity, so you were already going slow.

      In fact, the larger problem is that demand exceeds supply at the price o

      • Apparently you don't have variable toll rates on your express lanes. In Atlanta, there are express lanes going up that have variable rates that are determined by monitoring the express lane speeds. If the express lane starts to slow, the tolls go up. They vary from a few pennies when there is no traffic to tens of dollars in rare cases.

        • by swb ( 14022 )

          That's how demand pricing works and that's how it works here, too.

          As demand increases, the price is supposed to increase to cut demand. The higher prices should force people for whom the additional dollars aren't worth the additional speed to not use the express lane.

          Knowing what I do about Atlanta roads, my guess is the congestion is so bad that the price ceiling for a lot of drivers is very high and they are willing to pay a large sum to stay in that lane.

          There's also the question of casual users. In Mi

    • by dfm3 ( 830843 )
      I don't think that's quite right. Do you know of a city in the USA where the number of free travel lanes on an interstate has been reduced to accommodate HOT lanes? The ones I'm familiar with, the HOT lanes were added onto the shoulder or median. The northwest corridor project in Atlanta, for example, the new lanes are being built above the existing travel lanes on a causeway. IIRC there is even a federal law that prevents any more existing interstate lanes from being converted to toll.
    • by eepok ( 545733 )
      You're mixing terms but not 100% correct. Carpool/HOV lanes are rarely toll lanes so they're not sold back to you. They're restricted lanes for vehicles with 2+ or 3+ people in the vehicles. In all reality, if you gain a carpool partner, chances are that that person is sharing the cost of the commute and parking with you and thus you're obviously saving money.

      However, you are correct in the effort to create artificial scarcity. And that's not hidden. The goal of a carpool lane is not necessarily to bene
    • In the USA they take away "free" travel lanes, then sell them back to you as carpool/HOV/HOT lanes. This creates scarcity and increases congestion in the existing lanes

      Evidence, please. It is quite possible that the carpooling encouraged by this reduces the overall traffic so that the non-HOV lanes, while more congested than the HOV lanes, are less congested than they would be if there were no HOV lanes.

      So it's doubtful that getting rid of toll lanes would increase congestion, rather it would restore highw

  • Its possible that Braess's Paradox [wikipedia.org] is to blame here also?

    In a nutshell, it can be that if people are given too much license to make "selfish' decisions, it can actually increase travel times across the system. (E.g. if people keep changing lanes to get ahead but cause others to slow down resulting in a net negative to the system).

    There are examples of this occuring when new "improvements" to motorways added to a system actually caused traffic delays, which only went away when the new road was closed.

    • Read the summary again, it's not a carpool lane, it's ALL traffic.

      Whoever wrote the article needs a kick in the crotch.

      • Re: (Score:3, Informative)

        by netlag1 ( 4094715 )
        I RTFA and it does say it wasn't carpool lanes that were removed... 3 passengers were required to use the road at all.

        So if you remove the 3-passenger requirement, capacity will not change but usage will increase, so of course it will slow down. If you change a carpool lane into a regular lane, capacity will increase, and depending on how much usage increases traffic can speed up or slow down.

        Read the summary again, it's not a carpool lane, it's ALL traffic.

        Whoever wrote the article needs a kick in the crotch.

        • Yes, we're in furious agreement... excepting that the article title and first paragraph both misrepresent the study.

    • In a nutshell, it can be that if people are given too much license to make "selfish' decisions, it can actually increase travel times across the system. (E.g. if people keep changing lanes to get ahead but cause others to slow down resulting in a net negative to the system).

      You forgot the chucklefucks who don't know what lane they're supposed to be in who create the inducement to others to change lanes to try to get ahead. That's the first selfish decision in that chain.

      • by swb ( 14022 )

        The passing lane concept breaks down in many urban areas which have freeways with road splits, left exits, lane shifts -- and traffic volumes high enough that it makes sense to fill all the lanes and not leave one empty for passing only use.

        On more than one occasion I've seen the "relentless lane changer" successfully weave their way through traffic only to find myself right behind them at some traffic light at the highway exit. They've managed to get 2 minutes ahead just to wind up 0 minutes ahead near th

        • The passing lane concept breaks down in many urban areas which have freeways with road splits, left exits, lane shifts -- and traffic volumes high enough that it makes sense to fill all the lanes and not leave one empty for passing only use.

          It doesn't have to be left empty, the rule is that if you're not passing, you get out of it. Somewhere up ahead, there's always someone not following that rule. The two types that really steam my clams are the people who slow down to pass, and the people who are afraid of Jersey barriers that crop up around construction sites. That stuff isn't in their lane, but they're afraid of it anyway, because they know they can't stay in their lane... in which case, they should slow down, and pull over to a lane which

          • by swb ( 14022 )

            Still, you can't avoid the problem that during periods of congestion all the lanes end up full. Keeping one lane mostly empty wouldn't seem to accomplish much but reduce total capacity and push congestion back.

            And it does nothing for situations where the entire freeway splits in two to go different directions, in many cases if you're not in that half of the freeway a half-mile or more before the split, you're not easily getting into that half.

            I will say that the passing lane concept should be followed fair

        • It's not the speeds that are important to commute times, it's the following distance. And the following distance also causes the weaving. There is a small subset of poor drivers that leave ridiculous gaps in traffic as they "aren't in a hurry" to catch up to the pack in front of them. Except they are just wasting the space of cars (sometimes dozens of cars worth of space) forcing the traffic jam to extend backward faster. In traffic, you have to pack in tightly to maximize the flow rate of the road. I recal

          • by swb ( 14022 )

            The problem around here seems to be that a safe stopping distance between you and the car in front of you is invitation to a weaver to change lanes, and usually results in an unsafe following distance, requiring everyone to slow down.

            IMHO, you shouldn't change lanes unless the gap you're merging into is some multiple of the safe following distance of the cars you're merging between. This prevents the rear car from braking to slow down to re-create the safe following distance.

            I also think that safe followin

            • The problem around here seems to be that a safe stopping distance between you and the car in front of you is invitation to a weaver to change lanes, and usually results in an unsafe following distance, requiring everyone to slow down.

              The root problem that causes that problem is, you guessed it, people who don't belong in the passing lane being in the passing lane. They don't seem to comprehend that if their pulling out causes someone else who is attempting to pass to have to slow down that they are fucking up. If they would just stay out of the way of people who want to go faster, then the highway's capacity would increase significantly. Of course, that means some people would be stuck behind a truck for the entirety of their journey, b

              • by swb ( 14022 )

                I watch this. Every. Single. Day. And the person who wants to pass never gets very far, not because some slow driver is in their way, but because the traffic is beyond the road capacity. Passing one arbitrary slower driver simply presents them with another driver in front of them, probably who wants to go as fast or faster than they do, ad infinitum.

                The traffic level is simply beyond the capacity of *both* lanes. You couldn't maintain the "passing" lane free for passing because if it was empty enough

            • If all they did was slow slightly, that might be true. The drivers with excessive following distances also tend to over brake causing a lot of the problems... They are also slow to accelerate when traffic frees up. They are just timid drivers that don't feel comfortable in traffic and they cause most of what they fear.

              The number one thing I yell in traffic is "Why are you braking?" It just seems to be the default response to any event for most drivers.

        • t=d/v

          r * t = d

          If v is zero, your equation results in an undefined value.
          Further, there's the distinction between rate and velocity (which is a vector). See also distance vs. displacement (and how they both start with a d).

  • So they implement a policy that cars must have passengers to use main roads. So people "hire" (that word used in the articles) passengers to get around the law. Since screaming kids is not something people are willing to pay for the kids are drugged to stay quiet.

    So, they can choose seeing kids drugged or they can choose longer commutes. They chose longer commutes.

    Who was it that said for every problem there is a fix that is easy, simple, and wrong? I believe that applies here.

    • Yup. What they should do is just do an odds and evens system.

      Rich people can have 2 cars and drive every day, most people can carpool with a neighbour.

      Then you can just have plate scanning cameras issuing the fines.

      • That sounds like another fix that is easy, simple, and wrong.

      • by tepples ( 727027 )

        most people can carpool with a neighbour.

        Only if A. they work at the same place and at the same time and shop at the same place and at the same time, and B. they weren't issued plates whose last digits are the same modulo 2.

  • In California they have carpool lanes that have variable pricing depending on the time of day and the congestion on the road at that time. Similar and probably the inspiration for Uber's "Surge Pricing".

  • by s1d3track3D ( 1504503 ) on Friday July 07, 2017 @01:12AM (#54761641)

    Following allegations that drugged babies from poor households were being used as "jockeys," or passengers for hire

    Holy crap, if this is true I would think that congestion traffic is the least of your worries...

    • Following allegations that drugged babies from poor households were being used as "jockeys," or passengers for hire

      Holy crap, if this is true I would think that congestion traffic is the least of your worries...

      I'm surprised that isn't getting more discussion here. Did people miss that or is it that people don't think that is a problem?

      Then again, I don't want to know the answer. I'll just believe what I want to believe.

      • Why this isn't discussed here? Consider: What would the average /. reader be more likely to encounter in his life?

        Contested traffic
        or
        Children

  • The thing I don't understand is that they aren't really carpool lanes. They are party car lanes. If you bring extra bodies you go faster. So you get people trying to convince their friends and family to go with them instead of going alone. The additional weight in the vehicle burns more gas but you get where you want to go faster so it's probably worth it even to poor Indonesians. Still it must waste and burn a lot of extra fuel.

    The whole idea of carpooling is kind of ridiculous. Most neighbors don't have t

    • Yes, that's what Jakarta needs: More motorcycles and the horrible accidents that come with them.

      And before someone answers, this is more a statement about the way people drive in Indonesia than motorcycles. I love my bike. But I'm not suicidal enough that I'd drive it there.

      • by ghoul ( 157158 )

        Traffic in Jakarta is so sow that I highly doubt any accident is fatal.

        • The speed of the car running you over isn't the deciding factor concerning your survival chances when you fall off your bike.

    • by kenh ( 9056 )

      The additional weight in the vehicle burns more gas but you get where you want to go faster so it's probably worth it even to poor Indonesians.

      Run the numbers, the math is straight-forward.

      If one person in a car travelling a certain distance consumes "x" amount of gasoline, will three people in one car travelling the same distance consume 3x the amount of gasoline or some amount less? Common sense tells us less, and that saved fuel, which in turn results in less greenhouse gasses being generated is the motivation for car pool lanes. Faster travel time is the incentive to car pool.

      EXCEPT this story isn't about car pool LANES, it is about car pool R

    • by stdarg ( 456557 )

      This is actually an area where a little bit more government involvement could be beneficial. It seems like the only way to make it work would be if more facilities were provided to carpoolers, such as free parking lots where riders could connect. It would be kind of like a bus station without the buses.

    • by orlanz ( 882574 )

      Riding with neighbors and friends isn't how carpooling works anywhere. Usually for routine travel where the majority of the distance is the same, a bunch of random people meet/pick up at certain points and journey together. They come from close enough places and go to close enough destinations. Its a personal & predictable ride share.

      Another form of this has actually been quite common for decades in most developing countries. There are "shared" taxis with extra seats that pick up and drop off people

    • by Altrag ( 195300 )

      Generally you wouldn't be carpooling with your next door neighbor. Typically, at least in concept, you'd be carpooling with a coworker or someone from a nearby business who lives in the same general direction as you even if they're a couple miles away. Or better yet, many such someones.

      The idea being that the time spent running around picking up all those people is comparable to or lower than the amount of time spent idling in traffic on the "high"way, and of course for the last person on the pickup route

    • Carpooling really only works for school. Everyone is headed to and from the same place at the same time.
  • The root cause is government pricing something in great demand too cheaply. It happens all the time, water, parking, road access, ...

    Government should institute congestion pricing for such districts . Vaguely recall London does this. If people are paying for passengers or renting drugged baby (just one case, despite the prominent mention in the summary) they would pay the tolls. Impose the toll on vehicle not on number of passengers. Keep raising it till employees refuse to drive to work or demand compens

  • The law had required cars driving on the business district's main roads to carry at least three passengers during rush hours.

    The gov't eliminated the requirement that ALL cars driving on certain roads needed to carry 3 or more passengers, it didn't remove carpool lanes along those roads.

    Under the old law EVERY CAR on certain roads were required to carry at least three passengers, cars with fewer passengers were prohibited. Once the "three or more" requirement was lifted, the streets in question were, as one would reasonably expect, flooded with more cars.

  • I regularly travel all around southern california and the HOV lanes are always always slower than the regular lanes. What's worse is having to stop in a HOV lane while regular traffic lanes keep moving. This is compounded by idiots who insist on going exactly 65mph (or worse 55-60 because muh fuel economy) instead of the speed of traffic which regularly hits 76-78.

    What they need to do is set the speed limit in HOV lanes to 80mph and set a minimum speed of70mph (enforced by camera). That would solve the slo

    • It's been awhile since I traveled in the bay area. But when I was there the HOV lane was frequently the only lane moving at more than 10mph during peak hours. In fact I remember moving over into the HOV lane was always a little harrowing because you had to get up to speed very quickly to avoid an accident. We could often spend more time merging from the on ramp and across four or five lanes of traffic to the HOV lane, and then reversing that process at the exit, than we spent actually in the HOV lane.

  • Instead of minutes/kilometer (with an implied 'per vehecle'), how about minutes/kilometer/person?

    • by sl3xd ( 111641 )

      Does "per person" matter in this case? The jockeys rode as cargo - they weren't interested in the destination.

May all your PUSHes be POPped.

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