# Under what circumstances would police slow, but not stop, traffic? **URL:** \ **Category:** Factual Questions\ **Created:** [August 27, 2012, 12:13am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768 "2012-08-27T00:13:06Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![freckafree](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/freckafree/32/3050_2.png) [@freckafree](https://boards.straightdope.com/u/freckafree)\ **Post date:** [August 27, 2012, 12:13am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/1 "2012-08-27T00:13:06Z")
This morning, while traveling northbound on the interstate, I saw in the southbound lane two police cars driving abreast (not driving a breast – but I’ll give you a moment to get that image out of your mind…). They were driving slower than the speed limit and positioned so no one could get around them. Under what circumstances might the police want to slow traffic but not stop or reroute it? ---
**Author:** ![IvoryTowerDenizen](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ivorytowerdenizen/32/17937_2.png) [@IvoryTowerDenizen](https://boards.straightdope.com/u/IvoryTowerDenizen)\ **Post date:** [August 27, 2012, 12:14am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/2 "2012-08-27T00:14:41Z")
Perhaps there was an oversized load (like moving a house or huge construction equipment) ahead. ---
**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:** [August 27, 2012, 12:14am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/3 "2012-08-27T00:14:57Z")
Sometimes funeral processions go on the highway. Could be that they were clearing up to the entrance and then will keep pace once the entire procession has gotten on. ---
**Author:** ![jeffgorc](https://avatars.discourse-cdn.com/v4/letter/j/ec9cab/32.png) [@jeffgorc](https://boards.straightdope.com/u/jeffgorc)\ **Post date:** [August 27, 2012, 12:39am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/4 "2012-08-27T00:39:30Z")
It could be what is called a rolling roadblock. For some construction or maintenance operations like line painting, picking up debris, or pothole repairs, the police cruisers would slow down and allow the work crews to get ahead of them and do their work. They do this so the work can be done quicker without having to put out all the signs, cones, and flashing arrows when lanes are closed. By moving slowly, it is a little safer than just stopping the traffic and the drivers don’t get pissed off as much. ---
**Author:** ![Garfield226](https://avatars.discourse-cdn.com/v4/letter/g/9e8a1a/32.png) [@Garfield226](https://boards.straightdope.com/u/Garfield226)\ **Post date:** [August 27, 2012, 1:49am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/5 "2012-08-27T01:49:11Z")
It would also have the effect of [clearing up a traffic jam](http://trafficwaves.org/) not caused by an accident (or caused by a now-cleared accident). I have no idea if any departments actually do this for this reason, but I don’t see why it wouldn’t work. ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [August 27, 2012, 3:07am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/6 "2012-08-27T03:07:13Z")
On I-15 in SLC, I was following a Trooper that turned on his overhead lights and began slowly weaving side-to-side. He eventually had all four lanes down to about 20mph. Then, he turned them off and we all went on our way. I assume that this was training for just such an event. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [August 27, 2012, 3:14am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/7 "2012-08-27T03:14:55Z")
Was it at noon? There’s a rather large church in my area that has so many people trying to leave at noon that the cops have to do a rolling roadblock like that to let them out. ---
**Author:** ![gunnergoz](https://avatars.discourse-cdn.com/v4/letter/g/e95f7d/32.png) [@gunnergoz](https://boards.straightdope.com/u/gunnergoz)\ **Post date:** [August 27, 2012, 8:35am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/8 "2012-08-27T08:35:34Z")
> [@chacoguy](#): > > On I-15 in SLC, I was following a Trooper that turned on his overhead lights and began slowly weaving side-to-side. He eventually had all four lanes down to about 20mph. Then, he turned them off and we all went on our way. I assume that this was training for just such an event. I’ve seen California Highway Patrol officers do this too and according to the radio report I heard about the same time, they were apparently slowing us down so some debris on the freeway could be cleared about 2-3 miles ahead of where we were at the time. ---
**Author:** ![Heracles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heracles/32/487_2.png) [@Heracles](https://boards.straightdope.com/u/Heracles)\ **Post date:** [August 27, 2012, 9:16am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/9 "2012-08-27T09:16:16Z")
I’ve seen this in cases where the road is slippery because of ice or snow. (Granted, this isn’t the season in the northern hemisphere.) Maybe an oil slick on the road, or some bridge repair where speed needs to be limited for physical/vibration reasons. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [August 27, 2012, 11:34am UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/10 "2012-08-27T11:34:41Z")
I’ve seen this a couple times. In both cases it was a report of a wrong way driver on the interstate. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [August 27, 2012, 12:03pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/11 "2012-08-27T12:03:57Z")
It’s to provide a gap, a traffic break, due to something happening ahead. They don’t need to stop traffic completely, just make a few minutes’ space with no cars so something can be cleared up – maybe debris in the road, could be almost anything. ---
**Author:** ![Sigene](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sigene](https://boards.straightdope.com/u/Sigene)\ **Post date:** [August 27, 2012, 6:04pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/12 "2012-08-27T18:04:58Z")
I’ve seen it for stopped traffic ahead. This prevents 60 mile an hour cars all of the sudden coming up on 10 mile an hour traffic. Mayhem, accidents and death would occur. SO the cops were slowing the traffic in a controlled manner to prevent the sudden pile up when the faster cars suddenly come up on the slow or stopped cars. ---
**Author:** ![purplehorseshoe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/purplehorseshoe/32/2996_2.png) [@purplehorseshoe](https://boards.straightdope.com/u/purplehorseshoe)\ **Post date:** [August 27, 2012, 6:11pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/13 "2012-08-27T18:11:36Z")
> [@racer72](#): > > I’ve seen this a couple times. In both cases it was a report of a wrong way driver on the interstate. Nice. Around here, wrong-way drivers on the freeways a) get out there in the wee hours of pre-dawn, and b) kill a few folks along with themselves. Each damn time. (OP, I would’ve assumed funeral procession.) ---
**Author:** ![freckafree](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/freckafree/32/3050_2.png) [@freckafree](https://boards.straightdope.com/u/freckafree)\ **Post date:** [August 27, 2012, 8:05pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/14 "2012-08-27T20:05:42Z")
It was kind of an odd hour for a funeral – around 9:30 on a Sunday morning. Debris/construction seems likely. ---
**Author:** ![UncleRojelio](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/unclerojelio/32/3160_2.png) [@UncleRojelio](https://boards.straightdope.com/u/UncleRojelio)\ **Post date:** [August 27, 2012, 8:28pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/15 "2012-08-27T20:28:15Z")
I’ve seen it on I35 a couple of times. Both times it was to slow traffic before routing it off the interstate to go around construction. ---
**Author:** ![Sicks\_Ate](https://avatars.discourse-cdn.com/v4/letter/s/258eb7/32.png) [@Sicks\_Ate](https://boards.straightdope.com/u/Sicks_Ate)\ **Post date:** [August 27, 2012, 8:32pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/16 "2012-08-27T20:32:13Z")
Another case would be where a utility company is running a new line over the highway. It surprisingly only takes a few minutes, and a rolling shut-down would give them plenty of time. ---
**Author:** ![Skammer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/skammer/32/143_2.png) [@Skammer](https://boards.straightdope.com/u/Skammer)\ **Post date:** [August 27, 2012, 8:47pm UTC](https://boards.straightdope.com/t/under-what-circumstances-would-police-slow-but-not-stop-traffic/632768/17 "2012-08-27T20:47:11Z")
I saw it here once when the president flew in, they were creating a buffer for the motorcade driving from the airport to the city.