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Seems like safety won't be an issue in the future with self driving cars, because they will all be standing still in a traffic when we all use them (self.showerthoughts)
submitted 4 months ago by to c/showerthoughts@lemmy.world
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So self driving car brands are currently in the process of offering subscription based self driving features.

Soon these subscriptions will be cheap enough for everybody to abandon public transport and get into their self driving cars instead.

This means that everybody will be in their cars and it will create the biggest traffic jam in human history!

And finally, self-driving cars will be totally safe and able to drive completely unsupervised! While standing still in traffic going an average of 5 km/h...

It will be beautiful (/s)

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[–] 1 point 4 months ago (1 child)

but after that you’re right back to “just one more lane, bro!

Since you stated that you are a traffic engineer, quick question for you. Are more lanes all together or more lanes separate better?

What I mean is are you better off with 1 highway that has 4 lanes in each direction or 2 highways that each have 2 lanes in each direct. Same total lanes, but split up differently? It seems like adding more lanes to a congested road just makes a bigger mess; a problem in any lane seems to propagate through all lanes.

I know it's a lot more complicated than just building a parallel road, but (in my area at least) the lack of alternate routes is frustrating. The entire highway turns into a parking lot if there's a crash. I also see a lot of near misses due to lane flanking: car in lane A and car in lane C both want in lane B at the same time. More lanes = more likely for this to happen.

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  • [–] 4 points 4 months ago

    (Disclaimer: I am a traffic engineer in the sense that I have a degree in it and have done it professionally, but I got disillusioned and bailed in favor of software engineering so I'm not hugely experienced. Think EIT, not PE.)

    That is a very good question I don't have a good answer for, and have wondered myself.

    First of all, it's more in the wheelhouse of urban planning than it is traffic engineering (being concerned with an entire area rather than one road at a time), so there's that. But on the other hand, urban planners are more concerned with issues like land use and aren't necessarily analyzing traffic flows the way traffic engineers do. I'm not sure the specific kind of comprehensive designing you're hoping for actually gets done often enough.

    That said, it seems like the prevailing opinion (when it comes to the city street network, as opposed to freeways) is that having a hierarchy of functional classification, with the traffic being funneled from local streets to collectors to arterials, is the preferred way to go. Traffic engineers like it because they can (theoretically) design the arterial to provide better performance in terms of mobility while worrying less about pesky things like access and placemaking, and NIMBY homeowners like it because it gets the thru-traffic off their street.

    Personally, I'm actually pretty skeptical of that, from an urbanist and "recovering engineer" perspective. I think it could be better if traffic were evenly distributed across blocks, such that (a) the lack of true high-capacity/high-speed corridors would discourage driving altogether and provide better placemaking and urbanism, and (b) each street's "fair share" would hopefully be low and slow enough that it would be acceptably safe for cyclists/pedestrians/kids playing in the street etc. Basically, I think "worse" could actually be better, once you realign your goals away from moving traffic as quickly as possible and towards making a good place to live.

    When it comes to freeways specifically, I'm not sure anywhere does parallel freeway corridors unless the area served by each justifies a freeway in its own right. But if anywhere does, it'd be Texas, home of the infamous Katy Freeway...

    Katy Freeway

    ...and other extensive use of frontage roads. I actually learned about that just the other day from this recent Road Guy Rob video, which honestly might answer your question better than my screed above did, now that I think about it. (Sorry for not leading with that, but I've got too much sunk cost fallacy to delete what I wrote now.)

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