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Wanted: Example of Safer 2-lane Slip Road Crossing [Limited Scope]

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Wanted: Example of Safer 2-lane Slip Road Crossing [Limited Scope]

Old 10-03-22, 10:05 AM
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flangehead
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Wanted: Example of Safer 2-lane Slip Road Crossing [Limited Scope]

[OK, I'll try "limited scope" again; may be a more appropriate thread. The context is that this project is going to happen and the best I can hope to achieve is to make the best of it. Whether this kind of road should be built in the first place isn't relevant. I'd like to limit the scope to good and bad examples of infrastructure for this situation.]

Design has begun on adding another turn-only lane to the intersection of a major arterial and an interstate frontage road in my area. This intersection provides a key crossing of the interstate linking two major regional MUP.


Existing intersection. MUP connection in yellow. They will add another right-turn-only lane.

I'm looking for examples of "safer" solutions that could be implemented for this situation. My first guess is that a refuge island will be needed, but fundamentally I'm looking for examples of how this has been done well in other locations. And frankly, if you have an example where an attempt was done to protect vulnerable road users but has led to same/more injuries, that could help me influence the designers also.

Thank you.
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Old 10-03-22, 10:32 AM
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relocate each ped crossing by put all current ped crossings 500' prior to each light, install ped sensor detection devices, manual ped override crossing mechanisms, add in a cursory for slow speed rumble strips, reflective painted lines & high vis signs for addressing vehicle's approaching with good viewable signage.
Or erect an overpass for the ped's crossing.
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Old 10-03-22, 11:46 AM
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The perfect solution of course would be a flyover bridge for through bike traffic.

Failing that, the most efficient and safe design for cyclists riding typical commuting distances is to provide a through bicycle lane to the left of the right turn lanes.

If people do or do not feel comfortable using that depends on both the user and the traffic flow - there are places where I'd do that at some hours, but not others.

If you're going to keep bikes on the dangerously improper righthand side of the turning lane, then you really have to go through the whole expansive exercise of prohibiting right on red and creating a dedicated signal phase. Doing that means everyone loses. Ideally you make the signal phase on a timer or automatic, if you're going to be using a pedestrian "beg button" as your solution for bike crossing it had better be the only such anti-cyclist intersection in at least a mile of otherwise conflict-free through path.

And for heaven's sake if there has to be a beg button, put the beg button pylon on the right side of the path, not the left! It's absurd how often they get even that wrong.

Alternately you can displace the MUP crossing far enough from the intersection to have its own perpendicular controlled crossing. If you're going to do that, you really should use a motion activated automatic traffic light, not a beg button. And it absolutely has to be an actual traffic light that shows a proper and lasting red to the road - none of this legally meaningless white flasher nonsense, nor lights that go blinking red to allow traffic to resume, as flashing red lights are a recipe for killing the second path user who's following a few seconds behind the first.

So basically build the bridge. If you can't build the bridge build the bike lane to the left of the right turn lanes, and get the pedestrian crossing right so that those who aren't comfortable in that correctly routed bike lane can take the pedestrian option instead.

Last edited by UniChris; 10-03-22 at 11:54 AM.
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Old 10-04-22, 08:35 AM
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How do the Dutch and the Danish do it? I googled and the first thing I found was "No unsignalized right turn lanes for cars,..."

Then that reminded me of a challenging intersection in Toronto that had several changes in the past year. It was the east bound end of the Bloor Street viaduct where fast moving cars on the right lane go to the north bound ramp of the DVP and cyclists on the bike lane have to cross over from the right side to the left side of that car lane.

The latest configuration has three phase traffic lights cycling from bicycle, pedestrian and cars with each having its own green and red lights.

That double-right turn in the OP's photo should have a right turn traffic light triggered by detectors on the bike lane. And move the solid stop line backwards further from the intersection. I've seen this in several cities and it gives pedestrians a head start crossing intersections before cars do.

Last edited by Daniel4; 10-04-22 at 08:56 AM.
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Old 10-04-22, 09:17 AM
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Originally Posted by Daniel4 View Post
...Then that reminded me of a challenging intersection in Toronto that had several changes in the past year. It was the east bound end of the Bloor Street viaduct where fast moving cars on the right lane go to the north bound ramp of the DVP and cyclists on the bike lane have to cross over from the right side to the left side of that car lane.

The latest configuration has three phase traffic lights cycling from bicycle, pedestrian and cars with each having its own green and red lights....
Is Google Map/Streetview current? Or did I even get the right place?


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Old 10-04-22, 09:36 AM
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Originally Posted by flangehead View Post
Is Google Map/Streetview current? Or did I even get the right place?


Yes. That's the right place.
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Old 10-04-22, 02:39 PM
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What does "[Limited Scope]" in the thread title mean?

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Old 10-04-22, 02:52 PM
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Maybe a version of this could be executed??

Protected Island with 2 traffic buttons in the middle and on the far side of the road. (Once it's green for the cyclists - the next intersection upstream is green longer the next time ... to allow vehicle traffic to "catch back up".
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Old 10-04-22, 05:38 PM
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Originally Posted by flangehead View Post
Is Google Map/Streetview current? Or did I even get the right place?


Here's a picture I just took today. Each mode has two traffic lights to make sure cars and cyclists have no excuses not to see them. Pedestrians have their regular one signal at the crosswalk right on the on-ramp.
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Old 10-07-22, 07:56 AM
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Originally Posted by masonv45 View Post
Maybe a version of this could be executed?? (Shelby Farms Greenline at Germantown Parkway)... Protected Island with 2 traffic buttons in the middle and on the far side of the road. (Once it's green for the cyclists - the next intersection upstream is green longer the next time ... to allow vehicle traffic to "catch back up".
OK, so not a HAWK, Do you (and others) find it works?


Current Google map.
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Old 10-07-22, 08:08 AM
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I've used it many - many times. It works great! Once you hit the button, the traffic nearest you stops while you cross to the center island.
Once there, you hit the button to cross the far lane. Traffic stops on the far lane and then you cross.

The wait time is about 2-3 minutes for each crossing (if you wait for the light) - so a total of about 4 - 6 minutes to cross. If traffic is light, you can cross the lane(s) without waiting for the light.

Little history - that crossing used to be a railroad crossing (not used for probably 30 years).
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Old 10-07-22, 09:41 AM
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Originally Posted by masonv45 View Post
The wait time is about 2-3 minutes for each crossing (if you wait for the light) - so a total of about 4 - 6 minutes to cross. If traffic is light, you can cross the lane(s) without waiting for the light.
4-6 minutes to cross one road is a perfect example of discouraging biking by making it impractical. No other user has to wait that long to go through an intersection.

120-150 seconds is at the aggravating upper end for a complicated intersection.

The people who demand bike specific traffic lights rather than proper positioning to the left of right turn lanes forget that it means cyclists have even less of the time when they can go through that drivers do - it only ends up compounding all the ways that design says "we'll let you bike, but we're not going to encourage it"

The proper solution is to keep it legal for cyclists to go through the intersection in a properly routed through lane exactly as a driver would, but also give the option to pull over and use the pedestrian crossing button if that particular cyclist feels intimidated by the traffic flow at that hour.

The key difference is the option vs the requirement to wait extra time for a signal that most of the cyclists using the intersection won't need much of the time.

Last edited by UniChris; 10-07-22 at 09:49 AM.
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Old 10-07-22, 11:08 AM
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Originally Posted by UniChris View Post
4-6 minutes to cross one road is a perfect example of discouraging biking by making it impractical. No other user has to wait that long to go through an intersection.


120-150 seconds is at the aggravating upper end for a complicated intersection.


The people who demand bike specific traffic lights rather than proper positioning to the left of right turn lanes forget that it means cyclists have even less of the time when they can go through that drivers do - it only ends up compounding all the ways that design says "we'll let you bike, but we're not going to encourage it"


The proper solution is to keep it legal for cyclists to go through the intersection in a properly routed through lane exactly as a driver would, but also give the option to pull over and use the pedestrian crossing button if that particular cyclist feels intimidated by the traffic flow at that hour.


The key difference is the option vs the requirement to wait extra time for a signal that most of the cyclists using the intersection won't need much of the time.

I think you misunderstand the purpose of the crossing at the intersection I specified. It is a MUP crossing a 7 lane "extremely busy" (60,000+ vehicles a day) road where before - there were no lights and no center median. I would not want to cross this road without a light in my fastest running shoes! The MUP gets about 200,000 visitors a year.


This is what can happen when
we'll let you bike, but we're not going to encourage it


https://www.commercialappeal.com/sto...ms/6309518002/
After crash claimed cyclist's life, city pushes for safety upgrades near Shelby Farms

This intersection has cross walk signals, signage, road markings, and an unprotected center median and no curbs


Intersection: https://www.google.com/maps/@35.1349...7i16384!8i8192

Shelby Farms is one of the largest urban parks in the US and the world, at a size of 4,500 acres and covers more than five times the area of Central Park in New York City with 843 acres. Over 3 million visitors use the park each year.
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Old 10-07-22, 11:21 AM
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Originally Posted by masonv45 View Post
I think you misunderstand the purpose of the crossing at the intersection I specified. It is a MUP crossing a 7 lane "extremely busy" (60,000+ vehicles a day) road where before - there were no lights and no center median. I would not want to cross this road without a light in my fastest running shoes! The MUP gets about 200,000 visitors a year.
That's still not a justification for it to take 4-6 minutes. If they were actually serious about bike transit, it would take no more than 2 minutes to cross, just like it would if one were on a road having a similar intersection.

But they're not serious - MUP's are managed as "recreation" not "transit" - and abusively inequitable design like this only keeps them that way.

But that's kind of beside the point, because your post is off topic for the thread - the thread is about supporting through bikes in the presence of right tuns, but your example does not address the thread topic at all - all you've shown is an example of unworkable design in a different situation.
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Old 10-07-22, 12:41 PM
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I'm not sure my posts are completely off topic... hmmm ... maybe. I was just trying to present an option that may (or as you put it) "an unworkable" option that could be revised for the intersection. Sorry to muddy up the waters.
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Old 10-07-22, 01:30 PM
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Originally Posted by GAtkins View Post
What does "[Limited Scope]" in the thread title mean?

Glenn
From time to time A&S threads stray from the original purpose, which can be entertaining, useful, and/or frustrating.

At times I have a very specific request and when I do I am trying to designate it as a limited scope.

Staying to the limited scope is of course the decision of individual posters.
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Old 10-07-22, 01:32 PM
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Originally Posted by flangehead View Post
From time to time A&S threads stray from the original purpose, which can be entertaining, useful, and/or frustrating.

At times I have a very specific request and when I do I am trying to designate it as a limited scope.

Staying to the limited scope is of course the decision of individual posters.
Gotcha. Thanks for the explanation.

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Old 10-07-22, 01:33 PM
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Originally Posted by masonv45 View Post
I'm not sure my posts are completely off topic... hmmm ... maybe. I was just trying to present an option that may (or as you put it) "an unworkable" option that could be revised for the intersection. Sorry to muddy up the waters.
Thank you for providing a real-life situation and solution.
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Old 10-07-22, 03:08 PM
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I don't have the answer. Or any answer, really. I'd be skeptical of anyone who claims with absolute certainty that they do. The challenge to your question lies in that there are so few examples in North American infrastructure to pull from. But whatever is implemented should slow the cars & make it abundantly clear that the car is entering people space.

It'd be nice if all non-car infrastructure was at the same level, smooth, flat, continuous, etc...this would force cars to rise to crossing level. Forcing drivers to slow down, reducing the risk to those outside the vehicle in the event of collision or the severity of any collision.

Raised crosswalks are hardly unprecedented. Maybe a speed bump or two before the approach for the same reason could help. Then visually narrow the appearance of the lanes with painted lines or adjacent brick work if physically narrowing the lanes is not an option. These issues could be approached through an ADA compliance lens. Shorter crossing distances in addition to being easier for the vulnerable to cross, also reduce driver interruption through reduced reduced pedestrian crossing time. (Higher LOS)

Of course pedestrian prioritized leading signals would be the bees knees. We have them at a number of intersections in North Seattle. They work.

On a related note, is there such a thing as an approved "pedestrian in waiting" sensor on the pedestrian path in the same vein as the cars in the queue sensor in the car lane? Beg buttons are lame & IME only sometimes work. The Netherlands uses radar to automatically detect pedals/cyclists. Could this or a similar system be used here in some fashion? Maybe signalize the slip lane independent of other flows minimizing delay from any user to any other user?

It also wouldn't hurt to place signals on the near side of the crossing so that for drivers to see the light they must stop before the crossing rather than park in the crossing while staring into the distance waiting for the signal to change...Maybe an earlier signal indication light upstream so that a driver has indication of the slip lane signals status ahead of time.

Stopping the cars further back so that any vulnerable users are placed squarely in the slip lane drivers field of view in front of the windshield seems like a good idea.

Signals that cycle on actual need favoring vulnerable road users doesn't seem like a bad idea either. There is little sense stopping anybody from any flow unnecessarily.

Failing slowing the cars so that drivers can adequately make informed decisions in the traffic environment: Can any implemented refuge island have a substantial decorative planter, or other life saving barrier installed to protect & shield the vulnerable user & guide an out of control vehicle to a less perpendicular path to other road users? Is there even a president for this? It would suck for somebody to get T-boned when it could be a glancing blow instead. A substantial planter to guide vehicles to a less harmful path would also have a benefit of being one more visual cue to impose on drivers perception of safety nudging them towards a desired behavior.

I'd like to end all turn on red & fill in the slip lane with a rain garden (environmental impact lens) & square up the corner in as much as is practical. I know that'll ain't no way never gonna happen. But bleeding off 5-10mph before hand would save lots of injury & liability to all parties. Crashed car drivers included.

I don't know what the design speed of this project is. But I'll ask: What is the desired speed? What can be implemented to convince a driver to self-select that speed intuitively?

I'm just spit-ballin'
I don't know any silver bullet solution. But aren't there references in the current design manuals that allow for discretion based on local conditions or requirements? There must be, right? I know relying on driver compliance is a fools errand. The pessimist in me says to count on driver non-compliance. I also know engineers are given discretion neigh the responsibility to design a product that meets the customers needs. That's one of the responsibilities of being any kind of engineer in any field.

IMO: The design needs to primarily minimize injury to the most vulnerable. Maybe it would be a good idea to get a person in authority to tell you that cyclists & pedestrians are a significant consideration if not the primary consideration for the desired design outcome rather than something to merely be accommodated as an afterthought per the (evidently) usual approach. To that end, can you walk the location with the Mayor or influential Council member? Traffic engineers think in terms of cars & physics problems. Mayors & council members think in terms of human values. I would hope that since they're the ones paying for it, that dialogue would likely buy some much needed latitude impressing their (your) values in any proposals.

To put those values in engineering terms: Given the desired pedestrian ped/cyclist perception of safety, what is the anticipated adoption rate? How many new cyclists or pedestrians can be induced into using this new infrastructure? What is the LOS this project will afford to them? Are these questions being prominently addressed & taken into consideration with equal priority to that of automobile through put?

I am typing this in a genuine attempt to be helpful; Maybe a new idea or approach to a problem can be shook loose to be evaluated & acted on or discarded according to its merits.

Base2

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