[kelnos]

> without any workers or equipment in sight, ever. [...] Everyone can name a stretch of highway they've seen treated this way

I think there's an inherent bias here. Each individual is not seeing that section of road 24/7. At most they see it for a few minutes (or perhaps a little longer, if traffic slows enough), maybe once or at most a few times per day. That's a very small fraction of the day, and work could be occurring during other parts of the day, possibly even at night. Safety might require that they do the work when there are few cars driving by, but the nature of the work might be such that they can't unblock the lanes during the day.

I get that this isn't satisfying, but often reality isn't. And I have no doubt that there are plenty of mismanaged projects around the world where there are lots of delays, and long stretches of time when nothing is getting done. But I think it's incorrect to believe that nothing is getting done just because a few people you know drive by the area a few times a day and don't see anyone working.

[jcrawfordor]

Very common on US freeways for work to be performed at night even though it's barricaded during the day. The barricades are to keep traffic off of work in progress, actual work may require additional lane closures, traffic disruptions as trucks enter and exit, and safety scales with traffic volumes. Keep in mind, for example, that the permanent closure area is not typically large enough to stage equipment. That means that equipment and supplies need to be moved in and out of a laydown yard during work, which is very dangerous during normal traffic volume.

It also tends to be the case that price is reduced by scheduling work across multiple contractors with independent scheduling... so the cost savings come at the expense of idle periods while waiting for the next contractor to be available. Not a totally unaddressable problem but ultimately fast and cheap are, as usual, opposing requirements. Funding politics can also play a role here, very common that larger projects don't have all of their funding available at once, so they may sit idle while waiting for the next set of funds.