# Semi-trucks driving VERY SLOWLY with hazard lights on **URL:** \ **Category:** Factual Questions\ **Created:** [July 29, 2015, 11:14pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534 "2015-07-29T23:14:14Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [July 29, 2015, 11:14pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/1 "2015-07-29T23:14:14Z")
On the freeway near where I live, every time I come home there’s almost always some big semi on the far right-hand lane with its hazard lights on, driving at a snail’s pace of about 30-40 MPH in a 65 zone. It’s so bizarre because I don’t see this happening in other places, just this particular stretch of freeway within a few miles of my home. If it were an isolated incident I’d think that the driver was having some kind of mechanical problem, but I see it _constantly_, only on this particular part of the freeway. It’s absolutely infuriating because this is a 8-10 lane freeway with a fair amount of traffic, and the second-to-right lane is also usually filled up with semi trucks going faster than the ones with blinking hazards, but still rather slow (since they’re semis), and when I am trying to get home I often get sandwiched into one of these lanes as I’m trying to make my way to my exit and sometimes get completely stuck behind one of the 30 MPH behemoths. So my question is, WTF? Why do so many trucks, only on this particular stretch of freeway, drive so incredibly slowly? It’s not all the trucks, but there’s always someone. ---
**Author:** ![yoyodyne](https://avatars.discourse-cdn.com/v4/letter/y/a9a28c/32.png) [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)\ **Post date:** [July 29, 2015, 11:22pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/2 "2015-07-29T23:22:03Z")
Is the road going uphill? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [July 29, 2015, 11:27pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/3 "2015-07-29T23:27:05Z")
Typically, IME, when that’s happening it means one of the tire treads is coming off and he’s slowing down so it doesn’t go flying. If it’s always happening in one spot there might be something causing it. There could also be something about that stretch of road that truckers just don’t like to go over fast. A big bump or nasty pothole maybe. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [July 29, 2015, 11:29pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/4 "2015-07-29T23:29:16Z")
I’m going to guess the “uphill” answer too. ---
**Author:** ![bb49](https://avatars.discourse-cdn.com/v4/letter/b/b38774/32.png) [@bb49](https://boards.straightdope.com/u/bb49)\ **Post date:** [July 29, 2015, 11:41pm UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/5 "2015-07-29T23:41:03Z")
> [@yoyodyne](#): > > Is the road going uphill? Is the road going downhill? I live in a fairly mountainous part of the world, and on the big hills, all the trucks use their four-ways going up and down the steeper hills. A number of the hills even have runaway lanes for trucks that might have lost their brakes. Maybe they find them at the bottom of the hill! ---
**Author:** ![Nefario](https://avatars.discourse-cdn.com/v4/letter/n/59ef9b/32.png) [@Nefario](https://boards.straightdope.com/u/Nefario)\ **Post date:** [July 30, 2015, 12:25am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/6 "2015-07-30T00:25:46Z")
Have they just appeared from an entrance ramp with a heavy load? Is there a factory area or heavy equipment yard along that stretch of load? One of my pet peeves is truckers playing traffic cop in construction areas and slowing or stopping all but the right lane with a SLOWLY rolling road block. ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [July 30, 2015, 12:29am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/7 "2015-07-30T00:29:17Z")
> [@Nefario](#): > > One of my pet peeves is truckers playing traffic cop in construction areas and slowing or stopping all but the right lane with a SLOWLY rolling road block. Reason #613 “Why to ride a motorcycle” ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 30, 2015, 12:33am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/8 "2015-07-30T00:33:27Z")
yeah, I’d say “uphill” too. just south of Detroit, I-75 has a long overpass over the River Rouge, and there’s a construction companies and a Marathon refinery straddling it. heavily-loaded trucks can get on 75 at the base of the overpass, and they simply don’t have enough power to get up to highway speed going uphill. So they do put on their 4-ways. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [July 30, 2015, 12:38am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/9 "2015-07-30T00:38:16Z")
Trucks go very slow uphill and downhill on I-40 just east of Asheville NC since that is the start of the mountains . The downhill lanes have 3 runaway truck ramps. I did see a truck in one of those ramps . ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [July 30, 2015, 12:44am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/10 "2015-07-30T00:44:17Z")
There’s a bit of an uphill section, yes, but why is it most trucks can maintain their normal speeds and it’s just a handful that crawl along at 30 MPH in the right lane? ---
**Author:** ![yoyodyne](https://avatars.discourse-cdn.com/v4/letter/y/a9a28c/32.png) [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)\ **Post date:** [July 30, 2015, 12:47am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/11 "2015-07-30T00:47:58Z")
Some trucks are fully loaded, some partially, some empty. Some trucks have more powerful engines than others. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [July 30, 2015, 12:48am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/12 "2015-07-30T00:48:44Z")
maybe the slow trucks have very heavy loads? It could be they are all heading to the same place with certain item(s) that are much heavier than normal. ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [July 30, 2015, 12:53am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/13 "2015-07-30T00:53:23Z")
Eh, I guess that makes sense. Still pisses me right off when I get stuck behind them and can’t easily pass due to traffic and to my exit coming up soon. ---
**Author:** ![yoyodyne](https://avatars.discourse-cdn.com/v4/letter/y/a9a28c/32.png) [@yoyodyne](https://boards.straightdope.com/u/yoyodyne)\ **Post date:** [July 30, 2015, 12:59am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/14 "2015-07-30T00:59:35Z")
The truckers don’t enjoy it much either. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [July 30, 2015, 1:18am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/15 "2015-07-30T01:18:13Z")
> [@Rigamarole](#): > > There’s a bit of an uphill section, yes, but why is it most trucks can maintain their normal speeds and it’s just a handful that crawl along at 30 MPH in the right lane? because those trucks have maybe 400 or so horsepower, and they’re hauling around 80,000 lbs. ---
**Author:** ![ssgenius](https://avatars.discourse-cdn.com/v4/letter/s/b5ac83/32.png) [@ssgenius](https://boards.straightdope.com/u/ssgenius)\ **Post date:** [July 30, 2015, 2:13am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/16 "2015-07-30T02:13:26Z")
Ancesdotal story but many years ago, I would commonly drive a smaller truck weighting about 40 000 lbs up a fairly steep hill. The truck was a 1984 model and it had a whopping 210 hp. This was across a river so going down on one side and I would max out its speed (about 75 mph). As soon as the uphill hit, the truck would just slow down like hitting the brakes. By the time I got to the top of the hill, I was down to 4th or 5th gear (out of 13) and down to about 20 mph and this was with the pedal to the metal and yes I put the flashers on. ---
**Author:** ![GusNSpot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gusnspot/32/436_2.png) [@GusNSpot](https://boards.straightdope.com/u/GusNSpot)\ **Post date:** [July 30, 2015, 4:25am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/17 "2015-07-30T04:25:42Z")
> [@Rigamarole](#): > > Eh, I guess that makes sense. Still pisses me right off when I get stuck behind them and can’t easily pass due to traffic and to my exit coming up soon. If it happens so much, you can tells us about road condition & grade. Nearness of on / off ramps, etc… What kind of trucks? 18 wheel only, bulk haulers ( like a big dump truck ) flat beds dry box reefer Also what companies? Pam CCI Road Way Yellow etc JB Hunt In state companies? ( look at the doors ) Day haul or sleepers? There can be as many different answers as the number of questions asked, maybe even more. 🆒 ---
**Author:** ![davida03801](https://avatars.discourse-cdn.com/v4/letter/d/b5e925/32.png) [@davida03801](https://boards.straightdope.com/u/davida03801)\ **Post date:** [July 30, 2015, 6:48am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/18 "2015-07-30T06:48:56Z")
Which road where ? ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [July 30, 2015, 6:57am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/19 "2015-07-30T06:57:21Z")
I don’t pay close enough attention to tell you companies or truck types other than they’re your typical large semi, but this is near the intersection of the 60 and 215 freeways. A few miles south is a big Amazon fulfillment warehouse, along with a lot of other warehouse property, so I’m sure many trucks head that way. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [July 30, 2015, 7:00am UTC](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534/20 "2015-07-30T07:00:22Z")
There’s no law that says the heavy trucks have to put on their blinkers below around 40 mph going uphill. It’s something taught in CDL class and passed along much before CDL requirements. Reduces chances that someone runs up your butt on the uphill (or downhill when geared down to control speed). Lets the fellow truckers with more power/lighter loads get out and pass. \*CDL = Commercial Driver’s License [Next page](https://boards.straightdope.com/t/semi-trucks-driving-very-slowly-with-hazard-lights-on/726534.md?page=2)