By on September 16, 2008

Driving well has nothing to do with how well we late-apex Oaktree Corner at VIR, how cleanly we rev-match a heel-and-toe downshift or how much we know about F-bodies and Kappa platforms. It’s all about simple movement and complex congestion, intuition versus intelligence, myth versus reality. Why We Drive the Way We Do by Tom Vanderbilt is a shot across the bow of the typically clueless, not very competent, generally thoughtless, surprisingly unsafe, unjustifiably over-confident average driver. In other words, you and me.

Take the common task of merging from three lanes into two. Polite drivers will segue into the next lane as soon as they can. Jerks will stay in the closing lane all the way to the end, then force their way in. As Vanderbilt correctly argues, these “jerks” actually help traffic move faster. If a larger number of motorists simply followed their lead, stayed in the “open” lane to the bitter end and THEN alternate-merged into the funnel, everyone would get where they’re going more quickly.

Or say you’re in a line of fast-moving cars following somebody in your lane who slows quickly— maybe he’s been cut off, or is about to miss an exit. You’re third in line and so skillful a wheelman in your Brembo’ed BMW that you can follow the car ahead pretty closely and still brake safely. Unfortunately, the six cars behind you each progressively uses up the rapidly closing gaps that you have single-handedly created, and the tenth car in line has a huge and unavoidable rear-ender that you caused.

Traffic driving is filled with visual illusions and sensory tricks. SUV and pickup truck drivers tend to go faster without knowing it, because they’re just that much farther above the road. They’re just like early 747 pilots who tended to taxi at speeds that could damage the landing gear, because they’d never sat that high above a taxiway.

Traffic has many facets. We communicate in traffic with bumper stickers announcing that we’re religious, liberal, ex-Marines, whale-savers, parents of teachers’ pets. Yet the little billboards are counter-communicative. Beep to try and say Semper Fi and you’ll get the finger. (I was leaving the gym in our Boxster awhile ago and found myself right behind a woman in a near-identical Boxster, waiting to enter the highway. I gave her a “Hi, Porschie fan” toot and got, yes, the deadly digit.)

Parking is an inevitable part of driving. Why do many people park substantially farther from the big-box store if they have a sightline to the front entrance, even if there are closer spaces off to either side? Some drivers are active parking searchers, endlessly cruising to look for a spot, like an orbiting hawk. Few can bear to be owls, perching in wait for a shopper to come out of the mall to follow them and take their spot. In one survey of a 15-block area near UCLA, a survey discovered that people looking for parking drove 3,600 miles a day.

Driving involves not just seeing but knowing what to do with the information you thus collect. A driver in Maine will brake immediately for a moose but less quickly for a zebra, since he has to process an unfamiliar situation. When the light turns yellow, you need to quickly make the correct decision: push through and run the slight risk of getting heavily T-boned by a green-light jumper, or stop quickly and run the more substantial risk of getting into a minor rear-ender.

Traffic is stuffed with seemingly random but always instructive factoids…

We constantly see other drivers making mistakes but are unable to see ourselves doing so.

We often drive at a distance behind the vehicle ahead that far exceeds our ability to avoid a crash, because we have blind faith that the driver in front of us will never, ever need to stop quickly.

Drivers prefer waiting in a single long line than in multiple shorter lanes, because they hate the stress of worrying that the other guy has chosen a faster lane.

Rubberneckers create the perfect self-generating traffic jam, and people slowing to look at an accident get into accidents themselves.

If you drive an average of 15,500 miles a year, there is one chance in 100 that you will die in a fatal car crash over a 50-year lifetime of driving.

The most dangerous vehicles on the road are… pickup trucks. More people die in pick-’em-ups per 100m miles driven than in any other vehicle.

Stirling Moss once said “There are two things no man will admit he cannot do well: drive and make love.” But then smarter Albert Einstein said, “Any man who can drive safely while kissing a pretty girl is simply not giving the kiss the attention it deserves.” Go figure.

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54 Comments on “Book Review: Traffic: Why We Drive The Way We Do (And What It Says About Us)...”


  • avatar
    AKM

    The New York Times had a long article about that as well, and it is very interesting, if only to force us to contemplate our shortcomings. I try to make objective decisions, but often fail. I know it, and yet do it nonetheless (such as being right on somebody’s bumper, to “push” them out of the way), because I have the self-righteous feeling that that slow car shouldn’t be in a passing lane.

    Take the common task of merging from three lanes into two. Polite drivers will segue into the next lane as soon as they can. Jerks will stay in the closing lane all the way to the end, then force their way in. As Vanderbilt correctly argues, these “jerks” actually help traffic move faster. If a larger number of motorists simply followed their lead, stayed in the “open” lane to the bitter end and THEN alternate-merged into the funnel, everyone would get where they’re going more quickly.

    I’m fine with those, but what about the people who leave the left lane to go into the right lane, pass a few cars, and then slow the whole traffic by pushing their way back in?

    If you write a book review, could you include separately from the body of the review the full title, author, editor, and retail price? That’s what’s generally done in most publications, and helps readers to find that information quickly.

  • avatar
    geeber

    Interesting article, although I think that one quote needs to be put into context:

    “The most dangerous vehicles on the road are… pickup trucks. More people die in pick-’em-ups per 100m miles driven than in any other vehicle.”

    I recall reading that drivers of pickup trucks are less likely to use seat belts than drivers of other vehicles. They are also more likely to be driven by young men (especially the compact pickups).

    I also see more old pickups on the road than any other type of vehicle – especially in rural areas. Those old pickups don’t have the latest safety equipment.

  • avatar
    tommy!

    I think so many people fail to realize that each and every time they close the door and buckle their seatbelts (as they should be doing) they are piloting themselves into the most life-threatening part of their day.

  • avatar
    Martin Schwoerer

    Great surprise to see this here. I’m reading the very same book, and find it intriguing, with some new insights every few pages. It’s good news that TTAC is doing book reviews!

  • avatar
    MX5bob

    Drivers are their own worst enemies, especially in rush hour.

  • avatar
    menno

    There’s a Menards near us, and it’s notorious for having idjits pulling out and making left turns onto US 31, which is 2 lane at that spot.

    Two thanksgivings ago, my wife and I had just picked up about 40 turkeys from a local La Seniorita restaurant (as a gift for the church food pantry) and I was following her in my car.

    Bingo the evil clown pulled out from Menard’s and essentially, drove her right off the roadway – she’s an excellent driver (having lived in the UK she has excellent driving skills and reflexes) and she managed to stay on the wide shoulder common here in Michigan without mishap. I called the cops – they did nothing.

    Contrast my buddy who last Saturday, was following his wife back from town in his SUV; he told me exactly the same thing happened, but instead of troubling the police (who apparently could not care less), at the next red light, he stepped out, walked forward 2 vehicles and pounded on the guy’s window – screaming at him at the top of his lungs. Until the light turned green. He said the guy just grinned at him (behind locked door, no doubt).

    I told him he was lucky to be alive. But he hasn’t listened to me since we were 14 and why start now, at age 51?

  • avatar
    ttacgreg

    I have always gone to the furthest extent possible in a lane that is closing, after all it is not closed until it is closed. I have had an occasional self righteous controlling other driver physically block me, but what the hell?
    Recently here in Colorado the highway department must have a clue, they have posted signs at road construction sites telling drivers to do exactly what I do, occupying the lane up to the point of merger.

  • avatar
    thetopdog

    I am an aggressive driver, but I wouldn’t call myself inconsiderate. One thing that’s worked for me is asking myself the following: “If everybody drove like me, would there be more accidents and/or pissed off people?”. If the answer is “no”, then I don’t feel bad about driving the way I do. This means that I don’t feel bad about doubling or tripling the speed limit where appropriate, but I never fail to use my turn signals.

    I thought this was extremely interesting:

    “Drivers prefer waiting in a single long line than in multiple shorter lanes, because they hate the stress of worrying that the other guy has chosen a faster lane.”

    I know it’s not entirely rational, but I get very stressed out when there are two lanes I can choose to wait in and my lane may be the slow one. It doesn’t make much sense, but it must raise my blood pressure by at least 10% when it happens. I will go out of my way to avoid these places during my commute

  • avatar
    Morea

    Mmmmm, Oaktree Corner… I wish I were apexing there right now!

  • avatar
    B.C.

    Trying to find street parking near UCLA is a worst case scenario. I’m not surprised.

    Also, I’ve run into that “zebra” situation before. I’ve hit a white owl in the middle of the road and barely swerved around a peacock on two separate occasions, both times while wondering what the hell was going on.

  • avatar
    gamper

    Allright, I am the jerk the runs up to the point of a merge. I dont do it because it actually helps traffic, I seriously doubt that it does. I do it because I refuse to sit there watching the traffic fly by and cut in at the last moment as I crawl up to the front.

    Perhaps if everyone did like the author suggested and alternated merges it would help traffic, but that never happens, and never will.

    Since that never happens, those in the lane being closed get through the bottleneck 20 times quicker by driving up to the front and since their motive has nothing to do with helping the flow of traffic, they are still just jerks (like me). Lets not kid ourselves.

  • avatar
    gamper

    Menno,

    Just had to add that I grew up in Grand Haven, not far from you apparently.

  • avatar
    mykeliam

    The guy has got a point. But, he misses the fact that the roads were built not by forward thinking people. Here in the steel city (Pissburgh), the plan in the 50′s was for twenty years into the future. Now it’s almost 2010 and traffic has exploded. No new highways in the works, but there are the lifetime jobs working on Rt28 or Rt22 if ya got the Guido hookup (hey, my cousin Guido needs a job, can he get in here?).

  • avatar
    netrun

    If a larger number of motorists simply followed their lead, stayed in the “open” lane to the bitter end and THEN alternate-merged into the funnel, everyone would get where they’re going more quickly.

    We often drive at a distance behind the vehicle ahead that far exceeds our ability to avoid a crash, because we have blind faith that the driver in front of us will never, ever need to stop quickly.

    This guy obviously has never actually driven a car before! The ‘jerks’ who are trying to cut in at the last moment cause most drivers to drive too close to the car in front of them. It’s a direct cause-effect relationship. Get rid of the ‘jerks’ and people will drive with a healthy gap to the car in front of them.

    I see this on a construction route I drive every day. When there is more traffic, and more ‘jerks’ trying to cut in at the last minute, people in the remaining lanes are literally within two feet of each other. When there is less traffic and the ‘jerk’ lane is empty, everybody reverts to a car length and a half to the car in front of them.

  • avatar
    pariah

    Discipline is the biggest factor in whether you’re a good driver or not. Look at it this way: when you passed your driver’s test, you demonstrated a thorough knowledge and understanding of the rules and laws of operating a motor vehicle on your state’s roadways. By signing your name on your license, you’ve made a written agreement to abide by those rules.

    The average driver certainly knows that they shouldn’t ride up half a car-length from a preceeding vehicle’s ass, or floor it when approaching an intersection, or drive 45 miles per hour through a 25 MPH residential street, but they do it anyway. Why? Well, the average person is also self-serving, lazy, and impatient.

    The best drivers in the world are the ones who possess the self-discipline to overcome these urges. You have to just realize that you are not more special than anyone or everyone else on the road, your wants are not more important, and you are not above the law just because you want to be. You can’t make excuses; you can’t make exceptions. The only way to be a truly good driver is to exercise discipline every day, all the time. Not to do so is to be weak-willed and a danger to everyone else on the road.

  • avatar
    Kevin

    Whenever I hear of a road rage incident where some driver shoots another, my first thought is always “Well I wonder if they deserved it?”

  • avatar
    thalter

    Happy coincidence, I am reading this book as well! I find it a gripping read, but if you are not an engineer (like me), you may find it a bit on the dry side. Covers everything from risk actualrialization to socialogy to game theory and Nash continuums.

    Highly recommended read for any serious pistonhead.

  • avatar
    MikeInCanada

    More and more I feel that seat belt (and motorcycle helmet) usage should be discouraged. Let Natural Selection help identify the best (smartest) drivers.

    They’ll be the ones wearing helmets and wearing seat belts, irregardless of the blinking red light on the dash says.

  • avatar
    kurtamaxxguy

    “Jerks will stay in the closing lane all the way to the end, then force their way in. As Vanderbilt correctly argues, these “jerks” actually help traffic move faster.”

    Really? Just drive any Calif Freeway between LA, SF and Sacramento during the holidays to watch this in action. Mucho hooligans going stir-crazy in the conga line to right of truck convoys _will_ cut out from left lane to right in front of truck, drag race convoy space up to next truck, then jam back into the left lane conga line, causing everyone there to slam on their brakes to accomidate “h”. Inevitably it’s a freeway closing accident or CHIPS barely missing you to chase ‘em.

  • avatar
    50merc

    “If a larger number of motorists simply followed their lead, stayed in the “open” lane to the bitter end and THEN alternate-merged into the funnel, everyone would get where they’re going more quickly.”

    Did the author base that on ivory-tower calculations (hence, bumblebees can’t fly) or empirical observations? My experience has been that late-merging “it’s all about me” drivers jam into the open lane at the last second, thereby causing consternation and “accordioning” of cars in line, and–often–collisions as those vehicles make panic stops. Of course, people in the open lane can be stupid too. Once I rode with a fellow who simply drove to the end of the closed lane, stopped and put on the turn signal. He explained, “Someone always stops and waves me to go ahead.” And sure enough, that’s what happens, thereby causing backups in the open lane.

    Some years ago Arkansas launched a massive road improvement program. They figured out how to keep traffic moving. As one approached a construction area there were signs for “no passing” and then “merge NOW.” In other words, signs to tell people to not be greedy idiots. Arkansas had so much success with that signage, Oklahoma (after dithering for years) adopted the method.

  • avatar
    Mike66Chryslers

    Allright, I am the jerk the runs up to the point of a merge. I dont do it because it actually helps traffic, I seriously doubt that it does. I do it because I refuse to sit there watching the traffic fly by and cut in at the last moment as I crawl up to the front.

    Perhaps if everyone did like the author suggested and alternated merges it would help traffic, but that never happens, and never will.

    I’ve driven in two places where people actually merge properly and exhibit other courteous driving behaviours: British Columbia and Germany. I don’t live in either of those places though.

    In my neck-of-the-woods the slow people tend to drive in the middle lane on the highway, causing impatient people to weave between the inside and outside lanes trying to get ahead. I’ve had somebody pull onto the highway from an onramp and directly into the middle lane in front of me, forcing me to slam on the brakes.

    What about the tendency for people to follow large vehicles more closely? If you can’t see around a vehicle to know what’s ahead, you’d think you’d want to drive FURTHER BACK.

    I drive a pickup truck with a cap and before that I drove a fullsize van, so I experience this all the time. What’s even worse is people that pull-up right on my tail, realize that they can’t see anything, and pass me. THEN they realize that they didn’t want to be driving that fast in the first place and slow down so now I am tailgating them. I drive with my cruise control on whenever possible, which makes this doubly annoying.

  • avatar
    Redbarchetta

    Is the guy in the Bug asking for a beer or a bottle opener for the beer in his lap? Love his fuzzy dice.

    I used to drive like the thetopdog until I got my motorcycle endorsement and took the MFS course. You become a lot more curtious and conscious of more dangers on the road when death is around every corner and you stop being a cager. You also learn to stay the hell away from most other drivers. I still drive fast though, can’t cure me of that, well in the car my wind hurts too much past 80mph on the motorcycle.

    I will admit I’m damn good at driving and making love, once at the same time. Is there a name for that, sort of like the mile high club?

  • avatar
    psarhjinian

    I will admit I’m damn good at driving and making love, once at the same time. Is there a name for that, sort of like the mile high club?

    The mile-long club?

  • avatar
    Dynamic88

    “If a larger number of motorists simply followed their lead, stayed in the “open” lane to the bitter end and THEN alternate-merged into the funnel, everyone would get where they’re going more quickly.”

    How much more quickly? 11 seconds? 48 seconds? 1.75 minutes? Tell me when we get to a meaningful number.

  • avatar
    pariah

    I used to drive like the thetopdog until I got my motorcycle endorsement and took the MFS course

    Similarly, I was, in hindsight, a terrible driver until I got my class A CDL. A lot changes about your perspective of driving when you send some time wheeling around a 13-speed 80,000-pound vehicle as opposed to something as effortless as a small one-ton car with an automatic tranny. The ease-of-use and mindlessness of a modern car seem to make people even worse drivers than they normally would be.

  • avatar
    fisher72

    Currently read this book, cannot embellish further.

  • avatar
    findude

    There are merges where I use the late merge technique for different reasons: courtesy and safety. This is an off ramp that does a 270 and then merges onto another highway. Keeping the merge lane full in congested conditions rather than merging earlier decreases the likelihood that cars 20 or 30 cars back (and not in view) will not be stuck in Interstate traffic begging to be rear-ended because the merge lane is backed up.

    I have tried in vain to explain this to people who fancy themselves “courteous” drivers. For them courtesy is about smiling and waving and excludes utilizing a system perspective to be courteous to other drivers who are out of view and will never directly observe your courtesy.

  • avatar
    rpn453

    Unfortunately, the six cars behind you each progressively uses up the rapidly closing gaps that you have single-handedly created, and the tenth car in line has a huge and unavoidable rear-ender that you caused.

    I strongly disagree. The guy who rear-ended the other car is the true cause of the collision. I am not responsible for the actions of the driver behind me. He should maintain a proper following distance, as should I. But if I don’t, it’s not my fault he didn’t either.

    There are only two possible “unavoidable” rear-enders that I can think of. One is caused by a freak mechanical failure. The other occurs when someone cuts you off and immediately slams on the brakes. Otherwise, you’re always at fault if you hit the person in front of you.

  • avatar
    Adamatari

    It’ll be easier to drive safely when people don’t actively block when you turn on the turn signal. Or block when you try to merge. It seems to me those situations lead to much of the driving waaaay too close issues – people open up one car length exactly, or 2 or 3 cars attempt to merge in front of one person… We really need better driver training. At least we aren’t India, though.

    Another ironic thing: people drive closer in the rain, but slower. It’s not going to help much if they have to make a sudden stop.

    Eh, I admit that I’m not the greatest driver. I try to be safe, but I’m not perfect. I’ve had my share of near misses, a few from my own stupidity, and so over the years I’ve gotten more and more cautious.

  • avatar
    cgd

    I’m intrigued and want to read this book. For years I’ve been wishing for one day, just ONE day, where I can drive to work and back home (14 miles each way) with not one incident of any moron pulling in front of me, cutting in front of me on the interstate, or otherwise being discourteous, reckless, and dangerous. But that one day hasn’t happened in several years.

  • avatar
    Phu

    Thank you for giving us a much needed break from domestic manufacturer meltdown related editorials. But I still don’t understand how that “jerk” causes the line to move quicker. One would figure he slows the car that let him in which in turn magnifies that w/the cars following it.

  • avatar
    shaker

    Just reading the synopsis presented here makes me think that a “Cliff Notes” version should be required reading in preparation for driver’s tests nationwide.

    The merger issue was (sort of) addressed in PA by signs reading “USE BOTH LANES TO MERGE POINT”. Apparently, this is too cryptic for many drivers, or there is an alternate explanation:

    If you stay in the left lane to the merge point, you normally have to “request” that the person in the right lane allow you to merge (by using your turn signal), and to acknowledge the “favor” of them letting you merge with a wave, a smile or whatever.

    If you are in the right lane, the situation is reversed, and you get the chance to be the magnanimous benefactor to the “jerk” in the left lane.

    Which would you rather be?

    Thus, more real estate taken by the “good guys”.

  • avatar
    kc2glox

    Here’s a technique I have used occasionally to cope with the long backed up merge situation. I’ll stay in the merge lane alongside a semi and let traffic clear in front of me. Infuriating the jerks in the merge lane behind me. The pay off is after a few minutes the through lane starts moving (presumably after the inconsiderate drivers clear through). Then both lanes start moving smoothly. I have done this twice on two different I-40 Tunnels that were shut down to one lane in the Carolina’s with the exact same Semi Truck. Truck Driver Dude Loved it both times. I’ve seen Semi’s do the same thing. It helps to go ahead and flip the rearview mirror to dim, and be prepared for some easily ignored behaviors behind you. I always wander if the drivers that were “delayed” behind me realize what affect their behavior has on traffic overall. Given their reaction as they pass, probably not.

  • avatar
    beetlebug

    However, you do gotta admit that Oaktree Corner at VIR is damn hard.

  • avatar
    dragoniv

    For those of you who doubt the effectiveness of merging at the last possible moment, rather than merging “nice” at the first sign of lane closure, try out this simple example.

    The road in question is four miles long, and normally three lanes wide. Construction has limited it to two lanes for a one mile stretch, but notices for the lane closure stretch out a mile before the closure.

    All other things being equal, you will fit more cars per hour down the expressway where the lane closure is limited to one mile and not two. Try it out with Matchbox cars sometime.

    Now, add the combination of self-righteous lane blockers and anarchist lane jumpers, and yeah, with enough thrashing, it can erase any difference between the two approaches. I still merge at the latest possible point, mostly to see just how crazy people will get to “defend their turf.”

  • avatar
    Stephan Wilkinson

    The first poster on this thread asked that if we do book reviews–which I don’t see happening with any frequency–we include title, author, publisher, price and all that stuff.

    That seems to be a little old-fashioned these days, and I hope that everybody understands that all you need to do is go to amazon.com or bandn.com (Barnes and Noble) and type “traffic” or “tom vanderbilt” into the search box and you’ll near-instantly have everything you need to know about the book and then some.

    As for commenters who take issue with the author’s opinions, I would hope they at least read the book–your local library is sure to have access to a copy from its library network–before becoming set in their opinion based solely on an 800-word review.

  • avatar
    charleywhiskey

    Yep, same doggone thing happens to me every time I have to avoid a zebra in Maine.

  • avatar
    mdf

    Stephan Wilkinson: As for commenters who take issue with the author’s opinions [...]

    Well, do recall Mr. Wilkinson, that you explicitly agreed with the “opinions” at points in your review. (“As Vanderbilt correctly argues [...]“).

    Can you further describe the “correct” arguments made? I too would be interested to know just how appeasing the “jerks” makes things go faster, especially when the “non-jerks” have to slow down an entire lane of vehicles in order to do so.

    Was it a hand-waving argument, or based on actual observation, experiments or plausible simulation?

    dragoniv: All other things being equal, you will fit more cars per hour down the expressway where the lane closure is limited to one mile and not two.

    In the steady-state, the number of cars per hour would have to remain the same, no? Otherwise, the backup would increase in size without bound.

    I still merge at the latest possible point, mostly to see just how crazy people will get to “defend their turf.”

    I have a strong bias to “defend the turf”, simply because the “jerk” is only one, while there are N (N >> 1) “non-jerks” behind me. Said “jerk” had lots of time to join the line, and chose not to. He made his bed; why should he be denied the opportunity to lie in it?

    Again, I’d like to see the details of the argument, since like others here, I have watched this kind of situation enough to get a sense that individual strategy doesn’t matter much in the aggregate.

  • avatar
    menno

    Assuming you were serious, pariah, I have to say “bravo” for your comments, which bear quoting and repeating.

    “Discipline is the biggest factor in whether you’re a good driver or not. Look at it this way: when you passed your driver’s test, you demonstrated a thorough knowledge and understanding of the rules and laws of operating a motor vehicle on your state’s roadways. By signing your name on your license, you’ve made a written agreement to abide by those rules.

    The average driver certainly knows that they shouldn’t ride up half a car-length from a preceeding vehicle’s ass, or floor it when approaching an intersection, or drive 45 miles per hour through a 25 MPH residential street, but they do it anyway. Why? Well, the average person is also self-serving, lazy, and impatient.

    The best drivers in the world are the ones who possess the self-discipline to overcome these urges. You have to just realize that you are not more special than anyone or everyone else on the road, your wants are not more important, and you are not above the law just because you want to be. You can’t make excuses; you can’t make exceptions. The only way to be a truly good driver is to exercise discipline every day, all the time. Not to do so is to be weak-willed and a danger to everyone else on the road.”

  • avatar
    Robstar

    My wife & I drive vastly different and it is completely cultural. Is this book solely US focused?

    Since I drive stick and my wife does not, I often drive when we need to drive in Brazil. She gives directions for me (in English) in her home city.

    I still drive her nuts, as I slow down when I see kids playing in the street, people crossing without much clearance before my car gets there etc. I stop completely at red lights at night.

    My wife does none of these things, as slowing unless you absolutely have to (stopped traffic in front of you) opens you to carjacking/robbery, as does stopping at red lights. Driving NOT like a Brazilian points to you being a foreigner and people taking an interest in you, which you absolutely do not want (they assume most foreigners have money…surprise, eh?) She always is freaking out when I drive in her city.

    On the reverse, here, she drives very cautiously and has adapted….although she still doesn’t use her mirrors properly (only 3 years experience) and has been in 1 accident (not her fault, but IMHO she could have avoided it driving more defensively). She also does not like me letting me wave to people at stop signs to go first, or letting people in at merge points.

    Having driven a motorcycle for 3 years, I TRUST NOBODY which is why I almost always yield. Any tie at a stopsign goes to the other drive. It drives my wife NUTS when I’m in a car and I also yield the same way but it has been habit.

    I turn 33 next month and my last accident was just after I turned 19.

  • avatar
    Stephan Wilkinson

    mdf: RTFB.

  • avatar
    Stephan Wilkinson

    Robstar: definitely not just U.S.-focused. The author traveled to, and drove in, everywhere from the Netherlands to New Delhi. Certainly much of it concerns U. S. drivers, but there’s lots of interesting material about how traffic is regulated, and how drivers drive, in other countries as well.

  • avatar
    dragoniv

    mdf: I did not say steady-state. :)

    Let’s simply this further. Take two lanes, similar setup as before. No lane closure, you can fit 6,000 cars / hour / lane through this four mile ride, 12,000 cars / hour total. Now assume that during rush hour, you’re close to this 12,000 cars / hour limit.

    Take a lane and close it for one mile. Neglecting the cost of merging and a speed limit change in the closure area, you now only can get 7/8ths of the traffic through, because 1/8th of your total traffic lanes are closed. So, your throughput is 10,500 cars / hour now, if they are merging at the point of closure.

    Now, instead, have people merge at the warnings–you’re now effectively closing the lane for an extra mile. Throughput is now 9,000 cars / hour. See? Less throughput, so it takes longer to get home this way.

    Now, you can say “hey, what about the cost of merging,” but you’re doing the same merge in both examples. Contribution should be approximately the same.

    Does this offer anyone a faster trip home? It wouldn’t, if people used the first system consistently. Having no free space in that lane won’t allow a drastic change in flow between the lanes.

  • avatar
    rpn453

    That is a good quote, menno. Well said, pariah!

  • avatar
    miked

    dragoniv: There’s a difference between number of cars you can fit on the road and number of cars that pass a certain point. The length of the lane closure has minimal effect on the throughput. It’s easy to see if I do a reductio ad absurdum agument, but it’s still valid in the real world.

    Let’s say we have a two lane road with a very high traffic density (say 12,000 cars/hour like you used). We merge that down to 1 lane and at the end of the lane is a demon who sits and lets only 1 car through each minute. No matter how you do that merge, the rate limiting step here is that demon who has brought the traffic flux down to 60 cars/hour. No car can proceed until the demon says it can go. So the whole road is slowed down to 60 cars/hour.

    Back to your example. If each lane can support 6,000 cars/hour, then the closure down to 1 lane means that at best 6,000 cars/hour can get through, no matter if that closure is 10 feet long or 10 miles long.

    The problem is that the merge time/merge cost, is usually more than we think and the rate-limiting step is the actual merge, not the lane throughput. Ever notice that when you’re stuck at a merge, once you make the merge you end up speeding up again? To put numbers on it, say we have 6,000/cars/hour/lane and we go from two lanes to one lane. If we can merge at a rate faster than 6,000/cars/hour, the only slow down we’ll encounter is the 12,000 -> 6,000 cars/hour. But as is usual, the merge is painful and slow, and we may only be able to get 1,000 cars/hour at the point of merge. So now that we’ve merged and we’re at 1 lane, we can go faster because the lane is under utilized, since only 1,000 cars/hour are now using it. The merge is what caused the problem.

    You can only count cars/hour that pass a fixed point. That’s why your previous example of closing a lane for only 1 mile or 2 miles isn’t quite right. So until people can merge as fast as they can pass through the only open lane, the best place to focus your efforts is in efficient merging.

  • avatar
    Victell

    Traffic should be like water and flow where it fits. Merge lanes work best when they are full all the way up to the physical merge point, then come together like a zipper – one to one.

    Road engineers usually have a reason for the designed merge lane length, and they plan for cars to actually use it for that length. It only makes sense that the number of car not in a merge lane are the cars that make the non-merge lane(s) that much longer. I have seen situations where cars get out of the merge lane too soon and back up traffic to the point where there is gridlock at an intersection a few hundred feet back. If those same cars filled the merge lane traffic would not back up as far, and the intersection would be clear – as traffic engineers have planned and set the traffic signals for.

    But for some reason a lot of people love to get in lines, and as soon as possible. I have no idea why this is. I have seen it at the DMV and other places. Most people automatically believe they should be in the longest line, and without thinking go straight there.

    TTAC is a car site, which I thought attracted not only car enthusiasts but also driving enthusiasts. There are a surprising number of folks here who seem to want to queue asap, and then get upset at others who choose not to.

  • avatar
    Stephan Wilkinson

    Victell gets it.

  • avatar
    Dynamic88

    Has anyone ever seen the merge lane open ?

    What I usually see is both lanes completely full to the merge point, traffic crawling. People merge before the end because they know they have to merge anyway. When traffic is crawling it doesn’t feel like you’re slowing anyone down by merging sooner rather than later.

    I ask again, how much time do we save by waiting until the last moment to merge? Do I get home in time to watch an entire TV show?, or just catch the end of it? Are we talking a half an hour, or 3 minutes?

  • avatar
    mdf

    Victell: There are a surprising number of folks here who seem to want to queue asap, and then get upset at others who choose not to.

    People merge as soon as possible for the same reason why they get a job as soon as possible, instead of waiting for the bank account to drop to zero.

    And they get upset at pushy last-instant mergers for the same reason why most people feel little sympathy for those who didn’t look for a job, and are now in-your-face begging for hand-outs.

    Furthermore, I can say that I love driving: open road, scenery, the machine, the whole thing. Merging, however, is not driving. It is a boring experience. It’s like brushing your teeth, or wiping your ass: necessary functions, but completely uninteresting, time taken away from playing with children or programming the computer … or driving the car! As soon as someone makes a robot that can drive, I’ll buy one and give it this tedious grunge-work.

    As for your argument, though: like dragoniv, I think you confuse space with flow. Recall that the central position in debate is that merging at the last instant results in “traffic moving faster”, not simply more cars on the road. In the situation you outline, the merge lane is little more than a glorified parking lane. However, this raises an interesting question: is the optimal flow-rate strategy to allow mergers to push their way into traffic (slowing it down), or to simply force them to wait for traffic to clear and then letting them un-zipping safely from back to front? My guess (lacking formal simulation testing, but based on daily experience) is that it simply doesn’t matter from a global perspective.

    Now, people blocking intersections need to be told not to do that, and if they persist, dragged from their vehicles and whipped mercilessly. However, this is true whether or not merge lanes are filled according to the Original Intent of the Founding Fathers of the Road.

    I should also point out that water flow and traffic flow aren’t really the same beast. Consider: fluid flow will be faster through a choke point in order to maintain the same mass rate. Has this _ever_ happened on any road?

    Dynamic88: Has anyone ever seen the merge lane open?

    Actually, yes, this is quite common (or at least I witness it daily). For at least two reasons:

    1) people know from experience they are farked if they are stuck in the merge lane: few will let them in, especially if you, the merger, are stopped dead at the merge point. The slightest hint of lane-ending is going to get them to move, and pronto.

    2) Related to (1), and the reason you give: people, rationally, look down the highway and see the inevitable, and then make their move at what they feel is the appropriate time.

    In effect, the merge point is not fixed in space, but variable. As density increases, and traffic slows, the location of the merge point becomes unimportant, and a few holes here and there into which a car or five can be shoved almost irrelevant.

  • avatar
    Stephan Wilkinson

    In fact, as the book “Traffic” points out, traffic acts like grains of rice, not water. If you take a funnel and dump an entire pound of rice into it, the rice will stream out relatively slowly, since there’s a certain cohesiveness and interference between the grains in the body of the funnel. If you pour the rice into the funnel relatively slowly, the rice will stream out somewhat faster.

  • avatar
    ktm

    Well said Victell. There is a reason why people are referred to as “sheeple”.

  • avatar
    Andy D

    I was working in Boston today. During one of my trips out to my truck, this clown was taking issue with being grid locked on a side street by a bus. He was leaning on his horn. Seconds passed. As I walked by him, I said that his honking was really helping the situation. He stopped.

  • avatar

    I grew up in a small town in the Maritimes. I learned defensive driving and all that jazz. Traffic jams in my hometown were when there was no empty space between two sets of lights.

    Then I moved to Montreal.

    All my prior training as a good driver went out the window, and I’m all the better for it. People complain about MTL drivers all the time, but if you are capable of paying attention to your surroundings you really become a much better driver. You have to be aggressive, quick acting and merciless otherwise you’ll be (at best) the asshole who holds up downtown traffic, or (at worst) the moron in a now-wrecked car blocking the freeway. This requires concentration, something entirely lacking among most drivers, especially outside big cities. Throw some bumpkin onto the Decarie expressway at peak flow with semis grazing their doors at 130 km/h and see how they fare (actually I see it daily, they are the nitwits who plug up the flow of traffic all the time). I even get pissed off when I drive through Toronto because the people are either negligent or overly conscious of other drivers (stopping to let people pull out of t-junctions in busy downtown traffic – courtesy has a place, but not when it involves holding up commuter traffic in a multi-million pop city)

    Step one to improving traffic behaviour – rewrite “defensive driving” techniques or toss them out altogether. Step two, ban automatics so people actually pay attention to the task of driving their vehicle. Step three, have final driver training on the streets and freeways of Montreal during peak traffic and rush hour. When I come to power as a benevolent dictator, these will be the first orders to the transport department, right after abolishing speed limits outside of residential areas.

  • avatar
    blkstne

    I hate when drivers seem to be afraid to accelerate into traffic (be it merge lane, on-ramps etc). Than once in traffic they creep along causing all traffic behind them to slow up. One should always drive at or faster than the surrounding traffic speed that one is merging into. There is nothing worse than a person driving from a on-ramp or a another lane and I have to hit my brakes because they are driving 20 mph slower than the other fifty cars around them.

    I myself love speeding up on-ramps and merging into traffic already doing 60-70 mph.
    I have driven in about 6 different countries and all over the United States.
    The best drivers adapt to the surrounding traffic they are driving in at that moment.


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