# Why do semis block all lanes of traffic on the interstate **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [May 25, 2013, 1:03am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280 "2013-05-25T01:03:26Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [May 25, 2013, 1:03am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/1 "2013-05-25T01:03:26Z")
If there are 2 lanes on the interstate it is not uncommon for 2 semis to block them both, driving side by side so nobody can pass them. Either they will be staggered or they will be side to side and they will drive like that for miles. There are signs on the road saying ‘trucks with trailers keep right’ so this must be an issue. What is in it for them? They make the rest of us drive 10mph slower and they prevent anyone from passing. Why is that something they would benefit from? ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [May 25, 2013, 1:26am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/2 "2013-05-25T01:26:38Z")
> [@Wesley\_Clark](#): > > If there are 2 lanes on the interstate it is not uncommon for 2 semis to block them both, driving side by side so nobody can pass them. It’s uncommon around here (New England). I’ve rarely if ever seen it. Where are you seeing this? ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [May 25, 2013, 1:27am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/3 "2013-05-25T01:27:57Z")
One is driving a tiny bit faster than the other and is slooooowly passing. ---
**Author:** ![ZipperJJ](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zipperjj/32/211_2.png) [@ZipperJJ](https://boards.straightdope.com/u/ZipperJJ)\ **Post date:** [May 25, 2013, 1:43am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/4 "2013-05-25T01:43:46Z")
Yeah I don’t think they’re doing it on purpose. That’s just how the dice landed at the moment. One might be in the left lane to avoid traffic merging in from the right lane, and they just happen to both be going the same speed. Or, truckers are damn bored. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [May 25, 2013, 1:47am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/5 "2013-05-25T01:47:53Z")
Some people are assholes. Some assholes drive trucks. ---
**Author:** ![silenus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/silenus/32/166_2.png) [@silenus](https://boards.straightdope.com/u/silenus)\ **Post date:** [May 25, 2013, 1:48am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/6 "2013-05-25T01:48:57Z")
Most drivers are really good at avoiding things like that. But they aren’t driving sports cars. When one semi passes another, it takes time. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [May 25, 2013, 1:50am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/7 "2013-05-25T01:50:28Z")
I found this thread. > **[Trucks blocking traffic](https://boards.straightdope.com/sdmb/showthread.php?t=107646)** > > Just got back from a road trip. On occasion, I would see 2 trucks driving side by side at the same speed. The effect would be open road ahead of them and a huge backup behind them. Does anyone know what the rationale for this is? Or the effect on... According to that, a big reason is they are trying to encourage merging a few miles before road construction. But I have seen this behavior when there was no road construction ahead. So that explanation doesn’t work. It isn’t an accident, sometimes they will drive for miles and miles like that where they will block all lanes of traffic. It doesn’t take that long to pass even if you are only going 1mph faster, since even at that speed you are traveling 88 feet/minute which means it would take 2-3 minutes at best to pass if one truck were going 1mph faster than the other. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [May 25, 2013, 2:05am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/8 "2013-05-25T02:05:37Z")
> [@Wesley\_Clark](#): > > It isn’t an accident, sometimes they will drive for miles and miles like that where they will block all lanes of traffic. Again, where are you seeing this? ---
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [May 25, 2013, 2:58am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/9 "2013-05-25T02:58:46Z")
> [@Telemark](#): > > Again, where are you seeing this? I’ve seen it. A number of times. I’ve spent a lot of time on cross-country motorcycle trips. I’ve seen truckers do this. Sometimes it seemed that the truckers were acting as some kind of self-appointed merge police or something. Sometimes I couldn’t figure out why they were doing it. My memory is that I saw it in the midwest, and not anywhere else. I specifically remember one time in Kansas, where I just got sick of it and lane-split through the cars behind the trucks, went around the trucks on the shoulder, and then sped down the (now empty) highway for miles without seeing anything that could explain this behavior. I never could figure it out. Oh, and **ZipperJJ** – they were _absolutely_ doing it on purpose. There was no possibility whatsoever that it wasn’t intentional. ---
**Author:** ![Emtar\_KronJonDerSohn](https://avatars.discourse-cdn.com/v4/letter/e/58956e/32.png) [@Emtar\_KronJonDerSohn](https://boards.straightdope.com/u/Emtar_KronJonDerSohn)\ **Post date:** [May 25, 2013, 3:01am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/10 "2013-05-25T03:01:07Z")
Generally it’s because both trucks are governed at or around 68mph and one of them wants to pass the other. Neither of them wants to slow down and neither of them _can_ speed up. I’ve seen this in Arizona quite a bit. The speed limit on most interstates is 75 and a lot of cars drive 80-100 so even a relatively fast pass by two trucks going 68 or so traps a lot of cars. ---
**Author:** ![Becky2844](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@Becky2844](https://boards.straightdope.com/u/Becky2844)\ **Post date:** [May 25, 2013, 3:06am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/11 "2013-05-25T03:06:35Z")
We’re from East TN and Knoxville was our metropolis. Apparently Knoxville is to trucks as Atlanta is to planes; if you want to go to, you have to go through. Semis rule the road there. One time I counted over 100 trucks between our shopping expedition back home. They box you in—one in front, one in back, one at your side. We learned to shit on Saturdays when we were more relaxed. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [May 25, 2013, 3:10am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/12 "2013-05-25T03:10:23Z")
> [@Becky2844](#): > > We learned to shit on Saturdays when we were more relaxed. Huh? Is that a Southern thing? ---
**Author:** ![Suburban\_Plankton](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/suburban_plankton/32/219_2.png) [@Suburban\_Plankton](https://boards.straightdope.com/u/Suburban_Plankton)\ **Post date:** [May 25, 2013, 3:11am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/13 "2013-05-25T03:11:31Z")
I’ve never seen truckers “blocking all lanes of traffic”, and I’ve taken plenty of trips down I-5 in California where trucks have outnumbered cars. What I have seem plenty of times is one truck passing another, and taking a mile or more to do it, but that’s just the way it works. Semis are not sportscars. It used to bug me, because I had to slow down and wait for them to finish their dance…but as I’ve gotten older I think I’ve gotten a lot more patient. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [May 25, 2013, 4:46am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/14 "2013-05-25T04:46:03Z")
> [@Becky2844](#): > > We learned to shit on Saturdays when we were more relaxed. Most medical authorities agree that defecating only once a week probably is not ideal for your average person. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [May 25, 2013, 4:48am UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/15 "2013-05-25T04:48:03Z")
> [@Qadgop\_the\_Mercotan](#): > > Most medical authorities agree that defecating only once a week probably is not ideal for your average person. Particularly when the movement is in a moving car. ---
**Author:** ![Becky2844](https://avatars.discourse-cdn.com/v4/letter/b/91b2a8/32.png) [@Becky2844](https://boards.straightdope.com/u/Becky2844)\ **Post date:** [May 25, 2013, 12:59pm UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/16 "2013-05-25T12:59:40Z")
😛 ---
**Author:** ![HipGnosis](https://avatars.discourse-cdn.com/v4/letter/h/76d3ee/32.png) [@HipGnosis](https://boards.straightdope.com/u/HipGnosis)\ **Post date:** [May 25, 2013, 1:04pm UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/17 "2013-05-25T13:04:36Z")
Many trucks have their top speed limited by governors. No 2 trucks will have the exact same top speed due to all the variances involved. A truck limited to 60.3 mph is gonna take a while to pass a truck limited to 60.1. It’s further compounded by the loads they’re hauling. Many trucks can’t maintain their max speed when going up a hill when fully loaded. So trucks downhill and uphill speeds can be quite different. If it’s 2 trucks paralleling each other on purpose - the drivers are dicking around for totally personal reasons. ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [May 25, 2013, 1:06pm UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/18 "2013-05-25T13:06:22Z")
Some vehicles did this years ago to protest the national 55 mph speed limits. [Cite…](http://articles.chicagotribune.com/1996-02-18/news/9602180289_1_speed-limit-national-motorists-association-michigan-chapter) ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [May 25, 2013, 1:16pm UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/19 "2013-05-25T13:16:07Z")
> [@Emtar\_KronJonDerSohn](#): > > Generally it’s because both trucks are governed at or around 68mph and one of them wants to pass the other. Neither of them wants to slow down and neither of them _can_ speed up. > > I’ve seen this in Arizona quite a bit. The speed limit on most interstates is 75 and a lot of cars drive 80-100 so even a relatively fast pass by two trucks going 68 or so traps a lot of cars. I think that’s it- one or the other has a governor, so they can’t just stomp on it and pass like a car would. Instead, they do this slow-motion ballet passing- the passer can’t go much faster, and the passee doesn’t want to slow down too much because it’s hard to get back up to speed fast, so the rest of us have to wait while they do their thing. My big question is why SO much crap is being shipped by truck- it seems like the number of trucks on the interstate has gone up significantly in the past decade, and I can’t imagine that it’s all short-hop intermodal stuff, where the loads are carried by rail near to the delivery point. Shouldn’t most of this stuff be shipped by rail if it’s going more than 300 miles or so? ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [May 25, 2013, 1:21pm UTC](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280/20 "2013-05-25T13:21:19Z")
Aside from cluelessness and the distraction of yapping on their cellphones, another reason for this occasional trucker behavior is to “punish” the driver of a car who wants to pass, but has offended them or their buddies. Others are mere collateral damage. > [@Qadgop\_the\_Mercotan](#): > > Most medical authorities agree that defecating only once a week probably is not ideal for your average person. Or your average plumbing system. [Next page](https://boards.straightdope.com/t/why-do-semis-block-all-lanes-of-traffic-on-the-interstate/659280.md?page=2)