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Maintaining a safe following distance is incredibly challenging on busy freeways where hard braking is often 'required'. Most people have likely found themselve

Maintaining a safe following distance is incredibly challenging on busy freeways where hard braking is often 'required'. Most people have likely found themselves in this situation: vehicle changes lanes in front of you; you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. Incredibly frustrating, and I've driven all over North America - there's practically no major city where this doesn't happen. If you're not maintaining a safe following distance on city/residential streets, that's a different matter.

amanaplanacanal 8mo ago
Does it really matter though? Is the end result just a couple of minutes later in a 30 minute commute? Or does it actually make a large difference in travel time?
- mountain_peak 8mo ago
  It used to be more of an issue when I was younger. Now that I'm older and more 'seasoned' (plus reflexes do slow down), I'm far more patient and have no issue maintaining a healthy following distance. I think the statistics reflect this in age vs. accident rate as well. Unfortunately, sometimes over a 45 minute freeway commute, dropping back repeatedly means arriving 15 minutes or more later. Again, no big deal now, but it was somehow unacceptable when I was younger.
  - Noumenon72 8mo ago
    For your commute to take 4/3 the time, you would have to be averaging 3/4 the speed -- going 45 in a 60. That doesn't make sense because even going 55 would mean traffic pulled away from you rather than you having to drop back from it. Going 55/60ths the speed means you arrive in 60/55ths the time, or an extra 4 minutes on a 45 minute commute.
- yial 8mo ago
  It doesn’t - but people don’t necessarily make rational choices regarding speed and driving. There’s a tendency to de personalize other drivers. A slight increase in average speed really only makes a significant difference over long drives. (5 mph increase over a 10 hour drive can cut off 50 minutes). Otherwise we are talking about small differences in efficiency. (I would be very open to another opinion here.). My opinions are formed by nearly ~2 million miles driven at this point, two different driving courses, and the motorcycle safety course. One thing I truly think that’s overlooked is how reduced road noise in the vehicle cabin can both reduce driver fatigue, but also frustration in traffic.
  - badc0ffee 8mo ago
    > (5 mph increase over a 10 hour drive can cut off 50 minutes) You can't really say that without knowing the starting speed, or alternatively the distance. All you can say is that a 5 mph increase over a 10 hour drive with get you 50 miles farther.
    - yial 8mo ago
      I would argue I can still say it /can/ cut off 50 minutes. If you do a comparison of a 600 mile trip at 60 vs 55 you’re pretty close. But yes, to be pedantic and more exact, you are spot on that it will get you 50 miles closer. But in real world examples, If you’re traveling 700 miles. 65 vs 70, 70 will reduce your time by 43 minutes. So in certain scenarios, 5 mph difference must be able to save you 50 minutes ! ;) (I do understand your point, and you’re correct. I’m just poking fun at it- my point with the mph difference is because 50 miles doesn’t have the same translation for most people at 50 minutes, but is a more accurate data approach. )
      - badc0ffee 8mo ago
        > So in certain scenarios, 5 mph difference must be able to save you 50 minutes ! ;) That is true. If you're going 55 mph for 10 hours, you'll go 550 miles. Increase your speed to 60 mph, and you'll get there at 9 hours 10 minutes.
  - 8mo ago
- avidiax 8mo ago
  > Is the end result just a couple of minutes later in a 30 minute commute? More like a few seconds. Every car that merges in front of you only costs you their following distance. If the average following distance is 1 second, then you are simply 1 second slower than you'd have otherwise been. So unless this is happening continuously every 30 seconds on your 30 minute commute, you will lose less than a minute. The "but if I kept reasonable following distance, people will keep merging in front of me and I'll lose time" excuse is pretty thin given this analysis. And an insurance claim can easily eat 40 hours of time between the insurance companies, other lawyers, buying a new car, medical appointments and recovery. That's 19,200 minutes you won't get back, or about 52 years of driving 1 minute slower each day. Slow is smooth and smooth is fast.
- cucumber3732842 8mo ago
  I have been doing the same commute at the same time for the better part of a decade. At this point I can look at my watch and tell if I'm ahead of schedule or behind schedule and infer what the compounding effect will be later in my commute. I can easily shave 10% off my commute by lane changing to avoid the lanes where turn lane traffic tends to back up into the travel lanes, ramp traffic and "problem people". I test the null hypothesis several times a month by carrying bulky topheavy cargo that precludes a bunch of lane changing without more effort than I want to put in. I don't think there's much to be gained by simply lane changing to chase fleeting gaps in traffic. The wins and losses will probably mostly cancel out.
yial 8mo ago
This is accurate in many ways. I use the auto cruise feature on my car frequently and I notice several things happen unless I set the distance as close as possible (which I don’t like to do. ). 1. In any amount of traffic above “a few cars” people will cut in front of me, sometimes two, negating the safe following distance. Regardless of speed. 2. If I have a safe following distance while waiting for someone to get over. (I e they’re going 60, I want to go 70), if I have my distance set at a safe following distance, people are much more likely to weave / pass on the right. (My theory would be that the distance I’m behind the person in front of them signals that I’m not going to accelerate / pass when the person gets over ). Disclaimer: I don’t usually have to drive in any significant traffic, and when I do (Philly, New York City), I’m probably less likely to use the automatic features because the appropriate follow distance seems to increase the rage of drivers around me.
- VladVladikoff 8mo ago
  Just drive in the slow lane and you won’t have this problem. The people cutting in front of you rarely want to be in the slow lane.
  - yial 8mo ago
    I do drive in the slow lane frequently - and this still occurs. (My go to is to set my cruise 6-9 mph over the speed limit, if passing to smoothly pass and get back over, and spend as much time as possible in the slow lane. ) However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.
    - girvo 8mo ago
      The idea of cruising 15km/h over the limit is absolutely crazy to me. That will get you 3 points and a minimum $500 fine here. We have "average speed zones" too!
      - fredophile 8mo ago
ChuckMcM 8mo ago
Okay I'm thinking of a very Shenzen kind of gizmo for your car that projects a bright red laser "keep out" box on the road in front of your car which is adjusted in size for your current speed.
- NitpickLawyer 8mo ago
  We have something like that in eu with road markings. Both for clear weather and fog/rain. They mark some of the lines differently, and tell you how many lines you should have between you and the car in front. I think they were first trialed and then printed in several places.
  - ChuckMcM 8mo ago
    Cool. But I'm thinking this box floats in front of your car on the road in real time. See you're driving and ahead of you on the road is this box. At night it might interfere with your night vision, might have to workshop that a bit.
  - ErroneousBosh 8mo ago
    There's a couple of bits of motorway in England with that, I'm pretty sure the M6 and the M1. There are white chevrons painted on the road and you keep two of them between you and the car in front. Also "Keep Two Chevrons Apart" is going to be the name of my specialist Citroën breaker's yard.
    - ninalanyon 8mo ago
      And on the M5 between Gloucester and Bristol.
- rootusrootus 8mo ago
  I think a lot of people would just consider that a challenge. On the occasion when I am towing our travel trailer, it is really incredible how unsafe that makes other drivers act around me. They will jam themselves in front of me at all costs, with no consideration for physics.
duped 8mo ago
Why does this require "hard" braking? If another car cuts in front of you just decelerate gently. You don't brake and wait until the gap is big enough (also if this is stop-and-go traffic, you should be trying to avoid braking at all)
- mountain_peak 8mo ago
  My original observation wasn't worded as well as it could have been. I meant in situations where hard braking could be required on a moment's notice for no particular reason (e.g. Chicago freeways where everyone is doing 70 mph bumper-to-bumper and decreases to 10 mph all of a sudden). Indeed, when someone changes lanes in front of me, I gently let off the accelerator, but as someone else noticed, that can enrage drivers behind me (I don't take it personally), and I'm definitely traveling fast enough to remain in the middle lanes.
sagarm 8mo ago
If you think highway driving requires hard braking, you're a bad driver.
- appreciatorBus 8mo ago
  Yes. If people are constantly moving into your appropriate head way this is doubtless annoying but the correct response is allow yourself to decelerate slowly to re-open that space again, repeat as many times as necessary, even if it means a bunch of agros end up in front of you. Better for them to be in front where you can see them, than behind or to the side, were you can't.
  - mlyle 8mo ago
    Yah. There's something that feels unjust about it -- the perception that the people cutting are getting something over on you -- that causes us to want to behave badly. But even if 2 dozen people go around you and creep into that following space, you've been cost like 45 seconds at worst. Better not to play the game.
    - cmurf 8mo ago
      They are likely getting more frequent brake pad replacements. Not a significant cost. But they sure as shit aren't getting what they think they're getting. Meaningfully farther ahead. I now see it all as a risk assessment rather than as ritualistic combat.
      - its_magic 8mo ago
        If you added a missile launcher to your vehicle, it could become ritualistic combat again.
    - ryandrake 8mo ago
      Society would have a lot fewer car accidents if we, collectively, could get over that "Oh no someone dared to get in front of me!" feeling.
kube-system 8mo ago
If you think people are going to cut in front of you, provide a safety cushion large enough to account for that. Aggressive drivers almost universally will consume the forward part of the space cushion you leave. At most you will simply need to lift the accelerator to maintain space. The only time someone cutting in front of you should require hard braking is if they also brake hard. It does require patience to do this, because all aggressive drivers will use the space you provide. But ultimately the travel time difference in flowing traffic is negligible.
- MostlyStable 8mo ago
  I'm not sure it's that negligible. Mythbusters found that weaving in and out of traffic could save between 5 and twenty-five percent. Now A) Mythbusters did an experiment with an N of like 4 or something, along a single commute in the Bay Area, so it's basically anecdote and I'd love a better source if one existed, but it is at the very least proof-by-existence that larger impacts on travel time _can_ happen. And their non-weaving person was, if I recall from the video, not constantly decelerating to keep a buffer. And from personal experience in some places, keeping such a buffer, in some traffic conditions would just literally be impossible. There are sometimes enough aggressive drivers such that they can just consume it faster than one would be able to create it. It is simply not always the case that you have sole power to create and keep the recommended buffer size (although very often it is and you can). I keep a decent buffer whenever I am able, but at some point, you have to bow to road conditions.
  - streetfighter64 8mo ago
    25% of time saved corresponds to increasing your average speed by 1/(1-0.25)=33%, for example from 45 to 60.
- cucumber3732842 8mo ago
  Letting a large fraction of the freeway cut in front of you will turn normal drivers behind you aggressive, or at least aggressive enough to go around you. There's a balance to be struck.
bluGill 8mo ago
False. I've done it many times - when you open up space two cars jump in, but the rest don't and so the space remains. But you notice those two cars and think it means more than it does.
OptionOfT 8mo ago
> North America Having driven all over NA, and Europe, I find it more prevalent in NA. Less distance, more people in large pickups throwing their weight around to make someone move out of the way. And a design of giant freeway interchanges that require shifting lanes. E.g. on the 405 in CA. 7 lines going South from the Valley towards Santa Monica. That's 7 lanes you need to cross if you're in the HOV lane.
- ChoGGi 8mo ago
  > That's 7 lanes you need to cross if you're in the HOV lane. The 401 is my favourite with eighteen lanes, four for the inner express lanes, and five for the collector lanes. https://en.wikipedia.org/wiki/Ontario_Highway_401#/media/File%3AHighway_401_cropped.png https://en.wikipedia.org/wiki/Ontario_Highway_401#/media/Fil...
- vincston 8mo ago
  Honestly imo the driving license requirements and the respective fines for violations is too low. Rigid rules generally improve the traffic flow. But as soon as someone just doesnt care, the system breaks down.
gwbas1c 8mo ago
I'm one of the faster drivers and I maintain a safe distance. (I usually have the most distance in rush hour.) It's very easy with adaptive cruise control or the other self-driving technologies that are on the market. The only people who cut too close to me are driving recklessly. That being said: If you're in the mode where people are constantly changing lanes in front of you, think a bit about how you're driving: On the freeway you're supposed to stay to the right except to pass, and you're expected to keep up with the flow of traffic. Are you going slow in the left lane? Are you driving too slow? Are you camping in the right lane by a busy interchange?
- thewebguyd 8mo ago
  > and you're expected to keep up with the flow of traffic. This is very state dependent, if we are talking about legality. In WA state, for example, there is no "flow of traffic" law or similar. The limit is the limit, and any excess of the speed limit is illegal regardless of what all other drivers are doing. So even if the right/slow lane is going 100MPH through the 70MPH zone, you are legally expected to still go 70. Thankfully we do have laws against left lane camping, but I rarely see it enforced.
  - Dylan16807 8mo ago
    > This is very state dependent, if we are talking about legality. Are you sure? And by that I mean, are you sure there are states that don't work the way WA works?
  - skue 8mo ago
    You’re confused. If you know of ANY US state that has a flow of traffic law that allows cars to exceed the speed limit so long as they are keeping up with other traffic, I’d love to see a link to their traffic codes. Speeding doesn’t suddenly become legal because two or more drivers do it together. This has nothing to do with the expectation that slower traffic stay in the rightmost lanes, which is what GP is addressing.
    - gwbas1c 8mo ago
sershe 8mo ago
The most frustrated people are those behind you, and if I was id soon be another person merging in front of you. If people are constantly merging in front of you, either everyone is going too fast or you are going too slow :)
Gravityloss 8mo ago
I live in a place that has harsh winter conditions with ice, gravel and the occasional loose tire stud flying into people's windshields, warranting frequent expensive replacements. Somebody on the radio said that "just set the adaptive cruise control to max distance and your windshield will last way longer". It does feel overprotective at times, especially in slow and dense traffic, but I think there's a nice point in general.
- stevage 8mo ago
  Wow, I didn't know that was a thing. Been driving nearly 30 years, and never had a windshield chip.
  - its_magic 8mo ago
    Do you have a wood surface nearby? I would recommend giving it a good knock.
    - stevage 8mo ago
      Apparently I just live in a place where it's not a common problem. Also I do tend to leave a big gap behind cars in front.
      - ChoGGi 8mo ago
        They salt your roads, or put grit?
        stevage 8mo ago
        They don't do either of those things, and yet somehow I haven't witnessed any cars sliding off the road in winter either.
        its_magic 8mo ago
        From everything you've said so far, it sounds like people in your area have a lot of sense.
bloomingeek 8mo ago
Tailgating is against the law. Tailgating causes hard braking. I recently pulled my travel trailer from OK to Charleston, SC and back. I never drive over 65 MPH for safety and MPG reasons. I always stay in the right hand, slow lane except if I have to take a left lane exit. Since I was always driving slower then everyone else, not once did I have to hard brake. Tailgating is a choice and a dangerous one. I was never honked at, even by the crazy semi truck drivers.
- rconti 8mo ago
  Even that can be tricky, with the indecisive behavior people use when merging.
  - tadfisher 8mo ago
    That one's easy: leave space in front of you for those merging onto the highway. So much of road etiquette boils down to leaving adequate space so others can maneuver around you. Trying to optimize your travel by destroying any gaps as soon as they appear actually has the opposite effect.
    - HPsquared 8mo ago
      James May calls this "Christian motoring". Golden Rule etc
    - dekhn 8mo ago
      While leaving space is nice, the person on the highway already typically has right-of-way.
    - rconti 8mo ago
      It's really not. I drive at an upper-percentile pace, so I am rarely dawdling along in the right lane. However, on the rare occasion I've found myself going slowly in the right lane, it's stunning how incompetent most people are at merging. It's like they don't even consider looking for an opening in traffic, matching the freeway speed, etc. They just lumber in front of you at 43mph, and maybe, if you're lucky, look in their mirrors after they've already caused you to slow for them.
rconti 8mo ago
I find it quite easy to hold/manage a tight space that people won't cut into, and don't have to brake hard, because I look ahead. To be sure, it's more mentally taxing to hold a tight gap, so it's not something you want to do all the time, but it's fine.
trgn 8mo ago
> another car sees a gap and changes lanes in front of you. it's largely a problem in the left lanes, thats where drivers will bunch up most. the subjective feeling is mostly a reptile brain issue though, the feeling you're getting done over. driving is 90% id, sadly.
Sohcahtoa82 8mo ago
> vehicle changes lanes in front of you; I will never understand why this is so rage-inducing for people. Changing lanes is a necessary part of navigating, even during busy traffic. People on an on-ramp will need to get in front of somebody. People needing to move back to the right because their exist is coming up will need to get in front of somebody. Your lane is not a birth right. Let people merge. > you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. This happens because literally everyone is tailgating each other so hard that the gap in front of you is the only gap that exists for people to change lanes to either get on or off the highway.
- loeg 8mo ago
  It's frustrating when it eats into your safe following distance. The driver merging in ahead of you is being dangerous and not leaving a safe following distance for themselves (or you).
  - Sohcahtoa82 8mo ago
    When traffic is heavy, everyone is likely following at [what they perceive to be] a minimum following distance. It's simply not possible to merge during heavy traffic without eating into someone's safe following distance.
  - MPSimmons 8mo ago
    The buffer exists to be used. Allowing people to merge into it makes the lane that they came from safer. Build a new buffer.
  - idiotsecant 8mo ago
    It takes almost no effort to restore your safe distance again.
  - ndsipa_pomu 8mo ago
    What's the problem with reducing speed and reclaiming a safe following distance?
Dylan16807 8mo ago
I admit that I probably don't leave as much space as recommended, but I leave a good amount of space to never need to hard brake, and people don't keep moving in front of me either.
bsder 8mo ago
Maintaining a following distance is going to be one of the things that improves dramatically once self driving cars are widespread. Self-driving cars simply don't care that someone cut them off, they'll just happily open up extra space again and again.
- ninalanyon 8mo ago
  You don't need self driving, just traffic aware cruise control. Pretty much every modern car can have this as most now come with automatic emergency breaking and the same sensors can be used.
Izikiel43 8mo ago
> Maintaining a safe following distance is incredibly challenging on busy freeways I just put adaptive cruise control on max distance and call it a day, gives me 4/5s to react, and also it starts beeping hard if intervention is required. It has saved my bacon a couple of times.
singingbard 8mo ago
I actually disagree. People only take your lane if you are in the fastest lane. If you are in any slower lane, people tend to jump in and then leave and I have no problem with people who do that. You can also keep a gap in the fastest lane but you need to keep track of other cars on the road. You’ll observe that most cars rarely leave their lane. People who tend to leave their lane keep smaller gaps in front of them. Use that knowledge. There are many more factors than just that but if you start observing everyone drive, your little simulation in your head will start putting other drivers into buckets.
- bcraven 8mo ago
  These comments make me grateful that we have the concept of 'lane discipline' in the UK. It's rare to see the 'fastest' lane be anything other than the outside one. Otherwise we keep left and out of the way. https://www.highwaycodeuk.co.uk/lane-discipline.html https://www.highwaycodeuk.co.uk/lane-discipline.html
apparent 8mo ago
Totally. People will just cut you off repeatedly, which puts you (and the cars behind you) in a less-safe situation than if you followed more closely.
- ninalanyon 8mo ago
  > puts you (and the cars behind you) in a less-safe situation than if you followed more closely. Really? All you have to do is lift your right foot very gently until you have the expected spacing again, no need to sudden changes of speed and if you have traffic aware cruise control it will be done for you. My old Tesla S does it pretty well. I keep it set to three second spacing and when someone cuts in front my car just gently slows down until the spacing is correct again; it doesn't brake unless the car that cuts in is very close.
  - apparent 8mo ago
    Yeah totally works like that, until you get cut off 10 seconds later by another car. If this doesn't happen to you, then you're probably driving like I do, and not leaving 3 seconds of follow distance like they teach in driver's ed.
    - ninalanyon 8mo ago
      I do keep three seconds separation most of the time. If possible I engage traffic aware cruise control set to maximum separation for just that purpose. People do cut in but not often; what would be the point of cutting in between two vehicles that are both going slower than your desired speed? Also perhaps I should have made it clear that I am in Europe where one is expected and required to drive in the outermost (rightmost except in UK and Ireland) lane unless overtaking so the only time anyone would 'cut in' between my car and the one in front is when they are entering a motorway.
whitexn--g28h 8mo ago
This almost always happens when you are in the passing lane, and you are not passing. It’s much more rare in the right lane. Mythbusters, and also other traffic studies, show that returning to the right lane on the freeway whenever possible adds almost no time to a trip.
patcon 8mo ago
gah YES. I had a slow realization that I could just let people jump in. My goal is to maintain a constant speed and never have to hit the brakes, and I can usually still do that regardless of whether people jump line. But yes, the principle of it is incredibly aggravating ("that space is for safety, not YOU, green Acura!!!") but I actually kinda like the practice of trying to be zen about it. I mostly get through a long trip at the same rate :)
- RupertSalt 8mo ago
  Woah, like, "green Acura"? Where are you driving that you ever see one of those? In the USA? I looked up an image catalog, and it seems that if an Acura's going to be green, it is likely to be an NS-X, which are fairly exotic as Acuras go. I owned a black Integra for a while. If any had been green in those days, I would've definitely noticed! And, I definitely would've yielded the right-of-way to them, just so I could gawk and stare!
Der_Einzige 8mo ago
Doesn’t happen much in Portland OR, at least before the invasion of homelessness here. We had the most “nice” drivers in America.
justkys 8mo ago
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mitthrowaway2 8mo ago
I leave a lot of distance, but people rarely change lanes to get in front of me, because the person I'm following isn't going any faster; the separation is in d not v. Most people who do change in front of me are there only briefly on their way to an exit, which means I'm increasing the fluidity of the traffic flow, so I'm happy about that. If I didn't leave space, they'd likely hard-brake in front of someone, causing a slowdown.
tarsinge 8mo ago
> another car sees a gap and changes lanes in front of you Usually if you maintain the slightly slower speed you had to maintain a safe following distance it doesn't matter, as the distance will either increase or they'll leave for another lane. You have to get used to drivers doing messy things in front of you, but at a safe distance. When doing this you are in fact helping the traffic becoming more fluid.
bjackman 8mo ago
I find that respect for safe following distance varies quite a lot amongst the places I've driven. E.g. - Switzerland and (somewhat surprisingly) UK: pretty good, people doing idiotic shit is rare enough that I'll usually comment on it if there's another person is in the car. If someone is riding my ass I'll make the effort to try and shake them off. - Italy and Spain: horrifying, impossible to relax at all on the highway, having someone 2 car lengths off your rear bumper is the default condition. - France and USA: somewhere in the middle where there are a lot of idiots but they are still the minority. Subjectively, the USA feels much more sketchy because the rules are so much looser around overtaking.
- ninalanyon 8mo ago
  I think Belgium is the worst for tailgating but the French are pretty bad too.
alistairSH 8mo ago
Now try it with a heavy trailer, where you need even more room to brake and maneuver safely. People are just idiots.
MattRix 8mo ago
It’s not challenging at all. You leave the buffer. If someone sees the gap and merges into it, that’s fine! You always maintain the buffer. It’s not hard to do. It’s only frustrating if you let it be. It really barely slows you down at all.
hansvm 8mo ago
This was part of the training materials of one bus driver I knew. When people continually take that gap and you continually have to back off, it only adds a negligible amount of time to the commute.
angiolillo 8mo ago
> vehicle changes lanes in front of you; you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. For the sake of argument, assume you follow the "three second rule" and that the other driver is slightly aggressive and enters closer to the front of your safety buffer. You are now down to a two second safety buffer so rebuilding it back to three seconds costs you an extra second of travel time. In practice this happens to me about a dozen times a day. It sometimes feels frustrating, as if each of these drivers is stealing another second I could have been playing with my kids! But ultimately it's worth spending the extra seconds to slightly increase the odds that I arrive home each day to play with them at all.

amanaplanacanal 8mo ago

Does it really matter though? Is the end result just a couple of minutes later in a 30 minute commute? Or does it actually make a large difference in travel time?

mountain_peak 8mo ago
It used to be more of an issue when I was younger. Now that I'm older and more 'seasoned' (plus reflexes do slow down), I'm far more patient and have no issue maintaining a healthy following distance. I think the statistics reflect this in age vs. accident rate as well. Unfortunately, sometimes over a 45 minute freeway commute, dropping back repeatedly means arriving 15 minutes or more later. Again, no big deal now, but it was somehow unacceptable when I was younger.
- Noumenon72 8mo ago
  For your commute to take 4/3 the time, you would have to be averaging 3/4 the speed -- going 45 in a 60. That doesn't make sense because even going 55 would mean traffic pulled away from you rather than you having to drop back from it. Going 55/60ths the speed means you arrive in 60/55ths the time, or an extra 4 minutes on a 45 minute commute.
yial 8mo ago
It doesn’t - but people don’t necessarily make rational choices regarding speed and driving. There’s a tendency to de personalize other drivers. A slight increase in average speed really only makes a significant difference over long drives. (5 mph increase over a 10 hour drive can cut off 50 minutes). Otherwise we are talking about small differences in efficiency. (I would be very open to another opinion here.). My opinions are formed by nearly ~2 million miles driven at this point, two different driving courses, and the motorcycle safety course. One thing I truly think that’s overlooked is how reduced road noise in the vehicle cabin can both reduce driver fatigue, but also frustration in traffic.
- badc0ffee 8mo ago
  > (5 mph increase over a 10 hour drive can cut off 50 minutes) You can't really say that without knowing the starting speed, or alternatively the distance. All you can say is that a 5 mph increase over a 10 hour drive with get you 50 miles farther.
  - yial 8mo ago
    I would argue I can still say it /can/ cut off 50 minutes. If you do a comparison of a 600 mile trip at 60 vs 55 you’re pretty close. But yes, to be pedantic and more exact, you are spot on that it will get you 50 miles closer. But in real world examples, If you’re traveling 700 miles. 65 vs 70, 70 will reduce your time by 43 minutes. So in certain scenarios, 5 mph difference must be able to save you 50 minutes ! ;) (I do understand your point, and you’re correct. I’m just poking fun at it- my point with the mph difference is because 50 miles doesn’t have the same translation for most people at 50 minutes, but is a more accurate data approach. )
    - badc0ffee 8mo ago
      > So in certain scenarios, 5 mph difference must be able to save you 50 minutes ! ;) That is true. If you're going 55 mph for 10 hours, you'll go 550 miles. Increase your speed to 60 mph, and you'll get there at 9 hours 10 minutes.
- 8mo ago
avidiax 8mo ago
> Is the end result just a couple of minutes later in a 30 minute commute? More like a few seconds. Every car that merges in front of you only costs you their following distance. If the average following distance is 1 second, then you are simply 1 second slower than you'd have otherwise been. So unless this is happening continuously every 30 seconds on your 30 minute commute, you will lose less than a minute. The "but if I kept reasonable following distance, people will keep merging in front of me and I'll lose time" excuse is pretty thin given this analysis. And an insurance claim can easily eat 40 hours of time between the insurance companies, other lawyers, buying a new car, medical appointments and recovery. That's 19,200 minutes you won't get back, or about 52 years of driving 1 minute slower each day. Slow is smooth and smooth is fast.
cucumber3732842 8mo ago
I have been doing the same commute at the same time for the better part of a decade. At this point I can look at my watch and tell if I'm ahead of schedule or behind schedule and infer what the compounding effect will be later in my commute. I can easily shave 10% off my commute by lane changing to avoid the lanes where turn lane traffic tends to back up into the travel lanes, ramp traffic and "problem people". I test the null hypothesis several times a month by carrying bulky topheavy cargo that precludes a bunch of lane changing without more effort than I want to put in. I don't think there's much to be gained by simply lane changing to chase fleeting gaps in traffic. The wins and losses will probably mostly cancel out.

yial 8mo ago

This is accurate in many ways. I use the auto cruise feature on my car frequently and I notice several things happen unless I set the distance as close as possible (which I don’t like to do. ). 1. In any amount of traffic above “a few cars” people will cut in front of me, sometimes two, negating the safe following distance. Regardless of speed. 2. If I have a safe following distance while waiting for someone to get over. (I e they’re going 60, I want to go 70), if I have my distance set at a safe following distance, people are much more likely to weave / pass on the right. (My theory would be that the distance I’m behind the person in front of them signals that I’m not going to accelerate / pass when the person gets over ). Disclaimer: I don’t usually have to drive in any significant traffic, and when I do (Philly, New York City), I’m probably less likely to use the automatic features because the appropriate follow distance seems to increase the rage of drivers around me.

VladVladikoff 8mo ago
Just drive in the slow lane and you won’t have this problem. The people cutting in front of you rarely want to be in the slow lane.
- yial 8mo ago
  I do drive in the slow lane frequently - and this still occurs. (My go to is to set my cruise 6-9 mph over the speed limit, if passing to smoothly pass and get back over, and spend as much time as possible in the slow lane. ) However - I will say most of the roads I’m on are 2 lanes of traffic. I will have to experiment and see if this doesn’t occur when there are 3 or 4 lanes.
  - girvo 8mo ago
    The idea of cruising 15km/h over the limit is absolutely crazy to me. That will get you 3 points and a minimum $500 fine here. We have "average speed zones" too!
    - fredophile 8mo ago

ChuckMcM 8mo ago

Okay I'm thinking of a very Shenzen kind of gizmo for your car that projects a bright red laser "keep out" box on the road in front of your car which is adjusted in size for your current speed.

NitpickLawyer 8mo ago
We have something like that in eu with road markings. Both for clear weather and fog/rain. They mark some of the lines differently, and tell you how many lines you should have between you and the car in front. I think they were first trialed and then printed in several places.
- ChuckMcM 8mo ago
  Cool. But I'm thinking this box floats in front of your car on the road in real time. See you're driving and ahead of you on the road is this box. At night it might interfere with your night vision, might have to workshop that a bit.
- ErroneousBosh 8mo ago
  There's a couple of bits of motorway in England with that, I'm pretty sure the M6 and the M1. There are white chevrons painted on the road and you keep two of them between you and the car in front. Also "Keep Two Chevrons Apart" is going to be the name of my specialist Citroën breaker's yard.
  - ninalanyon 8mo ago
    And on the M5 between Gloucester and Bristol.
rootusrootus 8mo ago
I think a lot of people would just consider that a challenge. On the occasion when I am towing our travel trailer, it is really incredible how unsafe that makes other drivers act around me. They will jam themselves in front of me at all costs, with no consideration for physics.

duped 8mo ago

Why does this require "hard" braking? If another car cuts in front of you just decelerate gently. You don't brake and wait until the gap is big enough (also if this is stop-and-go traffic, you should be trying to avoid braking at all)

mountain_peak 8mo ago
My original observation wasn't worded as well as it could have been. I meant in situations where hard braking could be required on a moment's notice for no particular reason (e.g. Chicago freeways where everyone is doing 70 mph bumper-to-bumper and decreases to 10 mph all of a sudden). Indeed, when someone changes lanes in front of me, I gently let off the accelerator, but as someone else noticed, that can enrage drivers behind me (I don't take it personally), and I'm definitely traveling fast enough to remain in the middle lanes.

sagarm 8mo ago

If you think highway driving requires hard braking, you're a bad driver.

appreciatorBus 8mo ago
Yes. If people are constantly moving into your appropriate head way this is doubtless annoying but the correct response is allow yourself to decelerate slowly to re-open that space again, repeat as many times as necessary, even if it means a bunch of agros end up in front of you. Better for them to be in front where you can see them, than behind or to the side, were you can't.
- mlyle 8mo ago
  Yah. There's something that feels unjust about it -- the perception that the people cutting are getting something over on you -- that causes us to want to behave badly. But even if 2 dozen people go around you and creep into that following space, you've been cost like 45 seconds at worst. Better not to play the game.
  - cmurf 8mo ago
    They are likely getting more frequent brake pad replacements. Not a significant cost. But they sure as shit aren't getting what they think they're getting. Meaningfully farther ahead. I now see it all as a risk assessment rather than as ritualistic combat.
    - its_magic 8mo ago
      If you added a missile launcher to your vehicle, it could become ritualistic combat again.
  - ryandrake 8mo ago
    Society would have a lot fewer car accidents if we, collectively, could get over that "Oh no someone dared to get in front of me!" feeling.

kube-system 8mo ago

If you think people are going to cut in front of you, provide a safety cushion large enough to account for that. Aggressive drivers almost universally will consume the forward part of the space cushion you leave. At most you will simply need to lift the accelerator to maintain space. The only time someone cutting in front of you should require hard braking is if they also brake hard. It does require patience to do this, because all aggressive drivers will use the space you provide. But ultimately the travel time difference in flowing traffic is negligible.

MostlyStable 8mo ago
I'm not sure it's that negligible. Mythbusters found that weaving in and out of traffic could save between 5 and twenty-five percent. Now A) Mythbusters did an experiment with an N of like 4 or something, along a single commute in the Bay Area, so it's basically anecdote and I'd love a better source if one existed, but it is at the very least proof-by-existence that larger impacts on travel time _can_ happen. And their non-weaving person was, if I recall from the video, not constantly decelerating to keep a buffer. And from personal experience in some places, keeping such a buffer, in some traffic conditions would just literally be impossible. There are sometimes enough aggressive drivers such that they can just consume it faster than one would be able to create it. It is simply not always the case that you have sole power to create and keep the recommended buffer size (although very often it is and you can). I keep a decent buffer whenever I am able, but at some point, you have to bow to road conditions.
- streetfighter64 8mo ago
  25% of time saved corresponds to increasing your average speed by 1/(1-0.25)=33%, for example from 45 to 60.
cucumber3732842 8mo ago
Letting a large fraction of the freeway cut in front of you will turn normal drivers behind you aggressive, or at least aggressive enough to go around you. There's a balance to be struck.

bluGill 8mo ago

False. I've done it many times - when you open up space two cars jump in, but the rest don't and so the space remains. But you notice those two cars and think it means more than it does.

OptionOfT 8mo ago

> North America Having driven all over NA, and Europe, I find it more prevalent in NA. Less distance, more people in large pickups throwing their weight around to make someone move out of the way. And a design of giant freeway interchanges that require shifting lanes. E.g. on the 405 in CA. 7 lines going South from the Valley towards Santa Monica. That's 7 lanes you need to cross if you're in the HOV lane.

ChoGGi 8mo ago
> That's 7 lanes you need to cross if you're in the HOV lane. The 401 is my favourite with eighteen lanes, four for the inner express lanes, and five for the collector lanes. https://en.wikipedia.org/wiki/Ontario_Highway_401#/media/File%3AHighway_401_cropped.png https://en.wikipedia.org/wiki/Ontario_Highway_401#/media/Fil...
vincston 8mo ago
Honestly imo the driving license requirements and the respective fines for violations is too low. Rigid rules generally improve the traffic flow. But as soon as someone just doesnt care, the system breaks down.

gwbas1c 8mo ago

I'm one of the faster drivers and I maintain a safe distance. (I usually have the most distance in rush hour.) It's very easy with adaptive cruise control or the other self-driving technologies that are on the market. The only people who cut too close to me are driving recklessly. That being said: If you're in the mode where people are constantly changing lanes in front of you, think a bit about how you're driving: On the freeway you're supposed to stay to the right except to pass, and you're expected to keep up with the flow of traffic. Are you going slow in the left lane? Are you driving too slow? Are you camping in the right lane by a busy interchange?

thewebguyd 8mo ago
> and you're expected to keep up with the flow of traffic. This is very state dependent, if we are talking about legality. In WA state, for example, there is no "flow of traffic" law or similar. The limit is the limit, and any excess of the speed limit is illegal regardless of what all other drivers are doing. So even if the right/slow lane is going 100MPH through the 70MPH zone, you are legally expected to still go 70. Thankfully we do have laws against left lane camping, but I rarely see it enforced.
- Dylan16807 8mo ago
  > This is very state dependent, if we are talking about legality. Are you sure? And by that I mean, are you sure there are states that don't work the way WA works?
- skue 8mo ago
  You’re confused. If you know of ANY US state that has a flow of traffic law that allows cars to exceed the speed limit so long as they are keeping up with other traffic, I’d love to see a link to their traffic codes. Speeding doesn’t suddenly become legal because two or more drivers do it together. This has nothing to do with the expectation that slower traffic stay in the rightmost lanes, which is what GP is addressing.
  - gwbas1c 8mo ago

sershe 8mo ago

The most frustrated people are those behind you, and if I was id soon be another person merging in front of you. If people are constantly merging in front of you, either everyone is going too fast or you are going too slow :)

Gravityloss 8mo ago

I live in a place that has harsh winter conditions with ice, gravel and the occasional loose tire stud flying into people's windshields, warranting frequent expensive replacements. Somebody on the radio said that "just set the adaptive cruise control to max distance and your windshield will last way longer". It does feel overprotective at times, especially in slow and dense traffic, but I think there's a nice point in general.

stevage 8mo ago
Wow, I didn't know that was a thing. Been driving nearly 30 years, and never had a windshield chip.
- its_magic 8mo ago
  Do you have a wood surface nearby? I would recommend giving it a good knock.
  - stevage 8mo ago
    Apparently I just live in a place where it's not a common problem. Also I do tend to leave a big gap behind cars in front.
    - ChoGGi 8mo ago
      They salt your roads, or put grit?
      - stevage 8mo ago
        They don't do either of those things, and yet somehow I haven't witnessed any cars sliding off the road in winter either.
        its_magic 8mo ago
        From everything you've said so far, it sounds like people in your area have a lot of sense.

bloomingeek 8mo ago

Tailgating is against the law. Tailgating causes hard braking. I recently pulled my travel trailer from OK to Charleston, SC and back. I never drive over 65 MPH for safety and MPG reasons. I always stay in the right hand, slow lane except if I have to take a left lane exit. Since I was always driving slower then everyone else, not once did I have to hard brake. Tailgating is a choice and a dangerous one. I was never honked at, even by the crazy semi truck drivers.

rconti 8mo ago
Even that can be tricky, with the indecisive behavior people use when merging.
- tadfisher 8mo ago
  That one's easy: leave space in front of you for those merging onto the highway. So much of road etiquette boils down to leaving adequate space so others can maneuver around you. Trying to optimize your travel by destroying any gaps as soon as they appear actually has the opposite effect.
  - HPsquared 8mo ago
    James May calls this "Christian motoring". Golden Rule etc
  - dekhn 8mo ago
    While leaving space is nice, the person on the highway already typically has right-of-way.
  - rconti 8mo ago
    It's really not. I drive at an upper-percentile pace, so I am rarely dawdling along in the right lane. However, on the rare occasion I've found myself going slowly in the right lane, it's stunning how incompetent most people are at merging. It's like they don't even consider looking for an opening in traffic, matching the freeway speed, etc. They just lumber in front of you at 43mph, and maybe, if you're lucky, look in their mirrors after they've already caused you to slow for them.

rconti 8mo ago

I find it quite easy to hold/manage a tight space that people won't cut into, and don't have to brake hard, because I look ahead. To be sure, it's more mentally taxing to hold a tight gap, so it's not something you want to do all the time, but it's fine.

trgn 8mo ago

> another car sees a gap and changes lanes in front of you. it's largely a problem in the left lanes, thats where drivers will bunch up most. the subjective feeling is mostly a reptile brain issue though, the feeling you're getting done over. driving is 90% id, sadly.

Sohcahtoa82 8mo ago

> vehicle changes lanes in front of you; I will never understand why this is so rage-inducing for people. Changing lanes is a necessary part of navigating, even during busy traffic. People on an on-ramp will need to get in front of somebody. People needing to move back to the right because their exist is coming up will need to get in front of somebody. Your lane is not a birth right. Let people merge. > you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. This happens because literally everyone is tailgating each other so hard that the gap in front of you is the only gap that exists for people to change lanes to either get on or off the highway.

loeg 8mo ago
It's frustrating when it eats into your safe following distance. The driver merging in ahead of you is being dangerous and not leaving a safe following distance for themselves (or you).
- Sohcahtoa82 8mo ago
  When traffic is heavy, everyone is likely following at [what they perceive to be] a minimum following distance. It's simply not possible to merge during heavy traffic without eating into someone's safe following distance.
- MPSimmons 8mo ago
  The buffer exists to be used. Allowing people to merge into it makes the lane that they came from safer. Build a new buffer.
- idiotsecant 8mo ago
  It takes almost no effort to restore your safe distance again.
- ndsipa_pomu 8mo ago
  What's the problem with reducing speed and reclaiming a safe following distance?

Dylan16807 8mo ago

I admit that I probably don't leave as much space as recommended, but I leave a good amount of space to never need to hard brake, and people don't keep moving in front of me either.

bsder 8mo ago

Maintaining a following distance is going to be one of the things that improves dramatically once self driving cars are widespread. Self-driving cars simply don't care that someone cut them off, they'll just happily open up extra space again and again.

ninalanyon 8mo ago
You don't need self driving, just traffic aware cruise control. Pretty much every modern car can have this as most now come with automatic emergency breaking and the same sensors can be used.

Izikiel43 8mo ago

> Maintaining a safe following distance is incredibly challenging on busy freeways I just put adaptive cruise control on max distance and call it a day, gives me 4/5s to react, and also it starts beeping hard if intervention is required. It has saved my bacon a couple of times.

singingbard 8mo ago

I actually disagree. People only take your lane if you are in the fastest lane. If you are in any slower lane, people tend to jump in and then leave and I have no problem with people who do that. You can also keep a gap in the fastest lane but you need to keep track of other cars on the road. You’ll observe that most cars rarely leave their lane. People who tend to leave their lane keep smaller gaps in front of them. Use that knowledge. There are many more factors than just that but if you start observing everyone drive, your little simulation in your head will start putting other drivers into buckets.

bcraven 8mo ago
These comments make me grateful that we have the concept of 'lane discipline' in the UK. It's rare to see the 'fastest' lane be anything other than the outside one. Otherwise we keep left and out of the way. https://www.highwaycodeuk.co.uk/lane-discipline.html https://www.highwaycodeuk.co.uk/lane-discipline.html

apparent 8mo ago

Totally. People will just cut you off repeatedly, which puts you (and the cars behind you) in a less-safe situation than if you followed more closely.

ninalanyon 8mo ago
> puts you (and the cars behind you) in a less-safe situation than if you followed more closely. Really? All you have to do is lift your right foot very gently until you have the expected spacing again, no need to sudden changes of speed and if you have traffic aware cruise control it will be done for you. My old Tesla S does it pretty well. I keep it set to three second spacing and when someone cuts in front my car just gently slows down until the spacing is correct again; it doesn't brake unless the car that cuts in is very close.
- apparent 8mo ago
  Yeah totally works like that, until you get cut off 10 seconds later by another car. If this doesn't happen to you, then you're probably driving like I do, and not leaving 3 seconds of follow distance like they teach in driver's ed.
  - ninalanyon 8mo ago
    I do keep three seconds separation most of the time. If possible I engage traffic aware cruise control set to maximum separation for just that purpose. People do cut in but not often; what would be the point of cutting in between two vehicles that are both going slower than your desired speed? Also perhaps I should have made it clear that I am in Europe where one is expected and required to drive in the outermost (rightmost except in UK and Ireland) lane unless overtaking so the only time anyone would 'cut in' between my car and the one in front is when they are entering a motorway.

whitexn--g28h 8mo ago

This almost always happens when you are in the passing lane, and you are not passing. It’s much more rare in the right lane. Mythbusters, and also other traffic studies, show that returning to the right lane on the freeway whenever possible adds almost no time to a trip.

patcon 8mo ago

gah YES. I had a slow realization that I could just let people jump in. My goal is to maintain a constant speed and never have to hit the brakes, and I can usually still do that regardless of whether people jump line. But yes, the principle of it is incredibly aggravating ("that space is for safety, not YOU, green Acura!!!") but I actually kinda like the practice of trying to be zen about it. I mostly get through a long trip at the same rate :)

RupertSalt 8mo ago
Woah, like, "green Acura"? Where are you driving that you ever see one of those? In the USA? I looked up an image catalog, and it seems that if an Acura's going to be green, it is likely to be an NS-X, which are fairly exotic as Acuras go. I owned a black Integra for a while. If any had been green in those days, I would've definitely noticed! And, I definitely would've yielded the right-of-way to them, just so I could gawk and stare!

Der_Einzige 8mo ago

Doesn’t happen much in Portland OR, at least before the invasion of homelessness here. We had the most “nice” drivers in America.

justkys 8mo ago

[dead]

mitthrowaway2 8mo ago

I leave a lot of distance, but people rarely change lanes to get in front of me, because the person I'm following isn't going any faster; the separation is in d not v. Most people who do change in front of me are there only briefly on their way to an exit, which means I'm increasing the fluidity of the traffic flow, so I'm happy about that. If I didn't leave space, they'd likely hard-brake in front of someone, causing a slowdown.

tarsinge 8mo ago

> another car sees a gap and changes lanes in front of you Usually if you maintain the slightly slower speed you had to maintain a safe following distance it doesn't matter, as the distance will either increase or they'll leave for another lane. You have to get used to drivers doing messy things in front of you, but at a safe distance. When doing this you are in fact helping the traffic becoming more fluid.

bjackman 8mo ago

I find that respect for safe following distance varies quite a lot amongst the places I've driven. E.g. - Switzerland and (somewhat surprisingly) UK: pretty good, people doing idiotic shit is rare enough that I'll usually comment on it if there's another person is in the car. If someone is riding my ass I'll make the effort to try and shake them off. - Italy and Spain: horrifying, impossible to relax at all on the highway, having someone 2 car lengths off your rear bumper is the default condition. - France and USA: somewhere in the middle where there are a lot of idiots but they are still the minority. Subjectively, the USA feels much more sketchy because the rules are so much looser around overtaking.

ninalanyon 8mo ago
I think Belgium is the worst for tailgating but the French are pretty bad too.

alistairSH 8mo ago

Now try it with a heavy trailer, where you need even more room to brake and maneuver safely. People are just idiots.

MattRix 8mo ago

It’s not challenging at all. You leave the buffer. If someone sees the gap and merges into it, that’s fine! You always maintain the buffer. It’s not hard to do. It’s only frustrating if you let it be. It really barely slows you down at all.

hansvm 8mo ago

This was part of the training materials of one bus driver I knew. When people continually take that gap and you continually have to back off, it only adds a negligible amount of time to the commute.

angiolillo 8mo ago

> vehicle changes lanes in front of you; you slow down to maintain a safe following distance, another car sees a gap and changes lanes in front of you. Repeat for your entire commute. For the sake of argument, assume you follow the "three second rule" and that the other driver is slightly aggressive and enters closer to the front of your safety buffer. You are now down to a two second safety buffer so rebuilding it back to three seconds costs you an extra second of travel time. In practice this happens to me about a dozen times a day. It sometimes feels frustrating, as if each of these drivers is stealing another second I could have been playing with my kids! But ultimately it's worth spending the extra seconds to slightly increase the odds that I arrive home each day to play with them at all.