Now I have a roundabout right in front of my child's daycare. Due to the traffic rules surrounding that roundabout (Germany), it'll be impossible for him to cross that safely without me being very hands-on.
All these systems are completely made to get another 2 % of efficiency for cars, while massively sacrificing walkability and bikeability. I am not a fan anymore.
I still think roundabouts are a great idea for more rural road junctions. They're much safer, and I suspect more efficient, than cross roads controlled by traffic lights. I was driving around Toronto last year and the amount of stopping and starting at traffic lights you have to do is infuriating.
Regarding your second point, if you mean a car changing lanes from an inner lane to an outer lane, it does need to yield to everyone in that outer lane. This includes yielding to cyclists whose trajectory would intersect with the car. Again, the same applies to all traffic.
Around here (suburban DC,USA) they’re exclusively used where two massive highways intersect. Usually one 6+ lane interstate with a 4+ lane state highway. And the interchange itself is enormous - long, wide, noisy, stinky with fumes.
Any pedestrian traffic is carried by a physically separate walking path. Not “local” sidewalks.
It’s a very car-centric design. But where the highways already existed, it’s at least a traffic improvement with no reduction in pedestrian access (which was usually nil before the interchange, and improved by addition of separate walkway during construction).
Though, having lived in Utah and having dined on I-5 up and down the west coast, the idea of finding oneself walking right over one, as if a car, isn't as far out there as some may believe.
I'm guessing the diverging diamond replaced a bridge with two intersections? In which case, the oddity of the diverging diamond might at least serve as a traffic calming measure. Even when you get used to it, switching travel directions is uncomfortable for drivers which can force them to be a bit more cautious.
That said, the new sidewalks in the satellite photos are probably a big improvement over the old ones (if there were any). They at least have some small curbs and ~2-4 feet of separation from the cars traveling at high speeds along the stroad. If you look at the sidewalks to the west, where there's no separation from the stroad, they're...well, at least not that? But for the most part, sidewalks alongside stroads are just an afterthought.
Oof.
The particular case of two highways intersecting is one thing. Go ahead and have your diverging diamond interchange there. However, I don't believe Interstate-Interstate-Crossings are the most common use in the US? See for example https://wsdot.wa.gov/travel/traffic-safety-methods/diverging.... Three crossings, none are between two interstates? Or am I misreading this?
I actually believe it comes down to this: You only need the diverging diamond interchange if you build a highway in tight spaces, such as inside cities. In particular you want them on heavily frequented entries/exits that would otherwise let traffic back up into the cities. Thus, the interchange is at or close to a location with a lot of important destinations, otherwise you wouldn't build it there.
Not having that interchange then open to traffic other than cars then clearly makes it harder to cross the highway at these places. You'll have to go up or down each of the roads until you hit an over- or underpass or crossing. In my experience, in the US, this is generally very far - as of course everything is already bigger than in other places because of parking lots.
Here's a new example that opened a few years ago... https://www.google.com/maps/place/Haymarket,+VA+20169/@38.81...
It handles the intersection of a busy interstate and a busy local highway/stroad.
Here's a new interchange just down the road from the first, same interstate, but even busier highway. Instead of a diverging diamond, it's a bowl of spaghetti.
https://www.google.com/maps/@38.848214,-77.4319326,1404m/dat...
And the infamous "Springfield Mixing Bowl" that's the bane of suburban DC/VA commuter's existence... https://www.google.com/maps/@38.7874973,-77.1801693,4741m/da...
Two massive interstates, plus interchanges with busy local stroads in close proximity.
I mean adding zebra-crossing would be better, but you can combine them with a roundabout, can't you?
I do agree that cars are a big problem. I wonder if we should tax them higher to properly price in their negative externalities. (And Germany already has a lot higher taxes on driving than eg the US.)
A simple cross intersection controlled by traffic signals.
Yeah, I know I'm gonna get an imperial shit-ton of downvotes for daring to suggest traffic signals, but they are simple and involve traffic coming to a complete stop at the intersection.
Simplicity is a virtue, and it's why traffic signals still reign supreme at least here in the USA.
Example: https://hdp-au-prod-app-shel-letschatshellharbour-files.s3.a...
Maybe the light enforced meditation time would assist drivers like that in reëvaluating their life choices.
Crossing a red light, sometimes even to make way for emergency cars, will earn you 3 demerit points, which gets you over 23% to 13 points and losing your license.
Now it might not seem so dumb to wait 30 seconds, even if it is 3 AM and the road --seems empty.
And for the record, “dumb” is your word not mine. People make choices based on their own situational perception. I strive never to mute a person’s lived experience.
The issue is that roundabouts generally only have a yield sign, which means cars are rarely at a standstill. This complicates pedestrians crossing the street.
Those seem to be an American thing? They aren't really in use in Germany.
And, in practice, people don't stop at stop signs. So this wouldn't help the original commentor's child survive.
Combine with raised pedestrian crossings and you have natural speed bumps reducing car speeds even further at the potential point of conflict.
Though I guess a zebra crossing would be simpler.
> Simplicity is a virtue, and it's why traffic signals still reign supreme at least here in the USA.
Roundabouts are much simpler, aren't they? They don't even have any moving parts.
With traffic signals, much of the cognitive load is offloaded from the driver. The driver only needs to pay attention to the signal and whether there are any hazards in his planned direction of travel. A four-way stop signed intersection can produce similarly simpler results compared to roundabouts.
With roundabouts the driver needs to count or be thoroughly aware of his planned exit, maintain an appropriate speed and curving direction of travel throughout the roundabout, yield or not yield according to traffic at any given moment, and obviously whether any hazards are ahead or near him. That is not simple.
You don't want them to drift off mentally and blindly trust the traffic light?
Burdening a driver with more (arguably unnecessary) cognitive load is not a good idea.
I have several roundabouts near me and most have prioritized pedestrian crosswalks on all exits (Zebrastreifen), some with extra room for cars to break when they notice pedestrians. The ones lacking pedestrian prioritization are outside the city or in industrial zones.
Zebrastreifen would be a nice thing. However, around here it's either canonical rules for all roundabouts or even yield signs for non-car traffic. (I suppose they're only really valid for bikes which share the sidewalk, though? No idea, I just yield anyhow.)
Zebrastreifen would certainly be safer than nothing. My experience, though, is, that a sufficient number of drivers is already confused or overwhelmed by basic roundabout rules and don't even see them. A traffic light simplifies everything at the cost of a bit less efficiency for cars.
[0] https://google.com/maps/@37.783523,-121.2341659,569m/data=!3...
In order to have any chance of crossing the roundabout in rush-hour traffic, I have to accept cars yielding and cross onto the middle island between exit and entry. The alternative to not crossing for yielding cars would be to wait until the roundabout is empty, which essentially never happens.
However, the island is tiny. My son's bike just about fits, mine does not even fit remotely. Thus I now have to teach him to stop exactly on that island (Which, admittedly, he does very well. I don't have the confidence, though, that he'll be able to 100 % of the time. Driving past once while a car also goes by has a significant chance of causing an accident, as there is no space to evade for anybody.)
This whole ordeal we have to do twice every day. It's not totally unmanagable, but a crossing with traffic lights is so much safer than these maneuvers, that include communicating and trusting cars that they know the rules as well and understand what you're about to do.