I've never understood the need for slip lanes before a roundabout. It seems like something that is added only to increase the capacity and speed of cars.
This is a big improvement from your original, good work.
My town is full of roundabouts and the only one that has a slip lane is the one that moves the highway off of Main St. That’s like the only good use case for it.
Large trucks for sure.and also, this isn't a standard roundabout configuration. The turns the slip lanes facilitate look like they'd be really sharp otherwise. I think they're warranted here
When a 2 lane roundabout reaches capacity the extra slip lane relieves congestion. It’s better than the alternative of a 3 lane roundabout, those are harder to navigate and causes significantly more minor accidents.
Ditto. If you take another go at it, I'd start from the perspective of imagining if you were on a A corner and wanted to get to the opposite corner, and what path you would take. To get kitty corner from the SW corner to the NW corner, people would just walk in places where traffic isn't anticipating pedestrians.
I'm not sure what radius you're keeping to that necessitates the slip lanes. And I don't know which routes need capability for trucks or buses. But those would drive up project cost by requiring land acquisition to implement.
I've seen roundabouts where the paths go up on bridges to a little centre area, then people can choose which one to go down. Maybe OP could add one of those? It eliminates the need for traffic light crossing too.
It is a nice idea, but stairs and ramps do reduce utility for sidewalk users who cannot make it up and down as easily, if at all, such as wheelchair and scooter users or anyone carrying a wagon, two wheeled cart, etc.
Fair point. Maybe both? Bridge for ease of use, and crossing for accessibility, but used a lot less because most people use the bridge? Also jaywalking would be much less of a problem because, again, bridge.
Idk, I just think those bridges are neat.
yep absolutely. you could install physical barriers there and you'd still get jaywalkers with this kind of setup. the psychological pain of walking yet another 5 minutes in the scorching sun is just too strong.
I didn’t add to the description, but the idea is to have bushes and low plants in the islands to discourage jaywalking. Also, the traffic circle has a brick raised flower bed to double as a barricade for cars who fly through the intersection.
The crosswalks are raised higher than the road and made of red brick, so that all cars approach will have to slow, regardless of a person waiting to cross or not.
I like the use of raised sidewalk-level crosswalks, it's just that their placement is just inconvenient enough that people will still take the shortcut despite the low bushes. Consider the path of least resistance and the desire paths that will form, then design around those paths.
That you are saying you need to deter Jay walking means it isn't pedestrian friendly. All paths are far longer, requiring significant detours to get to crossings. Some crossing scenarios are nightmares. This isn't friendly to anyone trying to get around on foot, and all is meant to increase car throughput. 'Pedestrian friendly' needs to mean more than 'we designed it so maybe you won't get hit by a car as we inconvenience you'
I think [this](https://imgur.com/gallery/j0uAE0e) would be more pedestrian friendly, if you added crosswalks in red. Make them raised crosswalks and make the slip lanes narrow with a truck apron to discourage speeding by drivers. If you look at modern american roundabout designs, you don't have to shy away from putting crossings near the entrances, exits of the 'bout.
Edit:
You can keep or get rid of the existing CW but I'd say keep them. Gives peds additional places to cross and warns drivers that they are entering a pedestrian space
You are forcing pedestrians to take a huge detour just to continue straight ahead. This is my main complaint with urban roundabouts and you've turned it up to 11 here, oof.
The top, left, and right crossings could be moved closer to the actual roundabout. Crossings that are far away from the main intersection increases vehicle speeds as cars have more length to get to faster speeds prior to the crosswalk.
You still missing the mark, and it's still just bad road design and not urban design at all. And it's definatly not pedestrain-friendly, just becouse it's technicaly possible to to cross it.
Check out examples of roundabouts from countries that use them regularly, like the UK. For one roundabouts don’t have slip roads so you can get rid of those weird partial connections and just focus on the roundabout itself.
Yeah, I don't understand why this looks so overcomplicated. Basically just slap a normal roundabout in there. If the area is particularly large underpasses can be used for pedestrians (assuming there are pedestrians).
Someone already mentioned it but here goes my take on it:
Imagine you’re a pedestrian coming from the bottom right and you wanna go straight. What do you need to do to achieve that?
You need to walk straight ahead, then turn right, walk a few meters, turn left, potentially wait for a light because there’s a slip lane that allows can to maintain speed and crossing with out one means exposing yourself to harm. Cross a decently sized thoroughfare, turn left walk a few meters east and finally turn back in the direction you actually wanted to go.
That’s a lot of work. Walkable areas need to slowdown traffic by design or pedestrians are exposed to drivers going fast. While roundabouts are good, their aim is to keep traffic flowing and that’s often at odds with making the area friendly to pedestrians (although the Netherlands does both fairly successfully).
My take on this intersection is that you should pick the two main thoroughfares and use a 4 way intersection. The street that’s left can merge before the intersection like the one shown here:
https://nacto.org/publication/urban-street-design-guide/intersections/complex-intersections/complex-intersection-analysis/
Well, everything. Just start learning about urbanism and urban design, from good (mostly modern) sources.
It's good that you try to figure out how to improve shit situation that you notice, and tgat you are open to criticism, but urbanism is more complex than rocket science and I assume you wouldn't design rocket for Moon landning in your free time and ask "what to improve".
Read some basics like "Human scale" by J. Ghel. Check out some good urbanism contests and you will get the basic idea what urbanism is.
Some Urban Planning and Design schools run competitive design competition.
My experience was that they were only open to current students at a small number of nearby schools. They only occasionally publish submissions, usually there is a big party with posters on the walls of the entry's like an art exhibition but for urban design.
I don't know if contest and competition have different meaning in this case. But what I was talking about was standard prodecure when for example city council want to change something in some place, so different urbanist studios send proposals and the best one is choosed. Most of them are small and boring, many of them are not even made by urbanist but by traffic engineers, but there's also a lot of interesting one.
Every bigger change or development should include some form of contest, same like most often big architectural projects are choosed as a result of some sort of contest. Often architectural and urbanist contests are combined into one project.
It's competition for given site that need to changed or developed. It could be as small as one crossing or as big as whole city. It's not annual chapionship for urbanist.
Thank you for your posts.
With out going through point by point, I'd encourage considering the perspective of existing business owners and road users, particularly where their land may be impacted. Also consider the intent of the design, presumably to encourage pedestrian access and amenities and how the design achieves this and what could be done to further enhance this outcome.
The road from the south east will have to connect to the east-west road in a t-junction. Then the rest of the junction can be made into a 4-legged intersection.
My earlier design was lacking and with the encouragement of the commenters, I have re-designed my original design.
Some features:
* Raised crosswalks offset from the intersection
* Bike / walk trails added
* Trees and plants
* Reduced traffic from 3 lanes to 2
* Clearer lane markings (although I think I could do better)
* Design to include multiple transportation options and users
Original design is here: [https://www.reddit.com/r/urbandesign/comments/1dmwbi2/i\_redesigned\_a\_horrible\_55\_way\_intersection\_in\_my/](https://www.reddit.com/r/urbandesign/comments/1dmwbi2/i_redesigned_a_horrible_55_way_intersection_in_my/)
it feels quite redundant with US designers to enlarge the existing intersection by creating a roundabout. Of course, it seems better in the first place. Yet such intersections are already an issue as it's time for us to solve the problem from its roots.
You won't get anything by subsidising newer, larger, more appropriate to traffic infrastructure, traffic will still be there (perhaps there will be more), bike usage will still be low, pedestrian traffic will still be obstructed etc..
In fact, you need to utterly reduce the surface cars take. Now imagine this roundabout without roads just paths, and what we can achieve, of course this is absolutely unrealistic at the moment, but such ideas are starting to grow here in Western Europe.
In my humble opinion, this project, no matter how good, really is no better than the concept of a highway interchange; namely a lost space uniquely built in the purpose to create a safe intersection, that is not natural – and even less pedestrian friendly.
Good graphic work nonetheless!
I agree. The graphic is well done! I don't want to criticize OP and there are certainly limitations regarding implementable adjustments. Sometimes what you want is not what politics or finance wants.
Still, my first thought was: this takes up an enormous amount of space and it still prioritizes car traffic.
Reduce car lanes to one per direction, add dedicated bus and bike lanes, any unused space can be effectively turned into green, open and friendly third spaces. You could fit a small soccer pitch in there.
Any pedestrian attempting to go in the north south or east west direction has to go a LONG way out of their way to use the designated crosswalks. That doesn’t seem very pedestrian
-friendly to me.
The scale cannot be right on this, the roundabout seems really big but is shrank down into this pretty small space.
This is not pedestrian friendly, you're in Houston, a very metropolitan area, there will be jaywalking everywhere. You also need to consider semi trucks going through this.
You need a much better design study/ traffic study to even get this before a committee. But it would be shot down pretty quickly when they see the anticipated cost of it.
Scale was hard, mostly because I’ve never really done this before. I did have a goal to make all driving lanes 10-12 feet across, normal USA road width. But yeah, that traffic circle does look big.
Those lane arrows don't seem right and the slip lanes probably take up more land than is necessary. If you have enough high speed traffic to warrant slip lanes you probably don't want them entering other lanes off the roundabout where drivers speed will likely be much lower. It's hard to tell from the scale however.
I'm trying to find a similar sized junction in the UK but I'm more leaning towards it being a gyratory - less uniform in shape and allowing for more complex road combinations than a roundabout - mixing "A" and "B" roads better
As a general rule I wouldn’t use Houston as a reference. You’re using a reference from a city that prioritizes driving over everything else so no surprise that’s what you get.
Also, that design in Houston doesn’t have slip lanes so I would get rid of yours.
What problem are you trying to solve with this redesign? Is there too much traffic congestion? Collisions with cars or pedestrians? Improving pedestrian infrastructure?
Sorry for the unrelated question but what software do you use for these overlays?
I need to do one for my community council and it would be cool if there were and “easy” way do to this.
Transportation engineer here, the existing condition is an absolute mess so I can definitely see why you'd want to rethink this. This design doesn't really work as a roundabout as is, and I have a few thoughts from a roundabout and roadway design perspective, that aren't necessarily the best from an urban design perspective. Ideally we'd remove some lanes and a leg, but I'll treat them as they are, wide urban arterials, and do my best within the constraints of the site.
N leg
- the entry angle is too sharp. Generally, the lane approaching the roundabout is at an angle of ~100-110 deg (90 deg in europe). Generally, roundabouts are designed so vehicles can comfortably enter and exit at about 30 km/h, but on this leg they would have to slow down quite a bit. The road approaching the roundabout is very straight, and this design doesn't really tell the drivers that they'll need to slow to enter the roundabout or stop for pedestrians. Someone unfamiliar might not realize how sharp the turn they have to make to enter the roundabout is. We want the design to be able to tell drivers what they should be doing, and make it uncomfortable to travel faster than we want them to! This would also cause issues for larger vehicles, as they need more room to make the turn without running over curbs.
W leg
- similar comment, vehicles have to make quite a sharp turn, slowing down in the roundabout and impacting the overall capacity of the system
- the exit lanes are too close to the entry from the north. I could forsee vehicles accidentally exiting through the N entry. Moving the whole roundabout to the NW would give more room between these two legs
E leg
- The entry is too straight, cars will be able to enter the roundabout at a high speed!
SE leg
- exit too sharp
- can probably do without a multi-lane exit here!
I think another option would be to create a dogbone/dual roundabout. The legs in the current design are too close to each other and could cause issues. This design splits the legs so that they can be designed in conformance with design standards. Every existing movement is maintained, and this will greatly improve safety for vehicles in the roundabout. The NW roundabout would probably require property acquisition in the parking lot of the building to the NW, and the SE roundabout may require property acquisition in the empty lot. Of course ped connectivity is going to be a challenge (as with a lot of roundabouts), but this design allows pedestrians to get around without too many detours, and minimizes street crossings.
https://i.imgur.com/62wZiLN.png
You obviously have a keen interest in roundabout design, keep it up :) the graphic looks great!
Thanks! This is some great input and insight. I had not considered entry speed.
Also, I attempted another [design](https://www.reddit.com/r/urbandesign/s/SRSaXkTqWe), wildly different than a traffic circle.
There’s also more information and background on the the intersection that I’ve found, where it has upwards of 34k cars passing through it a day (found the TxDOT AADT site).
I think I like this better. Now that i've seen the actual location it's a decently dense urban environment w/ transit, regular signalized intersections might be a better solution. Nicely done!
Now THATS what I like to see! I would add some protected bike lanes and easier/faster crossing for pedestrians that isn’t so far away from the roundabout (take inspiration from Dutch roundabouts), but this is far better than the previous design. Keep it up!
this looks terrifying to walk through tbh. never got the whole "roundabouts are better for pedestrians" thing. drivers rarely check their blind spot, let alone yield for pedestrians after going 60+ kms.
You should switch your goals and perspective, I’ve had the same issue making cities in Cities Skylines.
If you grew up in the US, then don’t do what you know and what’s comfortable. Look on google earth for inspiration, and think about what you’d like as a pedestrian.
It can’t be both pedestrian and car friendly. One negates the other, and that’s fine. My suggestion here is to make a small roundabout and reduce or remove the slip lanes.
The focus on car through put is honorable. You might consider pedestrian crossing bridges (with appropriate ramps) that go over raised center median barriers and other barriers to prevent jaywalking/lazy pedestrians trying to cut corners and interfering with car flow.
This is my two cents as a built environment student. Interactions with 5 roads are dangerous for both cars, cyclists and pedestrians. In the Netherlands we rarely have them for this very reason. I don’t know where this is and maybe a roundabout would be a great idea to calm traffic, but maybe consider the macro or meal scale of this intersection. Why are there 5 roads leading here? Why is there a 4 lane road coming from the right? Is it possible to make this a 4 way intersection by making in the roads interest earlier? If you can make it intersect earlier, you can keep it as a roundabout, or make a protected intersection that is also cycle friendly unlike roundabouts.
Look into Dutch Intersection Design. There's still a lot of road space that can be removed, and can be more pedestrian friendly.
Does the road from the bottom middle need to go right into the intersection? What impact would it make if it intersected the bottom right diagonal road at the corner?
Also, does the intersection need to be a roundabout? How much of the city's funds is needed to reclaim the private land for the road construction? Is it worth it?
I like that it's a roundabout but I hate everything else about this. Imagine being a human walking in the east West direction... It's a wholly horrific experience. And dangerous.
I absolutely must know what program is used to do this, everyone in my county hates the current intersections and being able to draft proposals like this would help immensely
This looks massively over-built. I doubt there is such a need to expropriate so much land. This looks like a highway interchange rather than a town intersection. There number of lanes can be cut as traffic will moving through more efficiently. You don’t need space for cars waiting for the light to change. Slowing approach speeds allows for a smaller circle. This inherently improves safety and allows the crosswalks to be pushed back to the centre. Raised crosswalks across the lower speed streets would act as a reminder for cars to yield to traffic already in the circle. The bottom two streets can merge before the circle simplifying the problem further. One of those streets is going to be dominant.
Could we keep the bike lanes on 20th / Cavalcade please? Perhaps even include protection and a buffer that meets the Houston IDM.
N Main was supposed to get bike lanes too between Boundary and Airline. This intersection is just beyond Airline, but this section needs the same road diet. If we're redesigning the intersection, it'd be good to include those facilities in the design.
Also can we include access for bikes to continue north on Studewood? That's currently how I get to the farmer's market and would like to keep that functionality.
I realize this is you having fun, but there is some existing functionality that was lost in your design.
All the city needs to do is make the bottom up and down road a one way going down and get rid of the neighborhood street going into the intersection. Then it's just a 4 way
I live for these type of posts. I do these kinda designs all of the time so it’s exciting to see someone get into it.
I will say, however, that this redesign isn’t pedestrian friendly. I mean really think about the kinds of places pedestrians flock to. Typically it’s places with very few cars and many things to look at/observe. Maybe scratch the roundabout altogether because it just seems to eat up more land than it’s worth and is going to create a highway like area.
I’d look into plaza-esq intersections somewhere like Paris, London, or NYC for inspiration. These cities have lots of pedestrian-oriented town squares/parks with one or two lane (max) going around them. If your goal is to make this intersection somewhere that people want to be, then you must reject the car-centric design mentality.
You got it! The world needs more passionate urbanists.
Also! I just want to add that if you’re familiar with this area, it can be really hard to redesign it in a pedestrian-friendly/different way because you most likely have experiences waiting in traffic and whatnot which clouds your ability to objectively redesign it!
Move the crosswalks closer, this will let cars go faster for longer and make less of a detour for pedestrians. Also, let business parking exit towards the roundabout as well as away, to both allow drivers to go whichever way and avoid harming the businesses.
This is about as pedestrian friendly as highway 401 in Toronto. In fact, I think the distance that pedestrians need to walk to cross 401 is shorter than the distance they need to walk to cross this roundabout.
The old one didn’t take pedestrians into account at all, this one makes them go way out of the way just to go in a straight line, while the cars get slip lanes to go as fast as possible?
By definition roundabouts are not pedestrian friendly. The point of roundabouts is to keep traffic moving freely. As traffic does not stop during the normal course of function, the hope is that the drivers will pay enough attention to pedestrians to actually yield to their crossings. That seems like a bit of a stretch in the US.
That’s not even considering the greater distances that the pedestrians are forced to travel as other posters have pointed out.
I've never understood the need for slip lanes before a roundabout. It seems like something that is added only to increase the capacity and speed of cars. This is a big improvement from your original, good work.
My town is full of roundabouts and the only one that has a slip lane is the one that moves the highway off of Main St. That’s like the only good use case for it.
Probably to accommodate large trucks making turns.
Large trucks for sure.and also, this isn't a standard roundabout configuration. The turns the slip lanes facilitate look like they'd be really sharp otherwise. I think they're warranted here
When a 2 lane roundabout reaches capacity the extra slip lane relieves congestion. It’s better than the alternative of a 3 lane roundabout, those are harder to navigate and causes significantly more minor accidents.
Seems very tempting to jaywalk across several points where the sidewalk paths detour to a crosswalk.
Ditto. If you take another go at it, I'd start from the perspective of imagining if you were on a A corner and wanted to get to the opposite corner, and what path you would take. To get kitty corner from the SW corner to the NW corner, people would just walk in places where traffic isn't anticipating pedestrians. I'm not sure what radius you're keeping to that necessitates the slip lanes. And I don't know which routes need capability for trucks or buses. But those would drive up project cost by requiring land acquisition to implement.
Very much so.
I've seen roundabouts where the paths go up on bridges to a little centre area, then people can choose which one to go down. Maybe OP could add one of those? It eliminates the need for traffic light crossing too.
It is a nice idea, but stairs and ramps do reduce utility for sidewalk users who cannot make it up and down as easily, if at all, such as wheelchair and scooter users or anyone carrying a wagon, two wheeled cart, etc.
Fair point. Maybe both? Bridge for ease of use, and crossing for accessibility, but used a lot less because most people use the bridge? Also jaywalking would be much less of a problem because, again, bridge. Idk, I just think those bridges are neat.
sink the roundabout and have the bridges be flat
yep absolutely. you could install physical barriers there and you'd still get jaywalkers with this kind of setup. the psychological pain of walking yet another 5 minutes in the scorching sun is just too strong.
Yeah, it’s pedestrian friendly by making them jaywalk/cross half a block away.
I didn’t add to the description, but the idea is to have bushes and low plants in the islands to discourage jaywalking. Also, the traffic circle has a brick raised flower bed to double as a barricade for cars who fly through the intersection. The crosswalks are raised higher than the road and made of red brick, so that all cars approach will have to slow, regardless of a person waiting to cross or not.
I like the use of raised sidewalk-level crosswalks, it's just that their placement is just inconvenient enough that people will still take the shortcut despite the low bushes. Consider the path of least resistance and the desire paths that will form, then design around those paths.
That you are saying you need to deter Jay walking means it isn't pedestrian friendly. All paths are far longer, requiring significant detours to get to crossings. Some crossing scenarios are nightmares. This isn't friendly to anyone trying to get around on foot, and all is meant to increase car throughput. 'Pedestrian friendly' needs to mean more than 'we designed it so maybe you won't get hit by a car as we inconvenience you'
This Looks made for cars ans for no one else. For older people with mobility issues this is like building à Chasm that cannot be crossed
I think [this](https://imgur.com/gallery/j0uAE0e) would be more pedestrian friendly, if you added crosswalks in red. Make them raised crosswalks and make the slip lanes narrow with a truck apron to discourage speeding by drivers. If you look at modern american roundabout designs, you don't have to shy away from putting crossings near the entrances, exits of the 'bout. Edit: You can keep or get rid of the existing CW but I'd say keep them. Gives peds additional places to cross and warns drivers that they are entering a pedestrian space
You are forcing pedestrians to take a huge detour just to continue straight ahead. This is my main complaint with urban roundabouts and you've turned it up to 11 here, oof.
The top, left, and right crossings could be moved closer to the actual roundabout. Crossings that are far away from the main intersection increases vehicle speeds as cars have more length to get to faster speeds prior to the crosswalk.
You still missing the mark, and it's still just bad road design and not urban design at all. And it's definatly not pedestrain-friendly, just becouse it's technicaly possible to to cross it.
What needs improvement?
Check out examples of roundabouts from countries that use them regularly, like the UK. For one roundabouts don’t have slip roads so you can get rid of those weird partial connections and just focus on the roundabout itself.
Yeah, I don't understand why this looks so overcomplicated. Basically just slap a normal roundabout in there. If the area is particularly large underpasses can be used for pedestrians (assuming there are pedestrians).
Someone already mentioned it but here goes my take on it: Imagine you’re a pedestrian coming from the bottom right and you wanna go straight. What do you need to do to achieve that? You need to walk straight ahead, then turn right, walk a few meters, turn left, potentially wait for a light because there’s a slip lane that allows can to maintain speed and crossing with out one means exposing yourself to harm. Cross a decently sized thoroughfare, turn left walk a few meters east and finally turn back in the direction you actually wanted to go. That’s a lot of work. Walkable areas need to slowdown traffic by design or pedestrians are exposed to drivers going fast. While roundabouts are good, their aim is to keep traffic flowing and that’s often at odds with making the area friendly to pedestrians (although the Netherlands does both fairly successfully). My take on this intersection is that you should pick the two main thoroughfares and use a 4 way intersection. The street that’s left can merge before the intersection like the one shown here: https://nacto.org/publication/urban-street-design-guide/intersections/complex-intersections/complex-intersection-analysis/
Well, everything. Just start learning about urbanism and urban design, from good (mostly modern) sources. It's good that you try to figure out how to improve shit situation that you notice, and tgat you are open to criticism, but urbanism is more complex than rocket science and I assume you wouldn't design rocket for Moon landning in your free time and ask "what to improve". Read some basics like "Human scale" by J. Ghel. Check out some good urbanism contests and you will get the basic idea what urbanism is.
Not OP, but what kind of urbanism contests exist? (Nerd alert) Sounds cool
Some Urban Planning and Design schools run competitive design competition. My experience was that they were only open to current students at a small number of nearby schools. They only occasionally publish submissions, usually there is a big party with posters on the walls of the entry's like an art exhibition but for urban design.
I don't know if contest and competition have different meaning in this case. But what I was talking about was standard prodecure when for example city council want to change something in some place, so different urbanist studios send proposals and the best one is choosed. Most of them are small and boring, many of them are not even made by urbanist but by traffic engineers, but there's also a lot of interesting one.
Every bigger change or development should include some form of contest, same like most often big architectural projects are choosed as a result of some sort of contest. Often architectural and urbanist contests are combined into one project. It's competition for given site that need to changed or developed. It could be as small as one crossing or as big as whole city. It's not annual chapionship for urbanist.
Thank you for your posts. With out going through point by point, I'd encourage considering the perspective of existing business owners and road users, particularly where their land may be impacted. Also consider the intent of the design, presumably to encourage pedestrian access and amenities and how the design achieves this and what could be done to further enhance this outcome.
The road from the south east will have to connect to the east-west road in a t-junction. Then the rest of the junction can be made into a 4-legged intersection.
My earlier design was lacking and with the encouragement of the commenters, I have re-designed my original design. Some features: * Raised crosswalks offset from the intersection * Bike / walk trails added * Trees and plants * Reduced traffic from 3 lanes to 2 * Clearer lane markings (although I think I could do better) * Design to include multiple transportation options and users Original design is here: [https://www.reddit.com/r/urbandesign/comments/1dmwbi2/i\_redesigned\_a\_horrible\_55\_way\_intersection\_in\_my/](https://www.reddit.com/r/urbandesign/comments/1dmwbi2/i_redesigned_a_horrible_55_way_intersection_in_my/)
You've still taken out parking for those buildings at the bottom, I have to say it'd be hella expensive. But I like it! I bet this was fun to make
Was thinking the same. He should design a parallel quite lane!
So many pedestrians would not follow those paths
it feels quite redundant with US designers to enlarge the existing intersection by creating a roundabout. Of course, it seems better in the first place. Yet such intersections are already an issue as it's time for us to solve the problem from its roots. You won't get anything by subsidising newer, larger, more appropriate to traffic infrastructure, traffic will still be there (perhaps there will be more), bike usage will still be low, pedestrian traffic will still be obstructed etc.. In fact, you need to utterly reduce the surface cars take. Now imagine this roundabout without roads just paths, and what we can achieve, of course this is absolutely unrealistic at the moment, but such ideas are starting to grow here in Western Europe. In my humble opinion, this project, no matter how good, really is no better than the concept of a highway interchange; namely a lost space uniquely built in the purpose to create a safe intersection, that is not natural – and even less pedestrian friendly. Good graphic work nonetheless!
I agree. The graphic is well done! I don't want to criticize OP and there are certainly limitations regarding implementable adjustments. Sometimes what you want is not what politics or finance wants. Still, my first thought was: this takes up an enormous amount of space and it still prioritizes car traffic. Reduce car lanes to one per direction, add dedicated bus and bike lanes, any unused space can be effectively turned into green, open and friendly third spaces. You could fit a small soccer pitch in there.
Any pedestrian attempting to go in the north south or east west direction has to go a LONG way out of their way to use the designated crosswalks. That doesn’t seem very pedestrian -friendly to me.
The scale cannot be right on this, the roundabout seems really big but is shrank down into this pretty small space. This is not pedestrian friendly, you're in Houston, a very metropolitan area, there will be jaywalking everywhere. You also need to consider semi trucks going through this. You need a much better design study/ traffic study to even get this before a committee. But it would be shot down pretty quickly when they see the anticipated cost of it.
Scale was hard, mostly because I’ve never really done this before. I did have a goal to make all driving lanes 10-12 feet across, normal USA road width. But yeah, that traffic circle does look big.
Those lane arrows don't seem right and the slip lanes probably take up more land than is necessary. If you have enough high speed traffic to warrant slip lanes you probably don't want them entering other lanes off the roundabout where drivers speed will likely be much lower. It's hard to tell from the scale however. I'm trying to find a similar sized junction in the UK but I'm more leaning towards it being a gyratory - less uniform in shape and allowing for more complex road combinations than a roundabout - mixing "A" and "B" roads better
I was trying to model it off of a similar 5 way traffic circle in Houston that is already in use. https://maps.app.goo.gl/ghaRtmfFq9DAqmQ8A?g_st=ic
As a general rule I wouldn’t use Houston as a reference. You’re using a reference from a city that prioritizes driving over everything else so no surprise that’s what you get. Also, that design in Houston doesn’t have slip lanes so I would get rid of yours.
As someone who drives on the other side of the road I'm going to need to sit down and look at this properly because my head's gucked
How do you enter that parking lot up right?
i would question whether high speed slip lanes, hugely set back crosswalks, and still fairly narrow sidewalks passes for “pedestrian friendly”
What problem are you trying to solve with this redesign? Is there too much traffic congestion? Collisions with cars or pedestrians? Improving pedestrian infrastructure?
The exit from the roundabout onto the western leg is very sharp and tight. very easy for cars To miss, or to hit the curb.
Sorry for the unrelated question but what software do you use for these overlays? I need to do one for my community council and it would be cool if there were and “easy” way do to this.
Just no. Close a street, lol. A dumbbell roundabout is way better than this
Very simple question but I’m not an urban designer or transport planner! What software did you use to produce this?
Transportation engineer here, the existing condition is an absolute mess so I can definitely see why you'd want to rethink this. This design doesn't really work as a roundabout as is, and I have a few thoughts from a roundabout and roadway design perspective, that aren't necessarily the best from an urban design perspective. Ideally we'd remove some lanes and a leg, but I'll treat them as they are, wide urban arterials, and do my best within the constraints of the site. N leg - the entry angle is too sharp. Generally, the lane approaching the roundabout is at an angle of ~100-110 deg (90 deg in europe). Generally, roundabouts are designed so vehicles can comfortably enter and exit at about 30 km/h, but on this leg they would have to slow down quite a bit. The road approaching the roundabout is very straight, and this design doesn't really tell the drivers that they'll need to slow to enter the roundabout or stop for pedestrians. Someone unfamiliar might not realize how sharp the turn they have to make to enter the roundabout is. We want the design to be able to tell drivers what they should be doing, and make it uncomfortable to travel faster than we want them to! This would also cause issues for larger vehicles, as they need more room to make the turn without running over curbs. W leg - similar comment, vehicles have to make quite a sharp turn, slowing down in the roundabout and impacting the overall capacity of the system - the exit lanes are too close to the entry from the north. I could forsee vehicles accidentally exiting through the N entry. Moving the whole roundabout to the NW would give more room between these two legs E leg - The entry is too straight, cars will be able to enter the roundabout at a high speed! SE leg - exit too sharp - can probably do without a multi-lane exit here! I think another option would be to create a dogbone/dual roundabout. The legs in the current design are too close to each other and could cause issues. This design splits the legs so that they can be designed in conformance with design standards. Every existing movement is maintained, and this will greatly improve safety for vehicles in the roundabout. The NW roundabout would probably require property acquisition in the parking lot of the building to the NW, and the SE roundabout may require property acquisition in the empty lot. Of course ped connectivity is going to be a challenge (as with a lot of roundabouts), but this design allows pedestrians to get around without too many detours, and minimizes street crossings. https://i.imgur.com/62wZiLN.png You obviously have a keen interest in roundabout design, keep it up :) the graphic looks great!
Thanks! This is some great input and insight. I had not considered entry speed. Also, I attempted another [design](https://www.reddit.com/r/urbandesign/s/SRSaXkTqWe), wildly different than a traffic circle. There’s also more information and background on the the intersection that I’ve found, where it has upwards of 34k cars passing through it a day (found the TxDOT AADT site).
I think I like this better. Now that i've seen the actual location it's a decently dense urban environment w/ transit, regular signalized intersections might be a better solution. Nicely done!
This is so incredibly badly designed. Imagine you want to walk straight? Too bad
What program are you using?
Now THATS what I like to see! I would add some protected bike lanes and easier/faster crossing for pedestrians that isn’t so far away from the roundabout (take inspiration from Dutch roundabouts), but this is far better than the previous design. Keep it up!
this looks terrifying to walk through tbh. never got the whole "roundabouts are better for pedestrians" thing. drivers rarely check their blind spot, let alone yield for pedestrians after going 60+ kms.
Would the slip lanes encourage drivers to go fast through the pedestrian crossings?
You should switch your goals and perspective, I’ve had the same issue making cities in Cities Skylines. If you grew up in the US, then don’t do what you know and what’s comfortable. Look on google earth for inspiration, and think about what you’d like as a pedestrian. It can’t be both pedestrian and car friendly. One negates the other, and that’s fine. My suggestion here is to make a small roundabout and reduce or remove the slip lanes.
The focus on car through put is honorable. You might consider pedestrian crossing bridges (with appropriate ramps) that go over raised center median barriers and other barriers to prevent jaywalking/lazy pedestrians trying to cut corners and interfering with car flow.
That to confusing
This is my two cents as a built environment student. Interactions with 5 roads are dangerous for both cars, cyclists and pedestrians. In the Netherlands we rarely have them for this very reason. I don’t know where this is and maybe a roundabout would be a great idea to calm traffic, but maybe consider the macro or meal scale of this intersection. Why are there 5 roads leading here? Why is there a 4 lane road coming from the right? Is it possible to make this a 4 way intersection by making in the roads interest earlier? If you can make it intersect earlier, you can keep it as a roundabout, or make a protected intersection that is also cycle friendly unlike roundabouts.
Look into Dutch Intersection Design. There's still a lot of road space that can be removed, and can be more pedestrian friendly. Does the road from the bottom middle need to go right into the intersection? What impact would it make if it intersected the bottom right diagonal road at the corner? Also, does the intersection need to be a roundabout? How much of the city's funds is needed to reclaim the private land for the road construction? Is it worth it?
Make it a peanut roundabout! 🥜
There is nothing pedestrian friendly about it
No ma, trust me people arent gonna do 500 meters to go to a crosswalk, but i think youve already herd it, good look tho :)
add separated bike lanes
I like that it's a roundabout but I hate everything else about this. Imagine being a human walking in the east West direction... It's a wholly horrific experience. And dangerous.
I absolutely must know what program is used to do this, everyone in my county hates the current intersections and being able to draft proposals like this would help immensely
This looks massively over-built. I doubt there is such a need to expropriate so much land. This looks like a highway interchange rather than a town intersection. There number of lanes can be cut as traffic will moving through more efficiently. You don’t need space for cars waiting for the light to change. Slowing approach speeds allows for a smaller circle. This inherently improves safety and allows the crosswalks to be pushed back to the centre. Raised crosswalks across the lower speed streets would act as a reminder for cars to yield to traffic already in the circle. The bottom two streets can merge before the circle simplifying the problem further. One of those streets is going to be dominant.
It’s been neat seeing you refine this intersection design over time.
If you don’t want to take out parking at the adjacent structures, I think a double mini-roundabout at an angle would be preferable.
Could we keep the bike lanes on 20th / Cavalcade please? Perhaps even include protection and a buffer that meets the Houston IDM. N Main was supposed to get bike lanes too between Boundary and Airline. This intersection is just beyond Airline, but this section needs the same road diet. If we're redesigning the intersection, it'd be good to include those facilities in the design. Also can we include access for bikes to continue north on Studewood? That's currently how I get to the farmer's market and would like to keep that functionality. I realize this is you having fun, but there is some existing functionality that was lost in your design.
pedestrian friendly is a stretch
Need a pedestrian flyover
Kill the one street and figure out how a 👯♀️2 way roundabout actually works
Maybe a peanut round about could decrease land coverage and improve corner angles to bring the ped crossings in closer and lose the slip lanes.
All the city needs to do is make the bottom up and down road a one way going down and get rid of the neighborhood street going into the intersection. Then it's just a 4 way
I live for these type of posts. I do these kinda designs all of the time so it’s exciting to see someone get into it. I will say, however, that this redesign isn’t pedestrian friendly. I mean really think about the kinds of places pedestrians flock to. Typically it’s places with very few cars and many things to look at/observe. Maybe scratch the roundabout altogether because it just seems to eat up more land than it’s worth and is going to create a highway like area. I’d look into plaza-esq intersections somewhere like Paris, London, or NYC for inspiration. These cities have lots of pedestrian-oriented town squares/parks with one or two lane (max) going around them. If your goal is to make this intersection somewhere that people want to be, then you must reject the car-centric design mentality. You got it! The world needs more passionate urbanists. Also! I just want to add that if you’re familiar with this area, it can be really hard to redesign it in a pedestrian-friendly/different way because you most likely have experiences waiting in traffic and whatnot which clouds your ability to objectively redesign it!
Move the crosswalks closer, this will let cars go faster for longer and make less of a detour for pedestrians. Also, let business parking exit towards the roundabout as well as away, to both allow drivers to go whichever way and avoid harming the businesses.
This is about as pedestrian friendly as highway 401 in Toronto. In fact, I think the distance that pedestrians need to walk to cross 401 is shorter than the distance they need to walk to cross this roundabout.
The old one didn’t take pedestrians into account at all, this one makes them go way out of the way just to go in a straight line, while the cars get slip lanes to go as fast as possible?
Yes, maybe this is pedestrian-friendly there in the USA
Yup, it’s quite frustrating to live in a community that is very car centric. Reality forces dreams to be curbed.
What software are you using?
By definition roundabouts are not pedestrian friendly. The point of roundabouts is to keep traffic moving freely. As traffic does not stop during the normal course of function, the hope is that the drivers will pay enough attention to pedestrians to actually yield to their crossings. That seems like a bit of a stretch in the US. That’s not even considering the greater distances that the pedestrians are forced to travel as other posters have pointed out.
I like this version a lot more! Send it to your local city townhall as a suggestion or sth.
This is worse, it only considers car flow, zero consideration for pedestrians.
Remove all cars. Every urban design that still incorporates personal cars is an automatic failure.