A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
I like the idea of a 2 phase traffic light: one pedestrian phase where all cars are stopped, and then a cars phase where the intersection acts as a regular unsignalized intersection. For a roundabout you could even only have traffic lights at the entry points for cars, and just time the lights so that the roundabout would generally be expected to be empty by the time pedestrians get the green light. Alternatively, exiting cars could get a flashing red during the pedestrian phase.
I know that many US intersections use the unsignalized phase at night, where (I am assuming) you can activate the pedestrian phase by pressing the button, but are there any examples of intersections that solely use the traffic light as a pedestrian safety device without ever having protected phases for cars, and are there signalized roundabouts that aren't horrible traffic circles?
1. It's harder to get into a roundabout if you begin stopped.
2. It shouldn't be hard to cross as a pedestrian, as you're effectively crossing a series of one-way roads due to the medians. Just cross when it's clear. It may take longer, but it's not more dangerous.
3. If there are no signals on the exiting approaches, that won't solve your proposed pedestrian problem. If there are (including flashing red), the roundabout will back up, which is a major problem.
Quote from: yand on August 28, 2021, 12:09:26 AM
A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
I like the idea of a 2 phase traffic light: one pedestrian phase where all cars are stopped, and then a cars phase where the intersection acts as a regular unsignalized intersection. For a roundabout you could even only have traffic lights at the entry points for cars, and just time the lights so that the roundabout would generally be expected to be empty by the time pedestrians get the green light. Alternatively, exiting cars could get a flashing red during the pedestrian phase.
I know that many US intersections use the unsignalized phase at night, where (I am assuming) you can activate the pedestrian phase by pressing the button, but are there any examples of intersections that solely use the traffic light as a pedestrian safety device without ever having protected phases for cars, and are there signalized roundabouts that aren't horrible traffic circles?
You're incorrect on your assumptions. Many states have been changing over and leaving the traffic lights operational at night. For the intersections that aren't, they are in flash mode all night. A pedestrian can't activate them by pushing the button.
Not sure what you mean by not having a protected phase for cars, but there are traffic lights used just for pedestrian crossings.
Part of the purpose of roundabouts is a cheaper alternative to traffic lights. If traffic lights are going to be used for pedestrian crossings, then don't even bother with the roundabout at that point and make it a regular intersection.
Quote from: 1 on August 28, 2021, 06:05:40 AM
1. It's harder to get into a roundabout if you begin stopped.
2. It shouldn't be hard to cross as a pedestrian, as you're effectively crossing a series of one-way roads due to the medians. Just cross when it's clear. It may take longer, but it's not more dangerous.
3. If there are no signals on the exiting approaches, that won't solve your proposed pedestrian problem. If there are (including flashing red), the roundabout will back up, which is a major problem.
I think 1 lane roundabouts are certainly safe to cross, multi lane roundabouts may be a bit trickier unless you add islands between the same direction lanes.
The point of a flashing red on the exits and solid red on the entrance is to allow the roundabout to empty at a slower rate while keeping pedestrians safe, so it won't necessarily back up. Then because after the pedestrian phase the light turns flashing yellow or green for everyone at the same time, it shouldn't be hard to get the roundabout into a free flowing condition again. The periodic interruptions would also allow slower trucks to enter busy roundabouts so they aren't waiting 10 minutes at a busy roundabout.
Quote from: jeffandnicole on August 28, 2021, 08:07:42 AM
Quote from: yand on August 28, 2021, 12:09:26 AM
A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
I like the idea of a 2 phase traffic light: one pedestrian phase where all cars are stopped, and then a cars phase where the intersection acts as a regular unsignalized intersection. For a roundabout you could even only have traffic lights at the entry points for cars, and just time the lights so that the roundabout would generally be expected to be empty by the time pedestrians get the green light. Alternatively, exiting cars could get a flashing red during the pedestrian phase.
I know that many US intersections use the unsignalized phase at night, where (I am assuming) you can activate the pedestrian phase by pressing the button, but are there any examples of intersections that solely use the traffic light as a pedestrian safety device without ever having protected phases for cars, and are there signalized roundabouts that aren't horrible traffic circles?
You're incorrect on your assumptions. Many states have been changing over and leaving the traffic lights operational at night. For the intersections that aren't, they are in flash mode all night. A pedestrian can't activate them by pushing the button.
Not sure what you mean by not having a protected phase for cars, but there are traffic lights used just for pedestrian crossings.
Part of the purpose of roundabouts is a cheaper alternative to traffic lights. If traffic lights are going to be used for pedestrian crossings, then don't even bother with the roundabout at that point and make it a regular intersection.
Other benefits of roundabouts include safety and throughput, and the addition of pedestrian protection would allow them to maintain these benefits while improving the usability in areas where there are more pedestrians. There would still be savings with the addition of a traffic light to the roundabout since you don't need to install or maintain pressure plates etc. if the traffic light is button activated and flashing during car phase.
I think in general pedestrians should be able to turn traffic lights in flash mode to solid red by pushing the button. I am thinking of higher speed intersections with maybe not that much car traffic but you still want a better level of safety for pedestrians crossing it.
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
I feel like if you block an exit but not all the entrances, that would lead to the roundabout backing up. Although I do see how that could lead to needless waiting if the cars are entering and exiting on crossings where there are no waiting pedestrians. I suppose one way to solve this is to increase complexity with lane wise traffic lights. For example if a pedestrian is crossing on the right, then only allow cars in the left lane going straight/left to enter.
As long as roundabout entrances are simple yield signs, pedestrian safety will always be an issue at busier roundabouts. That said, putting up traffic lights or HAWKs (I hate HAWKs with a passion) would complicate the intersection.
I would think some form of RRFB would suffice.
Quote from: yand on August 28, 2021, 10:53:11 AM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
I feel like if you block an exit but not all the entrances, that would lead to the roundabout backing up. Although I do see how that could lead to needless waiting if the cars are entering and exiting on crossings where there are no waiting pedestrians. I suppose one way to solve this is to increase complexity with lane wise traffic lights. For example if a pedestrian is crossing on the right, then only allow cars in the left lane going straight/left to enter.
I don't think I've ever read a road improvement summary or story trying to resolve an issue that contained the words "to solve this is to increase complexity"...
Quote from: 1 on August 28, 2021, 06:05:40 AM
2. It shouldn't be hard to cross as a pedestrian, as you're effectively crossing a series of one-way roads due to the medians. Just cross when it's clear. It may take longer, but it's not more dangerous.
This is true for single-lane roundabouts, but there is some inherent safety issues with larger multi-lane roundabouts when it comes to crossing as a pedestrian. Even if it's a series of one-way streets, you have to ensure that both lanes stop at each leg. With slip lanes (which are added far too often at roundabouts), that can sometimes mean crossing four, five, or even six different legs just to get to the far side (and just as many lanes, if not many more). Compare this to a large intersection, even with slip lanes, where the crossings are signalized (better for those with disabilities), and the slip lanes are almost never more than one lane (more than that are usually signalized).
As an examples to accompany my above post, even if it is an extreme example, let's look at this roundabout in Carmel, IN (E 116 St @ Hazel Dell Pkwy).
No signals. Cool for cars, sure. But for pedestrians, this is a nightmare. At a minimum, at least four lanes of traffic have to stop to let you go, and who knows how long that will take.
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
(https://www.dronegenuity.com/wp-content/uploads/2018/03/carmel-IN-roundabout-10.jpg)
(image source: https://www.dronegenuity.com/projects/carmel-indiana-roundabout/)
Quote from: jakeroot on August 28, 2021, 12:05:11 PM
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
11 isn't much more than 8, which is what a typical intersection would require.
Quote from: jakeroot on August 28, 2021, 12:05:11 PM
As an examples to accompany my above post, even if it is an extreme example, let's look at this roundabout in Carmel, IN (E 116 St @ Hazel Dell Pkwy).
No signals. Cool for cars, sure. But for pedestrians, this is a nightmare. At a minimum, at least four lanes of traffic have to stop to let you go, and who knows how long that will take.
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
(https://www.dronegenuity.com/wp-content/uploads/2018/03/carmel-IN-roundabout-10.jpg)
(image source: https://www.dronegenuity.com/projects/carmel-indiana-roundabout/)
Actually, 13 lanes. Crossing from the left towards the parking lot: 2 lanes, 2 lanes, 2 lanes, then from the parking lot to the right: 2 lanes, 2 lanes, 3 lanes.
Quote from: 1 on August 28, 2021, 12:11:00 PM
Quote from: jakeroot on August 28, 2021, 12:05:11 PM
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
11 isn't much more than 8, which is what a typical intersection would require.
Yes, but typical intersections have signals, with lights. Being able to stop traffic completely (plus all of the other ADA benefits, like crossing sounds or LPIs) is going to be an overall better experience for those on foot.
Someone in a wheelchair, using a walker or cane, or even being blind...they're going to have superior experiences at signalized crossings. Even with twice as many lanes, I would argue.
Regular intersections often have yielding turns across the crosswalk (improved with the LPI), but I would still rather have a couple lanes yielding to me while in a signalized crosswalk over hoping that as many as *13 lanes* (thanks
jeffandnicole) stop for me.
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Quote from: Revive 755 on August 28, 2021, 12:30:23 PM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Pedestrian underpasses are the ideal solution, but many people in lower density regions perceive them as crime holes due to lack of sight lines and foot traffic.
A far enough crossing where drivers don't have to manage both navigating the roundabout and looking for pedestrians at the same time is also a safe solution, especially for crossing cyclists. If you make pedestrians go out of their way though, they may instead try to jaywalk.
The traffic light is an attempt to balance these factors.
Quote from: yand on August 28, 2021, 01:05:09 PM
Quote from: Revive 755 on August 28, 2021, 12:30:23 PM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Pedestrian underpasses are the ideal solution, but many people in lower density regions perceive them as crime holes due to lack of sight lines and foot traffic.
A far enough crossing where drivers don't have to manage both navigating the roundabout and looking for pedestrians at the same time is also a safe solution, especially for crossing cyclists. If you make pedestrians go out of their way though, they may instead try to jaywalk.
The traffic light is an attempt to balance these factors.
It depends on a pedestrian's destination. If they are going straight across, walking down the road takes them out of their way. But if they're turning left or right, the mid-block crossing actually can take less time.
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
Quote from: jeffandnicole on August 28, 2021, 01:10:56 PM
Quote from: yand on August 28, 2021, 01:05:09 PM
Quote from: Revive 755 on August 28, 2021, 12:30:23 PM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Pedestrian underpasses are the ideal solution, but many people in lower density regions perceive them as crime holes due to lack of sight lines and foot traffic.
A far enough crossing where drivers don't have to manage both navigating the roundabout and looking for pedestrians at the same time is also a safe solution, especially for crossing cyclists. If you make pedestrians go out of their way though, they may instead try to jaywalk.
The traffic light is an attempt to balance these factors.
It depends on a pedestrian's destination. If they are going straight across, walking down the road takes them out of their way. But if they're turning left or right, the mid-block crossing actually can take less time.
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
I assume roundabouts that currently have close intersection crossings are this way because the engineers/planners did their due diligence.
Quote from: yand on August 28, 2021, 01:42:19 PM
Quote from: jeffandnicole on August 28, 2021, 01:10:56 PM
Quote from: yand on August 28, 2021, 01:05:09 PM
Quote from: Revive 755 on August 28, 2021, 12:30:23 PM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Pedestrian underpasses are the ideal solution, but many people in lower density regions perceive them as crime holes due to lack of sight lines and foot traffic.
A far enough crossing where drivers don't have to manage both navigating the roundabout and looking for pedestrians at the same time is also a safe solution, especially for crossing cyclists. If you make pedestrians go out of their way though, they may instead try to jaywalk.
The traffic light is an attempt to balance these factors.
It depends on a pedestrian's destination. If they are going straight across, walking down the road takes them out of their way. But if they're turning left or right, the mid-block crossing actually can take less time.
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
I assume roundabouts that currently have close intersection crossings are this way because the engineers/planners did their due diligence.
From what I see nearby, it is more like designers read some newspaper articles about roundabout greatness and didn't give a second thought to anything else.
Quote from: yand on August 28, 2021, 01:42:19 PM
Quote from: jeffandnicole on August 28, 2021, 01:10:56 PM
Quote from: yand on August 28, 2021, 01:05:09 PM
Quote from: Revive 755 on August 28, 2021, 12:30:23 PM
Quote from: SkyPesos on August 28, 2021, 10:28:55 AM
I've seen HAWK signals used at busier roundabouts to allow pedestrian crossings, but not sure if a full traffic signal setup for all sides is needed, as it would sort of defeat one of the selling points of a roundabout.
The roundabout at 14th Street and Superior Street in Lincoln, NE (https://goo.gl/maps/1Lk9EadgfZUiNSjw8) has signalized pedestrian crossings on two of the legs. The other two legs are handled by pedestrian underpasses.
Pedestrian underpasses are the ideal solution, but many people in lower density regions perceive them as crime holes due to lack of sight lines and foot traffic.
A far enough crossing where drivers don't have to manage both navigating the roundabout and looking for pedestrians at the same time is also a safe solution, especially for crossing cyclists. If you make pedestrians go out of their way though, they may instead try to jaywalk.
The traffic light is an attempt to balance these factors.
It depends on a pedestrian's destination. If they are going straight across, walking down the road takes them out of their way. But if they're turning left or right, the mid-block crossing actually can take less time.
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
I assume roundabouts that currently have close intersection crossings are this way because the engineers/planners did their due diligence.
From you, the OP. Literally, the very first sentence you wrote:
Quote from: yand on August 28, 2021, 12:09:26 AM
A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
Quote from: jeffandnicole on August 28, 2021, 02:03:34 PM
Quote from: yand on August 28, 2021, 01:42:19 PM
Quote from: jeffandnicole on August 28, 2021, 01:10:56 PM
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
I assume roundabouts that currently have close intersection crossings are this way because the engineers/planners did their due diligence.
From you, the OP. Literally, the very first sentence you wrote:
Quote from: yand on August 28, 2021, 12:09:26 AM
A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
in terms of traffic analysis to determine which area has the highest demand for crossings. pedestrian safety is poor in this country in general, doesn't mean they didn't do due diligence in other aspects of planning.
Quote from: yand on August 28, 2021, 02:29:03 PM
Quote from: jeffandnicole on August 28, 2021, 02:03:34 PM
Quote from: yand on August 28, 2021, 01:42:19 PM
Quote from: jeffandnicole on August 28, 2021, 01:10:56 PM
Much like deciding how many through lanes and turn lanes are needed, seeing where peds would be coming from and going to should require a lot more analysis than just sticking a crossing as close to a roundabout as possible.
I assume roundabouts that currently have close intersection crossings are this way because the engineers/planners did their due diligence.
From you, the OP. Literally, the very first sentence you wrote:
Quote from: yand on August 28, 2021, 12:09:26 AM
A criticism I've seen regarding roundabouts is that they are dangerous to pedestrians.
in terms of traffic analysis to determine which area has the highest demand for crossings. pedestrian safety is poor in this country in general, doesn't mean they didn't do due diligence in other aspects of planning.
There is a long thread on roundabout safety. Moral of the story - roundabouts are much less universal than people wanted to believe. It is pretty similar to the opiates problem - people act on one obscure research paper as if it is ten testaments, without really understanding what they are doing.
It's fairly common in the UK to have signalised pedestrian crossings just before/after the roundabout like this...
Liverpool, England
https://maps.app.goo.gl/wAZyEWWN7hsphyKv8
Quote from: Mr Kite on August 28, 2021, 06:03:13 PM
It's fairly common in the UK to have signalised pedestrian crossings just before/after the roundabout like this...
Liverpool, England
https://maps.app.goo.gl/wAZyEWWN7hsphyKv8
One thing to notice upfront: crosswalks are close to roundabout on 30 kph side street. Crosswalk is significantly offset and signalized on a southern leg of A5058. There is room for about 6 cars between crosswalk and a circle
Compare that with
https://www.google.com/maps/@42.6888409,-73.8313851,3a,75y,40.75h,69.34t/data=!3m6!1e1!3m4!1ssUiaokswDJaDdffYVsVvYA!2e0!7i13312!8i6656
There is less than 1 car length available for exiting traffic. Pushbutton activated flashers do help, though; I believe they were added a year after construction (talking about due diligence).
Also, A5058 has a 40 km/h speed limit - and as far as I understand UK practices it is obeyed; Fuller rd (155) is 30 MPH=48 kph posted, and actual traffic is 40 MPH=65 km/h on a slow day.
A5058 is 40mph. People routinely do over 50.
Quote from: jakeroot on August 28, 2021, 12:05:11 PM
As an examples to accompany my above post, even if it is an extreme example, let's look at this roundabout in Carmel, IN (E 116 St @ Hazel Dell Pkwy).
No signals. Cool for cars, sure. But for pedestrians, this is a nightmare. At a minimum, at least four lanes of traffic have to stop to let you go, and who knows how long that will take.
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
(https://www.dronegenuity.com/wp-content/uploads/2018/03/carmel-IN-roundabout-10.jpg)
(image source: https://www.dronegenuity.com/projects/carmel-indiana-roundabout/)
For almost all of the crossings you would be only doing a 2 lane cross at one time (with the exception of the one southbound leg with a third lane. There are pedestrian refuge islands between the groups of lanes. That said this area has very little pedestrian traffic. If there were more pedestrian traffic Carmel would likely add RRFB flashing beacon lights like they've done at many other roundabouts in the area.
Quote from: 1 on August 28, 2021, 06:05:40 AM
It shouldn't be hard to cross as a pedestrian, as you're effectively crossing a series of one-way roads due to the medians. Just cross when it's clear. It may take longer, but it's not more dangerous.
I think the major difference that's been overlooked so far in this discussion is that, with roundabouts, there's no "clumping" of traffic–so "when it's clear" isn't really a thing. There's a more-or-less constant flow of traffic coming out of the roundabout. This is unlike at a stoplight intersection, where–even if a pedestrian doesn't even press the button at all–there will eventually be a red phase to work with.
Quote from: kphoger on August 31, 2021, 12:53:10 PM
Quote from: 1 on August 28, 2021, 06:05:40 AM
It shouldn't be hard to cross as a pedestrian, as you're effectively crossing a series of one-way roads due to the medians. Just cross when it's clear. It may take longer, but it's not more dangerous.
I think the major difference that's been overlooked so far in this discussion is that, with roundabouts, there's no "clumping" of traffic–so "when it's clear" isn't really a thing. There's a more-or-less constant flow of traffic coming out of the roundabout. This is unlike at a stoplight intersection, where–even if a pedestrian doesn't even press the button at all–there will eventually be a red phase to work with.
Well said. Some arterials in the Carmel and Fishers area, with lots of roundabouts, can start to feel like freeways with the constant flow of decently-fast traffic.
There is also a degree of "assertiveness" with roundabouts, since your presence is what stops traffic. At that point, you may have to activate an RRFB, grab a flag, stare at drivers, check multiple lanes, scope out a refuge island ... it's not quite as simple as hitting the ped button at a signal or just waiting for the walk sign in a timed zone (although even then, yes, you have to be cautious when crossing).
Quote from: cjw2001 on August 29, 2021, 12:24:02 AM
Quote from: jakeroot on August 28, 2021, 12:05:11 PM
As an examples to accompany my above post, even if it is an extreme example, let's look at this roundabout in Carmel, IN (E 116 St @ Hazel Dell Pkwy).
No signals. Cool for cars, sure. But for pedestrians, this is a nightmare. At a minimum, at least four lanes of traffic have to stop to let you go, and who knows how long that will take.
Crossing from one corner to the far corner? That may involve crossing as many as 11 lanes. Holy cow.
(https://www.dronegenuity.com/wp-content/uploads/2018/03/carmel-IN-roundabout-10.jpg)
(image source: https://www.dronegenuity.com/projects/carmel-indiana-roundabout/)
For almost all of the crossings you would be only doing a 2 lane cross at one time (with the exception of the one southbound leg with a third lane. There are pedestrian refuge islands between the groups of lanes. That said this area has very little pedestrian traffic. If there were more pedestrian traffic Carmel would likely add RRFB flashing beacon lights like they've done at many other roundabouts in the area.
Understood. I actually have family near the Fishers/Carmel border and am quite familiar with the intersection and surrounding neighborhood. I am aware that this area is very car-centric, but you have to wonder how much of that is the result of the infrastructure. Nothing about that roundabout screams "cross me!" Which is a shame, since Carmel and Fishers have quite a lot of good pedestrian paths.
Quote from: jakeroot on August 31, 2021, 01:18:18 PM
Understood. I actually have family near the Fishers/Carmel border and am quite familiar with the intersection and surrounding neighborhood. I am aware that this area is very car-centric, but you have to wonder how much of that is the result of the infrastructure. Nothing about that roundabout screams "cross me!" Which is a shame, since Carmel and Fishers have quite a lot of good pedestrian paths.
I'm in Westfield just barely north of Carmel - I do 6 mile walks several times a week that includes crossing at a roundabout, 2 lanes at a time. While nowhere near as busy as the Hazel Dell one referenced, I don't have any trouble finding an opportunity to cross. Much of the time the cars will come to a stop when they see me waiting at the side (sometimes I'll delay approaching until I see a gap just to avoid that).
I also cross the same street at a traditional intersection on my way back from the walk. I feel much more exposed at the normal intersection than at the roundabout since I have to worry about traffic flow in four directions to cross (main road plus traffic entering and exiting two subdivisions).
I find it interesting that the whole point of roundabouts is seen by many as being that you don't have to stop.
The main benefit of roundabouts is capacity and in appropriate locations* they perform better than traffic signals in this regard.
You will only get to go through without stopping if there's nothing already in the circle. At busy locations during busy periods, you can find yourself waiting a while. Waiting for pedestrians to cross isn't much different in principle. A lot of Europe happily sticks marked crosswalks right before the circle, where pedestrians have priority over traffic. Also, at most roundabouts, you have to slow down before entering as the geometry insists upon it (quite deliberately too), so it's not quite like putting an uncontrolled crosswalk midblock on a high speed road.
*roundabouts are not the magic solution to every scenario. The UK has many roundabouts but many more traffic signals.
Quote from: Mr Kite on September 02, 2021, 05:57:04 AM
I find it interesting that the whole point of roundabouts is seen by many as being that you don't have to stop.
The main benefit of roundabouts is capacity and in appropriate locations* they perform better than traffic signals in this regard.
You will only get to go through without stopping if there's nothing already in the circle. At busy locations during busy periods, you can find yourself waiting a while. Waiting for pedestrians to cross isn't much different in principle. A lot of Europe happily sticks marked crosswalks right before the circle, where pedestrians have priority over traffic. Also, at most roundabouts, you have to slow down before entering as the geometry insists upon it (quite deliberately too), so it's not quite like putting an uncontrolled crosswalk midblock on a high speed road.
*roundabouts are not the magic solution to every scenario. The UK has many roundabouts but many more traffic signals.
Nope. Capacity-wise roundabouts cover the upper end of stop sign controlled intersection and lower end of traffic light intersections.
Most optimistic recommendations talk about roundabouts at 30k AADT, while traffic lights can handle 40-50k.
Not necessarily. It depends on the geometry of the junction, plus how heavy the flows are in any particular direction i.e. if there's less of a N/S E/W relationship between the main flows. If every situation suggested signals were more efficient, then roundabouts wouldn't be a thing. And like I said above, the UK has plenty of roundabouts but plenty more traffic signals. Nevertheless, it's a worthwhile option to have in the locker. The other advantage I forgot to mention is that it forgoes the need for the cost of signal installation and maintenance.
Quote from: Mr Kite on September 02, 2021, 11:19:49 AM
No necessarily. It depends on the geometry of the junction, plus how heavy the flows are in any particular direction i.e. if there's less of a N/S E/W relationship between the main flows. If every situation suggested signals were more efficient, then roundabouts wouldn't be a thing. And like I said above, the UK has plenty of roundabouts but plenty more traffic signals. Nevertheless, it's a worthwhile option to have in the locker. The other advantage I forgot to mention is that it forgoes the need for the cost of signal installation and maintenance.
True, roundabouts can be more efficient - primarily for time spent at the intersection - at low traffic flows, or in primarily unidirectional traffic. Traffic lights will be better at the high-flow end of things.
Roundabout is an option - but not a
scalable option. There has to be a very good understanding that once traffic pattern changes significantly, a total rebuilt will be needed.
Quote from: cjw2001 on September 02, 2021, 12:34:20 AM
Quote from: jakeroot on August 31, 2021, 01:18:18 PM
Understood. I actually have family near the Fishers/Carmel border and am quite familiar with the intersection and surrounding neighborhood. I am aware that this area is very car-centric, but you have to wonder how much of that is the result of the infrastructure. Nothing about that roundabout screams "cross me!" Which is a shame, since Carmel and Fishers have quite a lot of good pedestrian paths.
I'm in Westfield just barely north of Carmel - I do 6 mile walks several times a week that includes crossing at a roundabout, 2 lanes at a time. While nowhere near as busy as the Hazel Dell one referenced, I don't have any trouble finding an opportunity to cross. Much of the time the cars will come to a stop when they see me waiting at the side (sometimes I'll delay approaching until I see a gap just to avoid that).
I also cross the same street at a traditional intersection on my way back from the walk. I feel much more exposed at the normal intersection than at the roundabout since I have to worry about traffic flow in four directions to cross (main road plus traffic entering and exiting two subdivisions).
I don't mean to imply that crossing at a roundabout is always an inferior experience. I think there are many roundabouts where the experience is more than safe. Pretty much every single-lane roundabout is an exceptional experience.
Where I start to question the experience is when it comes to those who maybe don't move as fast, or those who cannot see as well. For the average person, crossing at a roundabout shouldn't be difficult. If you time it right, it could even be quite fast. But for those who are not as advantageous in their ability to move at a normal pace or see as-well, I do begin to wonder if
large roundabouts (like that Hazel Dell example) become an obstacle to everyday tasks like leaving the house, since the protections of a signalized crossing are nowhere to be found.
The Hazel Dell example may be extreme, but then why was it built like that? The roundabout could certainly have been made smaller. The extra slip lanes and triple lane movements seem overkill, and removing them could have improved the pedestrian experience. Not every roundabout needs to be single-lane, but like, really, a double right turn slip lane? Those aren't even normally allowed at signalized intersections. Why here?
Carmel's original roundabouts to the north at E 126 St and E Main are great examples of pedestrian-friendly but high-capacity roundabouts. E 116 St is a busier street than either of those, but it still seems overkill.
Quote from: jakeroot on September 02, 2021, 11:28:03 AM
Quote from: cjw2001 on September 02, 2021, 12:34:20 AM
Quote from: jakeroot on August 31, 2021, 01:18:18 PM
Understood. I actually have family near the Fishers/Carmel border and am quite familiar with the intersection and surrounding neighborhood. I am aware that this area is very car-centric, but you have to wonder how much of that is the result of the infrastructure. Nothing about that roundabout screams "cross me!" Which is a shame, since Carmel and Fishers have quite a lot of good pedestrian paths.
I'm in Westfield just barely north of Carmel - I do 6 mile walks several times a week that includes crossing at a roundabout, 2 lanes at a time. While nowhere near as busy as the Hazel Dell one referenced, I don't have any trouble finding an opportunity to cross. Much of the time the cars will come to a stop when they see me waiting at the side (sometimes I'll delay approaching until I see a gap just to avoid that).
I also cross the same street at a traditional intersection on my way back from the walk. I feel much more exposed at the normal intersection than at the roundabout since I have to worry about traffic flow in four directions to cross (main road plus traffic entering and exiting two subdivisions).
I don't mean to imply that crossing at a roundabout is always an inferior experience. I think there are many roundabouts where the experience is more than safe. Pretty much every single-lane roundabout is an exceptional experience.
Where I start to question the experience is when it comes to those who maybe don't move as fast, or those who cannot see as well. For the average person, crossing at a roundabout shouldn't be difficult. If you time it right, it could even be quite fast. But for those who are not as advantageous in their ability to move at a normal pace or see as-well, I do begin to wonder if large roundabouts (like that Hazel Dell example) become an obstacle to everyday tasks like leaving the house, since the protections of a signalized crossing are nowhere to be found.
The Hazel Dell example may be extreme, but then why was it built like that? The roundabout could certainly have been made smaller. The extra slip lanes and triple lane movements seem overkill, and removing them could have improved the pedestrian experience. Not every roundabout needs to be single-lane, but like, really, a double right turn slip lane? Those aren't even normally allowed at signalized intersections. Why here?
Carmel's original roundabouts to the north at E 126 St and E Main are great examples of pedestrian-friendly but high-capacity roundabouts. E 116 St is a busier street than either of those, but it still seems overkill.
As long as there are safety islands between lane groups, multiple groups would be mostly psychological issue. That doesn't change overall trip length, nor increases number of vehicles to deal with.
My main issue with roundabouts I crossed myself both walking and driving, is ability of drivers already in roundabout to see pedestrian in time, being able to stop in time, and doing so without blocking the flow - especially during higher traffic periods.
Quote from: kalvado on September 02, 2021, 11:41:53 AM
As long as there are safety islands between lane groups, multiple groups would be mostly psychological issue. That doesn't change overall trip length, nor increases number of vehicles to deal with.
My main issue with roundabouts I crossed myself both walking and driving, is ability of drivers already in roundabout to see pedestrian in time, being able to stop in time, and doing so without blocking the flow - especially during higher traffic periods.
Issue is number of lanes combined with number of lane groups. All but one group at the Hazel Dell/116 roundabout is two lanes. Can be a problem for pedestrians due to multiple lanes needing to stop for pedestrians, and (a) pedestrians do not check that both lanes have stopped, and (b) the stopped car creates a blind spot for the other car, and the other car fails to see the pedestrian in time. Double-lane entries are
fine but should only be used as necessary. Slip lanes don't need two lanes apart from very rare situations.
Drivers exiting a roundabout are usually not checking for anyone, so yes it is also a problem, but drivers entering roundabout seem focused (rightly so) on cars, failing to consider the potential for other traffic like peds or bikes.
I thought some more about the Hazel Dell and 116th roundabout from a pedestrian standpoint, contemplating crossing at the old stoplight vs the new roundabout setup.
Even with the stoplight the previous setup would be quite dangerous with having to monitor the high volume of turning traffic from multiple directions while having to cross 5 lanes with no refuge areas. https://www.google.com/maps/@39.9567248,-86.0736785,3a,75y,254.6h,84.29t/data=!3m6!1e1!3m4!1sSQxalH2EwOb0sDrml8CnmQ!2e0!7i3328!8i1664
With the new setup you only have to monitor traffic from a single direction and each crossing is much shorter distance. As a pedestrian I'd much rather deal with the new setup. Not saying it couldn't be further improved, just that it is far better than what was there before.
Studies have, in fact, shown that pedestrians with impaired do have issues with roundabouts due to the sound of circulating traffic, and those problems are much worse at multi-lane roundabouts (in addition, traffic tends to move faster in those, due to straighter entry/exit lanes). As such, the PROWAG ADA standards (which FHWA has been looking to adopt) require some form of signalization, such as a HAWK or regular traffic light at multi-lane roundabouts.
Quote from: cjw2001 on September 02, 2021, 12:57:09 PM
Even with the stoplight the previous setup would be quite dangerous with having to monitor the high volume of turning traffic from multiple directions while having to cross 5 lanes with no refuge areas.
But, back then, peds had a stoplight-controlled crossing phase.
Quote from: kphoger on September 02, 2021, 01:08:40 PM
Quote from: cjw2001 on September 02, 2021, 12:57:09 PM
Even with the stoplight the previous setup would be quite dangerous with having to monitor the high volume of turning traffic from multiple directions while having to cross 5 lanes with no refuge areas.
But, back then, peds had a stoplight-controlled crossing phase.
Indeed. And it should be noted that, no matter how large an intersection, the same three crossing movements are apparent: both right turns (RTOR and right on green), plus left turns. Theoretically, all can be modified to eliminate movements while the walk sign is on, as is often done in the Netherlands.
Quote from: vdeane on September 02, 2021, 12:59:18 PM
Studies have, in fact, shown that pedestrians with impaired do have issues with roundabouts due to the sound of circulating traffic, and those problems are much worse at multi-lane roundabouts (in addition, traffic tends to move faster in those, due to straighter entry/exit lanes). As such, the PROWAG ADA standards (which FHWA has been looking to adopt) require some form of signalization, such as a HAWK or regular traffic light at multi-lane roundabouts.
I was not familiar with those standards until now. I will be reading more about it. Thank you.
Quote from: jakeroot on September 02, 2021, 01:32:33 PM
Quote from: vdeane on September 02, 2021, 12:59:18 PM
Studies have, in fact, shown that pedestrians with impaired do have issues with roundabouts due to the sound of circulating traffic, and those problems are much worse at multi-lane roundabouts (in addition, traffic tends to move faster in those, due to straighter entry/exit lanes). As such, the PROWAG ADA standards (which FHWA has been looking to adopt) require some form of signalization, such as a HAWK or regular traffic light at multi-lane roundabouts.
I was not familiar with those standards until now. I will be reading more about it. Thank you.
Ooh, yes, interesting...
https://www.adainfo.org/sites/default/files/1.4-Public-Rights-of-Way-2-slides-per-page.pdf (see page 46)
Quote from: kphoger on September 02, 2021, 01:08:40 PM
Quote from: cjw2001 on September 02, 2021, 12:57:09 PM
Even with the stoplight the previous setup would be quite dangerous with having to monitor the high volume of turning traffic from multiple directions while having to cross 5 lanes with no refuge areas.
But, back then, peds had a stoplight-controlled crossing phase.
Understood, but there was left and right turn traffic that conflicted with the walk light. I'd still take the roundabout over the long crossing distance with a light.
Quote from: cjw2001 on September 02, 2021, 05:55:45 PM
Quote from: kphoger on September 02, 2021, 01:08:40 PM
Quote from: cjw2001 on September 02, 2021, 12:57:09 PM
Even with the stoplight the previous setup would be quite dangerous with having to monitor the high volume of turning traffic from multiple directions while having to cross 5 lanes with no refuge areas.
But, back then, peds had a stoplight-controlled crossing phase.
Understood, but there was left and right turn traffic that conflicted with the walk light. I'd still take the roundabout over the long crossing distance with a light.
True, but those issues can be mitigated through other measures as necessary, including improved signalization, leading pedestrian intervals, pedestrian lockout (red arrows during walk phase); plus, there's still all of the additional ADA 'equipment' that you don't have at roundabouts, such as actual walk/don't walk signals and sounds ('walk signal is on to cross...').
I also ran some distance measurements on the old signal vs the new one at Hazel Dell/E 116. The old signal took 233 feet to cross from one corner to the opposite corner. The new roundabout takes about 330 to 400+ feet to cover the same distance. Because crosswalks at roundabouts are offset, there is some level of back-tracking required. Not all of that distance are you exposed to traffic, to be fair, but the same is true at signals where the approach lanes have red lights and do not conflict with the walk sign (apart from right-on-red).
Quote from: kalvado on September 02, 2021, 11:27:06 AM
Quote from: Mr Kite on September 02, 2021, 11:19:49 AM
No necessarily. It depends on the geometry of the junction, plus how heavy the flows are in any particular direction i.e. if there's less of a N/S E/W relationship between the main flows. If every situation suggested signals were more efficient, then roundabouts wouldn't be a thing. And like I said above, the UK has plenty of roundabouts but plenty more traffic signals. Nevertheless, it's a worthwhile option to have in the locker. The other advantage I forgot to mention is that it forgoes the need for the cost of signal installation and maintenance.
True, roundabouts can be more efficient - primarily for time spent at the intersection - at low traffic flows, or in primarily unidirectional traffic. Traffic lights will be better at the high-flow end of things.
Roundabout is an option - but not a scalable option. There has to be a very good understanding that once traffic pattern changes significantly, a total rebuilt will be needed.
as an adjacent topic, I feel like the poor performance of busy roundabouts in simulations and real life are in large part due to improper technique rather than inherent to roundabouts. People and AI treat roundabouts as right turns rather than freeway merges. If drivers just leave a little bit of space while waiting, they will have room to accelerate and easily take small gaps in traffic, and it will result in much shorter wait times.
Quote from: jakeroot on September 03, 2021, 12:23:30 PM
True, but those issues can be mitigated through other measures as necessary, including improved signalization, leading pedestrian intervals, pedestrian lockout (red arrows during walk phase); plus, there's still all of the additional ADA 'equipment' that you don't have at roundabouts, such as actual walk/don't walk signals and sounds ('walk signal is on to cross...').
I still think comparing apples to apples (what was/is actually there) is valid vs what could have been and might be. And what is there now is better than what was there.
I'm still haunted by the memory of seeing a trash truck driver cleaning up a spill in the road on 116th not far from that intersection and driving by thinking "that's not safe" only to see on the news later that night he was killed minutes later by a car that didn't see him. I just don't trust drivers to see pedestrians and would rather have a shorter distance to cross where I only have to watch for a small subset of the total intersection traffic that is moving in only one direction.