2012 MATC Fall Lecture Series: Eugene Russell
Larissa Sazama
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11/08/2017
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2012 MATC Fall Lecture Series
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- [00:00:00.808]Welcome everyone to the MATC Seminar series.
- [00:00:03.959]Today we're gonna hear about roundabouts
- [00:00:05.352]from Dr. Gene Russell,
- [00:00:07.935]Professor Emeritus at Kansas State University.
- [00:00:11.087]I was gonna list all his awards,
- [00:00:14.044]but I don't think we have the time to do that,
- [00:00:16.595]other than he's internationally famous
- [00:00:19.070]and we're very fortunate to have him talking with us today.
- [00:00:22.322]So with that, I'm gonna pass you off, Gene.
- [00:00:24.699]I'm looking forward to your talk.
- [00:00:25.993]Thanks.
- [00:00:26.826]Thank you, Larry.
- [00:00:28.182]And thank you for those kind words.
- [00:00:33.854]Yes, and Larry told me to keep this fairly basic
- [00:00:40.829]and so that's why I called it Roundabouts 101.
- [00:00:46.239]But I put in the "and beyond."
- [00:00:47.981]I will include some other things, but if you
- [00:00:53.131]have a lot of experience and education on roundabouts,
- [00:00:57.511]you might not learn anything new except
- [00:01:00.550]when I get into the research that we've been doing
- [00:01:04.879]over the years.
- [00:01:06.805]Okay, today's presentation is going to be why roundabouts,
- [00:01:12.279]some intersection safety statistics,
- [00:01:15.632]circle differences,
- [00:01:19.152]safety examples,
- [00:01:21.734]latest roundabout crash statistics,
- [00:01:25.045]pedestrian and bicycle safety,
- [00:01:28.078]visually impaired concerns and PROWAG.
- [00:01:32.181]I'll explain what that means.
- [00:01:35.434]A lot of you probably don't
- [00:01:38.892]know what PROWAG is
- [00:01:40.422]but you're gonna hear a lot about it in the future.
- [00:01:44.973]Benefits other than safety and some history,
- [00:01:47.374]if time permits.
- [00:01:48.532]I love history.
- [00:01:49.365]I might have been a historian,
- [00:01:52.625]but the thing that held me back
- [00:01:56.077]was trying to figure out how I would make a living
- [00:01:58.617]if I got my degrees in history.
- [00:02:02.330]Engineering seemed more appreciative.
- [00:02:12.314]Okay, to the objective:
- [00:02:17.099]to be honest, to give you a reason to love roundabouts.
- [00:02:22.804]I'll tell you up front I am biased,
- [00:02:29.396]and so with that disclosure ...
- [00:02:31.421]They say we're supposed to disclose our biases.
- [00:02:34.702]Some of this information is a little old
- [00:02:38.077]but I don't think it's changed that much.
- [00:02:40.117]This is 2002.
- [00:02:41.822]I like to get across the intersection problem
- [00:02:45.306]that we do have.
- [00:02:47.571]I think this is 2002 data.
- [00:02:49.644]I will update this shortly,
- [00:02:52.582]but we have one intersection-related fatality every hour,
- [00:02:56.392]two intersection-related injury crashes every minute,
- [00:03:00.433]five intersection-related crashes every minute.
- [00:03:03.978]That's appalling really, but that's the way it is.
- [00:03:08.520]Pedestrians: one pedestrian killed every two hours;
- [00:03:12.010]eight pedestrians injured every hour;
- [00:03:14.146]thirteen pedestrians killed each day.
- [00:03:17.546]And again, this at mostly at traditional intersections.
- [00:03:25.114]You can see here, in relation to intersections,
- [00:03:29.656]sometimes referred to worldwide more as junctions,
- [00:03:36.798]9,316 persons killed
- [00:03:40.264]at roadway junctions,
- [00:03:42.656]7,717 at the intersections,
- [00:03:47.161]1,599 related.
- [00:03:50.056]You probably all know what we mean by intersection related.
- [00:03:53.128]If you have an intersection that backs up traffic
- [00:03:55.784]to mid-block, and then there's a crash mid-block,
- [00:04:00.672]it's still intersection related
- [00:04:02.277]because even though it was mid-block,
- [00:04:04.680]it was because the intersection backed it up.
- [00:04:07.529]So that's what traffic related is.
- [00:04:11.040]So again you can see in 2002,
- [00:04:13.373]we had 42,850 killed on our highways.
- [00:04:18.217]Now fortunately, it's really great that this has come down,
- [00:04:22.246]but still in injured, almost a million and a half injured
- [00:04:28.888]at intersections and intersection related,
- [00:04:32.081]almost three million total from highway crashes.
- [00:04:36.471]Now update that a little bit.
- [00:04:39.184]I know most everybody likes to see how that's changed.
- [00:04:41.968]And I said the good news is that we're coming down.
- [00:04:45.888]We're coming down both in fatalities and injuries.
- [00:04:50.016]You can see this is the great news.
- [00:04:52.241]But still, in 2010 we had 32,885 fatalities
- [00:04:58.401]where we had 43,005
- [00:05:04.054]back in 2002 according to these latest statistics
- [00:05:07.490]that you can get online.
- [00:05:10.030]Even 32,885 is
- [00:05:15.671]is a lot of people killed on our highways
- [00:05:17.398]and we've got to keep working to improve that.
- [00:05:22.144]2010, two thousand 239,000 injured
- [00:05:28.612]versus two thousand 926,000 in 2002
- [00:05:35.767]and the rates are greatly improved.
- [00:05:37.480]But let's look at intersections.
- [00:05:38.832]Here again, roundabout is an intersection.
- [00:05:40.759]That's one thing some people forget
- [00:05:43.408]that roundabout is an intersection.
- [00:05:45.865]We shouldn't forget that.
- [00:05:47.713]But here say it
- [00:05:52.333]has it broken down by traffic signal, stop sign, and other.
- [00:05:56.338]I don't know, other doesn't include a lot of roundabout.
- [00:06:00.251]I've been dealing with roundabout research
- [00:06:04.105]and studying roundabouts since about 1997.
- [00:06:09.386]And I haven't heard of one pedestrian killed
- [00:06:11.234]at a roundabout.
- [00:06:12.234]There have been a few people killed at roundabouts.
- [00:06:16.144]You can't prevent
- [00:06:20.792]some crazy driver from trying to drive 80 miles an hour
- [00:06:25.633]through a roundabout ending up killed in the center.
- [00:06:31.001]But then, most of these crashes,
- [00:06:36.964]and injuries,
- [00:06:38.998]and fatalities we have at intersections
- [00:06:40.904]are at traffic signals,
- [00:06:43.570]stop signs, and then unsignal.
- [00:06:45.384]Let's look at the traffic signal and stop sign.
- [00:06:49.133]In 2010, 4,471
- [00:06:54.719]total crashes at signals,
- [00:06:57.286]2,822 at stop signs.
- [00:07:00.076]The injury crashes, 819,000 at traffic signals,
- [00:07:04.249]205,000 at stop signs.
- [00:07:06.687]So let's not look at the total.
- [00:07:09.267]The percent has stayed pretty much the same,
- [00:07:15.555]around 23% to 25% for 2010.
- [00:07:20.164]Percent of vehicles is a little different
- [00:07:22.372]than percent of people.
- [00:07:26.214]But 26.6%
- [00:07:29.888]of the people that
- [00:07:34.329]killed on our highways
- [00:07:37.097]are at the traffic signal, 6.9% at stop signs, okay.
- [00:07:43.410]Pedestrians, let's just look at the bottom line here.
- [00:07:46.169]At intersections, 900 pedestrians killed,
- [00:07:49.338]32,000 injured.
- [00:07:52.810]Pedalcyclists, 205
- [00:07:57.547]killed at intersections,
- [00:07:59.527]34,000 injured.
- [00:08:03.272]And again, these are about 99% at traditional intersections.
- [00:08:10.008]Red light running, and I couldn't find
- [00:08:12.405]the 2010 statistics on this.
- [00:08:16.665]But in 2001, I know we were running
- [00:08:19.872]over 1000 deaths a year just from red light running
- [00:08:24.858]and 1500 injuries.
- [00:08:26.451]I know it's down to around 800 in 2010.
- [00:08:31.747]And cities are putting up red light cameras
- [00:08:34.009]that catch red light runners, and that's very controversial
- [00:08:37.178]because people don't like being caught with a camera.
- [00:08:41.297]Let's take a quick look ...
- [00:08:45.145]Watch the lane to the right.
- [00:08:50.592]Look. I don't know how that guy got through.
- [00:08:53.177]But I had some other videos.
- [00:08:58.657]You can go to the YouTube.
- [00:09:01.322]They weren't playing very well
- [00:09:06.476]for this presentation.
- [00:09:08.418]But you can just put in "red light running crashes"
- [00:09:11.227]and you'll bring up some really spectacular stuff
- [00:09:13.362]on YouTube.
- [00:09:16.122]And these were a couple that Clarissa put in the URLs for
- [00:09:22.840]but you can just Google "red light running crashes,"
- [00:09:26.119]and get a lot of this stuff.
- [00:09:27.832]But what's my point?
- [00:09:28.978]What's my point?
- [00:09:30.097]The point is traffic signals and stop signs
- [00:09:33.729]are not as safe as the public thinks.
- [00:09:37.054]You know, you can hear, when a roundabout is proposed,
- [00:09:40.000]people say, "Oh, we don't want that crazy thing."
- [00:09:43.824]You hear comments that it's dangerous,
- [00:09:45.826]it'll kill people.
- [00:09:48.042]"Put in a traffic signal so we'll be safe."
- [00:09:51.522]It doesn't work that way.
- [00:09:52.890]And if you think about those statistics I just showed,
- [00:09:56.842]that's pretty spectacular proof
- [00:10:06.614]that signals and stop signs are not all that safe.
- [00:10:12.218]Okay, what is it not?
- [00:10:13.545]It is not the Arc de Triomphe that is in Paris.
- [00:10:17.704]I think I scanned that off a postcard.
- [00:10:20.570]This is the traffic down there.
- [00:10:22.145]I took that myself.
- [00:10:23.947]I was at a conference in Paris and I walked up
- [00:10:26.914]about 200 stairs to get to the top with a bad knee.
- [00:10:32.930]And what I didn't realize
- [00:10:34.498]I was up there almost dreading walking back down
- [00:10:37.593]because if you've ever had a bad knee,
- [00:10:40.729]you know that generally it hurts more going downstairs
- [00:10:45.121]than upstairs.
- [00:10:46.922]And the wall behind me opened and I realized
- [00:10:49.691]they had a elevator. (laughs)
- [00:10:54.209]Anyway, I wish I'd known that going up.
- [00:10:56.673]But I got to tell you this, it amused me.
- [00:11:01.194]A lot of people up there started running
- [00:11:03.147]toward the elevator.
- [00:11:04.330]And the elevator operator says, "No, no, no.
- [00:11:08.051]"This is for old people and sick people."
- [00:11:11.473]And she points at me and she says, "You're okay."
- [00:11:17.289]I got a real kick out of that.
- [00:11:20.385]Here's another one.
- [00:11:22.089]A lot of people confuse modern roundabouts
- [00:11:26.024]with these old, big old traffic circles.
- [00:11:28.161]We have a lot of them in the east
- [00:11:29.644]in Massachusetts and New Jersey.
- [00:11:31.956]In fact, they didn't work.
- [00:11:33.212]They're dangerous. They're confusing.
- [00:11:34.507]They're taking them out.
- [00:11:35.898]You hear a lot, "Well how can you promote roundabouts?
- [00:11:39.147]"They don't work in New Jersey.
- [00:11:41.355]"They don't work in Massachusetts.
- [00:11:42.978]"They're tearing them out."
- [00:11:44.532]Well, they're talking about these little traffic circles
- [00:11:46.867]and I'll agree.
- [00:11:47.978]They were high speed, a lot of weaving,
- [00:11:51.058]confusing, and high risk.
- [00:11:54.799]You can see the entries here were generally tangential
- [00:11:57.860]and high speed.
- [00:11:59.748]Look at the crossing, look at the weaving
- [00:12:01.299]and crossing traffic in here.
- [00:12:03.323]It's almost a free-for-all.
- [00:12:06.164](video playing in background)
- [00:12:20.353]When traffic gets heavy, it gets more confusing.
- [00:12:22.707]Watch that truck come right out and cut across the traffic.
- [00:12:31.223]And almost block ...
- [00:12:32.583]You can see, the heavier traffic gets
- [00:12:35.110]the more confusing these are.
- [00:12:37.242]Again, the modern roundabout is different
- [00:12:39.369]than these old traffic circles.
- [00:12:47.129]That bicycle is pretty brave to ride through there.
- [00:12:52.354]Okay, I think that gets the point.
- [00:12:54.677]What I was going to show.
- [00:12:56.861]This is a camcorder that shows live operation
- [00:13:02.801]on a very complex,
- [00:13:06.724]looks like well designed roundabout in Halifax.
- [00:13:11.454]It's got sections of one lane, two lane,
- [00:13:13.574]and three lane, a lot of traffic.
- [00:13:15.942]And again, I wanted to show that to show you
- [00:13:20.933]that in a modern roundabout, even a large complex one,
- [00:13:26.782]that the traffic flow was orderly.
- [00:13:33.719]I see we got to fix a little button here.
- [00:13:36.654]The traffic flow was orderly, not confusing
- [00:13:40.855]like at those big old circles.
- [00:13:43.414]Now this is a, let's see ...
- [00:13:45.824]They can see my arrow, right?
- [00:13:48.305]Yeah.
- [00:13:49.660]That outer ring is a big old traffic circle
- [00:13:52.655]in Kingston, New York, which was converted
- [00:13:54.767]to a modern roundabout.
- [00:13:56.201]And that circle in the middle is the modern roundabout
- [00:13:59.096]and it shows you the difference in size.
- [00:14:01.287]And you can see in that outer ring,
- [00:14:02.944]you can enter that thing.
- [00:14:05.638]It's a tangential entry.
- [00:14:07.305]You can maybe enter at 80 miles an hour if you wanted.
- [00:14:10.695]But this one has more deflection,
- [00:14:13.992]and most of the roundabouts maybe
- [00:14:16.377]have more deflection than this.
- [00:14:17.992]But it's a little hard to retrofit
- [00:14:20.631]some of these old circles.
- [00:14:23.257]And just the same one, it shows the dimensions.
- [00:14:25.648]You can see that the old circle had a 660 foot diameter.
- [00:14:30.473]The inner
- [00:14:32.577]roundabout conversion has 220 foot.
- [00:14:36.928]Generally 200 foot is considered the
- [00:14:42.185]kind of the maximum for a modern roundabout
- [00:14:45.413]although some of the three and four lanes ...
- [00:14:47.552]We don't have many of those in North America yet
- [00:14:50.287]but they're probably coming.
- [00:14:51.908]Again this shows you the difference.
- [00:14:53.438]On the red up there is the
- [00:14:57.867]tangential approach geometry
- [00:15:00.414]for that big old roundabout high speed entry.
- [00:15:03.316]More deflection on the modern roundabout,
- [00:15:06.460]clearly defined exits.
- [00:15:08.628]And again, if you go to that website
- [00:15:11.894]where they have the camcorder on that one in Halifax,
- [00:15:15.516]you could see all these things.
- [00:15:18.732]Again, Johnson City, I think this is also in New York.
- [00:15:23.285]I borrowed these slides from the New York state DOT
- [00:15:29.573]roundabout designer, Howard McCullough.
- [00:15:34.341]Now we also have another
- [00:15:36.331]another category of traffic circle.
- [00:15:40.701]And people in Manhattan particularly hate these.
- [00:15:43.155]The city engineer went out and put, I think,
- [00:15:46.380]seven of these around to control neighborhood speeding.
- [00:15:50.820]And that's what they're for.
- [00:15:51.981]You can think of them as analogous to a speed hump.
- [00:15:56.397]And they are.
- [00:15:57.358]Some of them are a little hard to get around.
- [00:15:59.198]Some of them are hard to make a left turn
- [00:16:00.960]to go around them.
- [00:16:02.639]Some cities let people turn in front of them.
- [00:16:06.512]But they're not a modern roundabout.
- [00:16:08.903]Now a quick comparison to the old rotaries,
- [00:16:11.118]you can see speeds ...
- [00:16:13.022]I did convert
- [00:16:17.691]the metric to the English roughly here.
- [00:16:21.729]40 to 50 mile an hour.
- [00:16:23.403]And the modern roundabouts, particularly the single lanes,
- [00:16:26.003]15 to 25.
- [00:16:28.211]Diameter: the old circles most of them
- [00:16:32.323]were greater than 200 feet.
- [00:16:34.458]And most of the modern roundabouts are less.
- [00:16:37.593]This is about 10 years old, but it's still
- [00:16:40.856]one of the best videos that I've ever run across
- [00:16:45.181]to explain what a modern roundabout is.
- [00:16:51.618]IIHS, Insurance Institute for Highway Safety.
- [00:16:55.692](video plays in background)
- [00:18:48.685]You'll notice that the flow is quite different
- [00:18:51.012]than what I showed you on those big old circles
- [00:18:54.500]in Massachusetts.
- [00:18:56.620]Here again is the sketch of the components
- [00:19:01.033]of a roundabout.
- [00:19:02.194]The important thing is the
- [00:19:08.642]inscribed circle diameter, or ICD.
- [00:19:11.933]That's from curb to curb across the center.
- [00:19:15.072]And of course the center island includes,
- [00:19:17.053]generally includes a truck apron.
- [00:19:20.705]So that we can keep it small, we'll talk a little bit later
- [00:19:24.927]about it's the deflection which starts
- [00:19:27.272]at the splitter island.
- [00:19:28.217]Back here we have a raised splitter island
- [00:19:30.929]which is generally
- [00:19:34.814]part of the definition of most roundabouts.
- [00:19:37.282]Once in a while, there's just one that's just painted
- [00:19:40.040]but it should be a raised splitter island.
- [00:19:44.052]This starts the deflection, and then the center island
- [00:19:49.688]continues the deflection.
- [00:19:50.975]So you basically have an S-curve here
- [00:19:53.543]where your prudent driver will slow down for curves
- [00:19:57.439]and the radius of the entry.
- [00:20:01.843]And the radius on the circle is what
- [00:20:04.660]slows these drivers down.
- [00:20:08.445]You can see we have a crosswalk here.
- [00:20:10.469]I'll show that a little bit later.
- [00:20:11.814]This one happens to ...
- [00:20:13.677]Where is that arrow?
- [00:20:15.910]This one happens to not be straight across.
- [00:20:18.523]It's perpendicular to the curb at that point.
- [00:20:21.669]The Access Board who
- [00:20:25.472]who enforces the Americans With Disabilities Act,
- [00:20:29.694]and we'll talk about some visually impaired pedestrians,
- [00:20:33.559]they'd like that to be straight across.
- [00:20:35.919]But different designers have different ideas.
- [00:20:38.726]Usually they're requiring a hedge or something here
- [00:20:43.359]to keep pedestrians from walking straight out there.
- [00:20:47.000]You don't want anything out here to encourage pedestrians
- [00:20:49.856]to walk out there.
- [00:20:51.530]This shows your entry curve and that blue line
- [00:20:55.574]is how you determine your fastest path through a roundabout.
- [00:20:59.158]There are some specific guidelines for that.
- [00:21:01.433]I'm gonna be careful.
- [00:21:03.439]Specific guidelines.
- [00:21:05.151]In other words, this should be
- [00:21:09.852]about 65 foot back from the stop line
- [00:21:14.560]and 1.5 foot from the painted line.
- [00:21:17.825]And in here, it should be five foot from any curb line
- [00:21:21.352]and like 1.5 foot from the circle.
- [00:21:23.889]That's how they put your radius in there to determine
- [00:21:26.369]your fastest path.
- [00:21:27.865]And then there's formulas you can determine the speed.
- [00:21:30.754]The other thing is of course the red
- [00:21:34.962]is your travels the way curvature
- [00:21:40.325]and then this green shows the curvature
- [00:21:43.432]for a right turn.
- [00:21:45.583]You don't want these to be too much different.
- [00:21:48.768]You don't want the driver
- [00:21:52.609]in the travels leg doing 15 miles an hour,
- [00:21:56.503]and a right turner here being able to do 50 or 60.
- [00:22:00.686]They say you should keep these
- [00:22:02.719]within 10 or 12 miles an hour for each of these.
- [00:22:07.486]Now this just shows a classic diagram
- [00:22:09.759]to show why these roundabout are safer
- [00:22:12.632]than a traditional intersection.
- [00:22:14.336]In a traditional intersection there's 32 conflict points:
- [00:22:17.454]eight diverging, eight merging, 16 crossing.
- [00:22:22.125]And at a modern roundabout, there's eight:
- [00:22:26.143]four diverging, four emerging.
- [00:22:28.870]Pedestrian conflict: you're walking across
- [00:22:31.911]a busy arterial, you got to watch in all directions.
- [00:22:34.646]In fact, I was walking across an arterial the other day
- [00:22:38.326]and out here on Anderson by West Loop,
- [00:22:41.856]it's not pedestrian friendly.
- [00:22:45.975]My head was swiveling trying to watch all ways for traffic.
- [00:22:49.152]But you got left turns, through and right turn movements
- [00:22:51.822]from the leg of the intersection, through movements
- [00:22:54.243]coming from the opposite side of the intersection,
- [00:22:56.783]right turns from the cross street,
- [00:22:58.928]left turns from the cross street, right turn on red.
- [00:23:02.209]So again, this shows those pedestrian conflicts
- [00:23:08.005]at a traditional intersection.
- [00:23:09.957]This kind of summarizes it all.
- [00:23:12.648]The less conflict points, the less chance for a crash.
- [00:23:16.445]It's just simple mathematics.
- [00:23:22.823]In a one lane roundabout, the advantage of a pedestrian
- [00:23:26.432]is that he only has to cross one lane of traffic at a time.
- [00:23:33.017]Get to the splitter island
- [00:23:34.583]and then look in the other direction.
- [00:23:36.895]Of course, if it's a two-lane approach,
- [00:23:38.552]at least he only has to look the direction.
- [00:23:40.705]He has to look two lanes for one direction.
- [00:23:43.570]This just shows that even at key intersections
- [00:23:46.594]there's less conflict points.
- [00:23:51.488]The single-lane crash, this was a study that was done.
- [00:23:55.856]It's getting quite old, but it hasn't been changed that much
- [00:23:58.775]even with recent data in it.
- [00:24:01.705]It's still quoted where the Insurance Institute
- [00:24:05.745]for Highway Safety, they looked at 24 signal
- [00:24:10.344]and stop sign intersections that were converted
- [00:24:13.355]to roundabouts.
- [00:24:15.242]And there was a 40% reduction in all crashes,
- [00:24:18.331]76% for injury crashes, and a projected 90% for fatal.
- [00:24:25.590]Actually the 40 was something like 38 or 39
- [00:24:28.905]rounded off to 40.
- [00:24:30.946]What you hear still quoted is 40, 80, 90,
- [00:24:34.511]or mostly the 40, 80.
- [00:24:36.816]It hasn't changed that much and I can show you that
- [00:24:39.256]in a little bit.
- [00:24:40.568]According to these figures, the roundabouts have
- [00:24:43.297]potential to save hundreds of thousands of injury crashes
- [00:24:47.159]and thousands of deaths.
- [00:24:48.979]Granted, once in a while,
- [00:24:50.554]especially if they're new in an area,
- [00:24:54.146]you might get an increase in fender benders.
- [00:24:57.938]But this reduction in injury crashes stays pretty constant.
- [00:25:03.571]And you
- [00:25:07.859]reduce the serious crashes substantially.
- [00:25:10.530]So the number one benefit of a roundabout,
- [00:25:13.808]and certainly in my mind and I think a lot of people agree,
- [00:25:19.193]is safety, safety, particularly injury crashes
- [00:25:23.046]and fatalities, including safer left turns.
- [00:25:27.545]You can look at the statistics too
- [00:25:29.257]and you look at all those intersection crashes
- [00:25:32.384]at traditional signal light intersections,
- [00:25:34.697]the highest percentage of all movement is a left turn.
- [00:25:39.567]And particularly
- [00:25:43.912]particularly for older drivers.
- [00:25:46.696]Anyway we don't have time to get into that that much.
- [00:25:49.289]But anyway, roundabouts have more efficient traffic flow,
- [00:25:53.777]increased capacity for a given level of demand,
- [00:25:56.810]less vehicle air pollution, pedestrian safety,
- [00:25:59.345]access management.
- [00:26:02.898]Access management is generally where you want
- [00:26:05.067]to prevent all your left turns
- [00:26:07.187]like on a strip mall.
- [00:26:10.681]So you put a barrier down the middle
- [00:26:13.180]so drivers can't take all those left turns.
- [00:26:15.908]Well they've got to have somewhere to turn around.
- [00:26:17.619]If you have a roundabout at each end,
- [00:26:20.985]that can go a long way to access management.
- [00:26:23.762]Also have aesthetics and landscaping,
- [00:26:27.017]walkability, better village atmosphere,
- [00:26:30.070]neighborhood traffic calming.
- [00:26:32.364]Traffic calming I think is a secondary benefit
- [00:26:34.886]of the modern roundabout.
- [00:26:36.869]The primary benefit is safety
- [00:26:39.374]and efficient traffic operation.
- [00:26:43.526]We'll look at that a little bit in a minute.
- [00:26:45.181]Anyway, these people that promote smart growth,
- [00:26:48.476]they also promote roundabouts.
- [00:26:50.213]They say it's a catalyst for smart growth.
- [00:26:54.133]Lower life cycle costs at many intersections.
- [00:26:56.845]I don't know if we have time to look at that.
- [00:26:58.301]These are more modern statistics.
- [00:27:00.429]Actually,
- [00:27:02.603]there wasn't much information around 2000
- [00:27:04.899]in the United States and North America.
- [00:27:08.682]So there was a big project to develop
- [00:27:10.474]this roundabout guide that came out about 1955.
- [00:27:14.988]But it's kind of interesting.
- [00:27:16.376]This is NCHRP a 572, that was the first edition.
- [00:27:20.686]It was kind of interesting, the improvements
- [00:27:24.453]in the knowledge about designing
- [00:27:30.261]the modern roundabout advanced so much
- [00:27:34.804]from 2000 to 2005
- [00:27:36.820]that as soon as the 572 hit the streets,
- [00:27:42.902]they decided there was need for an upgrade.
- [00:27:45.572]And so they immediately put out another contract
- [00:27:49.092]and upgraded.
- [00:27:50.158]So 672 which came out about a year ago
- [00:27:54.739]is the state of the art
- [00:27:57.058]for roundabout information and design.
- [00:28:01.793]And anyway, most of these statistics were broken down,
- [00:28:05.633]a little more broken down than what
- [00:28:07.828]the insurance men could study.
- [00:28:09.816]You can see where they looked at, in the case of signals,
- [00:28:13.425]they looked at all sites.
- [00:28:15.273]And again, a 35.4% reduction in all crashes,
- [00:28:21.738]75.8% reduction in injury and fatality.
- [00:28:28.322]Then they broke this down as much as they could,
- [00:28:31.835]like suburban signal lights,
- [00:28:33.568]there wasn't enough to do a good statistical analysis.
- [00:28:38.161]But in urban areas,
- [00:28:39.911]still a 60.1% reduction in injury crashes.
- [00:28:45.922]On two way stops, two way stops,
- [00:28:48.815]all 36 that they looked at,
- [00:28:51.221]again 44.2% reduction in all crashes,
- [00:28:55.870]81.8% in injury crashes.
- [00:28:59.311]And then they looked at rural and urban,
- [00:29:02.086]pretty similar results.
- [00:29:03.909]Suburban, urban, and you can see that all of the injury
- [00:29:09.486]and crash reductions are around 70% to 80%.
- [00:29:17.239]Really significant reduction.
- [00:29:19.703]Now I did skip over the all way stops.
- [00:29:24.512]Statistically, the modern roundabout ...
- [00:29:29.253]Admittedly the modern roundabout
- [00:29:33.317]does not prove to be any safer
- [00:29:37.518]than the four way stop.
- [00:29:39.932]But it sure beats the four way stop in efficiency.
- [00:29:43.992]In other words, who wants to stop at every intersection?
- [00:29:48.545]Although we can't sell a roundabout
- [00:29:53.195]over a four way stop
- [00:29:56.687]on the basis of safety, we sure can do it on the basis
- [00:29:59.597]of roundabout efficiency.
- [00:30:02.551]We'll look at it a little bit later.
- [00:30:04.644]Now just wanted to point out,
- [00:30:07.489]does everybody love roundabouts?
- [00:30:09.314]Now I hope.
- [00:30:11.828]Back around the late 90s, around 2000,
- [00:30:15.201]I started collecting comments from editorials
- [00:30:18.972]in the paper
- [00:30:24.037]and letters to the editor,
- [00:30:26.126]what I call the irrational opposition.
- [00:30:29.988]I didn't want to call these people kooky,
- [00:30:35.111]but it's irrational opposition anyway.
- [00:30:37.872]"If you build a roundabout, it will be the mother
- [00:30:39.484]"of all bad intersections.
- [00:30:41.072]"We could sell tickets to see it."
- [00:30:43.522]"They're easy to find; just look for a traffic jam
- [00:30:45.583]"and the ground piled up with broken glass and car parts."
- [00:30:49.796]This CARS Organization is very interesting.
- [00:30:53.308]It was an organization that was very prominent
- [00:30:57.636]in Hutchinson, Kansas
- [00:30:59.768]when they were talking about building a roundabout.
- [00:31:02.126]It stands for Citizens Against Roundabouts.
- [00:31:05.547]They had billboards and lawn signs all over town.
- [00:31:10.207]They really had a campaign.
- [00:31:12.449]Now you would think that they loved roundabouts.
- [00:31:16.696]We did a study of the first roundabout
- [00:31:20.674]that went in to Hutchinson, Kansas.
- [00:31:22.412]If you know anything about traffic engineering
- [00:31:25.507]and collision diagrams, this is a year and a half data
- [00:31:29.820]at this one intersection:
- [00:31:31.691]19 right angle crashes.
- [00:31:35.382]19, a year and a half.
- [00:31:37.718]Okay, they went and this is Hutchinson,
- [00:31:41.292]23rd and Severence in Hutchinson.
- [00:31:43.849]They built this beautiful roundabout.
- [00:31:47.520]I have mixed feelings about what's in the center island.
- [00:31:50.437]I'm kind of opposed to putting all kinds
- [00:31:53.047]of hard stuff in there.
- [00:31:55.386]But here again, once in a while you might have some nut
- [00:31:58.690]coming down there 80 miles an hour.
- [00:32:00.758]And he's gonna end up hung up on that statue.
- [00:32:03.559]But I don't know if we should design
- [00:32:05.134]for these people or not.
- [00:32:06.897]But here again, you'd think a year and a half after,
- [00:32:11.678]four fender benders.
- [00:32:13.835]Now you'd think that people would love it,
- [00:32:15.502]but they didn't.
- [00:32:16.866]In fact, this was voted in on like a five to four vote.
- [00:32:20.243]And these do get political.
- [00:32:22.675]An election came up right after.
- [00:32:25.516]And two or three of the city commissioners
- [00:32:27.994]that had voted for the roundabout were booted.
- [00:32:30.899]So they didn't get another one for 10 years,
- [00:32:34.386]about 10 years.
- [00:32:36.289]So there is some opposition.
- [00:32:37.549]We had some crazy opposition there.
- [00:32:39.305]I think even here in Manhattan.
- [00:32:41.133]I know you shouldn't mention this,
- [00:32:42.536]but out of our university:
- [00:32:46.240]our ex university president,
- [00:32:48.140]not our current one, they were saying things like,
- [00:32:52.476]"We don't want a roundabout.
- [00:32:53.693]"Parents will bring their prospective students
- [00:32:57.118]"to town, they see we have a roundabout,
- [00:32:59.012]"they'll send their kids somewhere else."
- [00:33:02.960]The Athletic Department was saying,
- [00:33:05.003]"Fans won't come here any more to our games
- [00:33:08.048]"if we have roundabouts."
- [00:33:12.134]I had a Vice President ...
- [00:33:13.728]I probably shouldn't say this but it always amuses me.
- [00:33:17.074]He's retired; we have a new administration.
- [00:33:20.647]I had a Vice President call me up about once a week
- [00:33:23.078]trying to convince me roundabouts weren't any good
- [00:33:26.354]and I should stop promoting them.
- [00:33:29.640]Anyway, now Maryland.
- [00:33:31.223]Maryland was one of the first states
- [00:33:32.690]that got into roundabouts.
- [00:33:34.194]In fact, back around 2000, they had 30 or 40
- [00:33:37.966]and I spent a couple of days driving
- [00:33:39.405]all over Maryland.
- [00:33:41.054]And at one time I had pictures and videos
- [00:33:43.952]of every one in Maryland.
- [00:33:46.636]They were the ones that got Kansas going.
- [00:33:50.259]They came to one of our transportation conferences
- [00:33:52.746]and our State Traffic Engineer went to Maryland.
- [00:33:56.103]And they decided, "Maybe we ought to put some in Kansas."
- [00:34:00.154]But look at before and after.
- [00:34:01.512]This is where they converted
- [00:34:03.266]from traditional traffic control.
- [00:34:06.606]The crashes per million entering vehicles before
- [00:34:10.026]totaled 1.53 million entering vehicles.
- [00:34:12.400]After, .97.
- [00:34:14.203]Injury, .48 per million entering vehicles, after: .11
- [00:34:19.689]This is just a fancy diagram of the same thing.
- [00:34:25.610]But the safety problems correctable by roundabouts:
- [00:34:28.594]right angle, head-on, left and through, and U turn;
- [00:34:30.835]high crash severity: injury or fatal;
- [00:34:33.102]sight distance or visibility problems which you can have
- [00:34:36.522]at a stop sign control;
- [00:34:38.993]inadequate separation of movements on approach;
- [00:34:41.763]and red light running.
- [00:34:42.765]No doubt about that.
- [00:34:44.844]I was pleased around 2000 at Discover Magazine.
- [00:34:48.238]And this was early in the growth
- [00:34:49.486]of the modern roundabout in North America.
- [00:34:53.706]"The modern roundabout may be the safest most efficient
- [00:34:55.993]"traffic control available today."
- [00:34:57.933]And I say it is.
- [00:35:01.795]It does depend on deflection, low speed,
- [00:35:03.702]and lane continuity.
- [00:35:06.765]And this is a bad example.
- [00:35:09.480]This is an example of one that ...
- [00:35:12.863]I don't even remember where it is
- [00:35:14.591]and I probably wouldn't say.
- [00:35:16.443]Do you see any deflection on that one approach in there?
- [00:35:20.386]None whatsoever.
- [00:35:21.828]That is not a good design.
- [00:35:24.294]So there are some bad ones.
- [00:35:25.579]There are a few bad ones out there.
- [00:35:27.857]Pedestrian safety.
- [00:35:29.333]Major studies have found no fatalities in U.S. roundabouts.
- [00:35:34.382]None.
- [00:35:36.425]I mentioned this before.
- [00:35:38.068]They cross one lane at a time.
- [00:35:39.707]At least cross traffic going in one direction at one time.
- [00:35:44.958]Even if they're hit, they're less likely
- [00:35:46.738]to be killed at low speeds.
- [00:35:49.262]And actually we have very little U.S. data
- [00:35:51.062]on pedestrian safety.
- [00:35:52.200]We don't walk a lot in this country.
- [00:35:54.551]And bicycles are even worse because we don't bicycle a lot.
- [00:35:59.716]But worldwide ...
- [00:36:01.139]And Australia was maybe one of the best examples.
- [00:36:04.917]My friend Andy O'Brien is a consultant down there.
- [00:36:08.109]In Melbourne,
- [00:36:10.591]in 1970, three roundabouts,
- [00:36:12.970]2000 at 3,000 roundabouts.
- [00:36:14.912]That's in the city; that's one city: 3000 roundabouts.
- [00:36:19.750]We did a study on traffic signals,
- [00:36:22.712]all the traffic signals in Melbourne:
- [00:36:26.516]five years, 1996 to 2000.
- [00:36:30.515]1,460 crashes involving pedestrians:
- [00:36:33.877]41 fatalities, 611 serious injuries.
- [00:36:38.417]Look at those roundabouts, 1996 to 2000.
- [00:36:43.048]A little over 1000 crashes: 57 involved pedestrians.
- [00:36:47.280]Zero fatalities, zero fatalities,
- [00:36:50.959]only 32 serious injuries.
- [00:36:53.131]So there's other proof in other countries
- [00:36:55.614]that they're safer for roundabouts.
- [00:36:57.737]This is out of Access Board.
- [00:36:59.511]I'll talk a little bit more about that later.
- [00:37:01.682]They would like that ...
- [00:37:03.098]They would like that straight across.
- [00:37:06.941]Of course on all curb carts you need an ADA compliant ramp.
- [00:37:11.863]You also need them at roundabouts to ...
- [00:37:15.264]Actually I don't have time to go into a lot of design.
- [00:37:17.892]But again this splitter island, it should be at least
- [00:37:21.828]a minimum of 50 foot long.
- [00:37:23.861]It should have a minimum of six foot width.
- [00:37:26.498]Generally it's six foot across by 10 foot
- [00:37:29.730]to allow for the pedestrian.
- [00:37:33.168]It should have some wayfinding here.
- [00:37:35.462]And this also has a bicycle ramp.
- [00:37:38.855]We'll talk a little bit more about that later.
- [00:37:46.196]Here it is: a bicycle lane coming down the approach.
- [00:37:52.368]Bicycle lanes should end at least 100 feet
- [00:37:57.215]before the entry to the roundabout.
- [00:38:01.786]So a bicycle has its choice.
- [00:38:03.946]He can drive through the roundabout like a vehicle.
- [00:38:08.305]Or, if he's a novice or doesn't feel comfortable,
- [00:38:13.911]he can become a pedestrian, take that ramp,
- [00:38:15.729]get on the sidewalk and become a pedestrian.
- [00:38:18.295]It's somewhat controversial, where the crosswalk should be.
- [00:38:21.832]Traditionally, it's put one car length
- [00:38:24.295]behind the yield line, one car length behind the yield line.
- [00:38:28.357]And generally pretty much straight across,
- [00:38:30.551]or at least it might be tilted a little bit here and there.
- [00:38:35.374]Now there was a big research project and he,
- [00:38:38.751]he claimed the terms proximal and distal
- [00:38:43.080]where if you put it up here near the yield line,
- [00:38:45.880]maybe one car back would be the closest,
- [00:38:48.239]he called it a proximal.
- [00:38:50.557]And then he looked at some back aways here,
- [00:38:54.329]he called them distal.
- [00:38:55.722]The advantage of this, if you have the crosswalk up here,
- [00:38:59.648]the entry is no problem.
- [00:39:01.031]But on exiting there could be a problem
- [00:39:04.949]backing cars up into the roundabout
- [00:39:07.289]if there's a lot of pedestrians here.
- [00:39:09.485]So the effective of putting this zigzag crossing in
- [00:39:13.303]is to give more storage room for exiting vehicles
- [00:39:17.426]so they won't back up in a roundabout.
- [00:39:19.568]But anyway, it's still a little ...
- [00:39:24.040]I don't know if it's controversial
- [00:39:25.266]but different designers have different opinions.
- [00:39:27.755]In fact a lot say if it's a two lane approach,
- [00:39:30.185]the crosswalk should be two car lengths back instead of one.
- [00:39:35.670]Now the visually impaired ...
- [00:39:37.756]Around 1990
- [00:39:41.189]we passed this ADA,
- [00:39:43.274]Americans with Disabilities Act.
- [00:39:45.534]For the first 10 or so years, the Access Board
- [00:39:48.729]is an organization
- [00:39:52.716]authorized by Congress
- [00:39:57.622]to enforce the ADA Act.
- [00:40:02.473]And they have very
- [00:40:06.616]very strong power to do so.
- [00:40:10.493]And along about 2000, when roundabouts started
- [00:40:14.884]to come more into existence,
- [00:40:20.195]they decided that they were not accessible
- [00:40:23.416]to the visually impaired.
- [00:40:25.686]Okay, let's say from 1990 to 2000,
- [00:40:28.546]they mostly did building standards.
- [00:40:30.795]You know that all buildings have to be accessible.
- [00:40:33.757]You have to have handicapped parking and so forth and so on.
- [00:40:38.634]Starting about 2000, they started looking
- [00:40:42.245]at the public rights of way.
- [00:40:45.413]And that's what the PROWAG,
- [00:40:47.670]Public Rights of Way Accessibility Guidelines.
- [00:40:50.416]This is in final draft form right now.
- [00:40:52.674]They've been working on it for 10 years.
- [00:40:55.889]And they do say that blind people have difficulty
- [00:40:58.308]finding the crossing, arriving with the crossing,
- [00:41:02.854]judging traffic, and evaluating gaps.
- [00:41:06.651]So with roundabouts, again the crossing
- [00:41:09.721]is a little bit set back from a normal crossing.
- [00:41:14.878]So there has to be some wayfinding.
- [00:41:16.905]They say traffic sounds aren't clear.
- [00:41:19.154]There's traffic going in different directions
- [00:41:22.800]so they have trouble.
- [00:41:26.952]And there's problem with gap creation and gap detection.
- [00:41:34.854]Okay, on the first draft, the Access Board said,
- [00:41:38.070]"There shall be pedestrian signals on all legs
- [00:41:40.392]"of all roundabouts,"
- [00:41:41.767]which really upset a lot of traffic engineers.
- [00:41:44.569]I have a list here and for the first five years,
- [00:41:47.330]most of the back and forth was about
- [00:41:51.878]this Access Board requirement.
- [00:41:54.475]Later drafts they kind of backed off and said,
- [00:41:57.806]"all legs of two or more lane roundabouts."
- [00:42:00.642]And also they calmed the traffic engineers a little bit.
- [00:42:03.851]They said, "Okay, we're not gonna insist that you have
- [00:42:06.538]"the traditional full blown
- [00:42:10.521]"green, yellow, red signal,
- [00:42:13.225]"but we want something that's accessible."
- [00:42:16.651]So their latest language, they okayed the HAWK signal
- [00:42:21.354]which now is officially
- [00:42:24.270]the NADTC pedestrian hybrid signal.
- [00:42:27.233]They say "or equivalent control."
- [00:42:29.364]But they haven't really defined equivalent control.
- [00:42:32.522]I'm on a task force with the ITE.
- [00:42:35.142]We're trying to do a white paper to help the Access Board
- [00:42:38.834]determine what equivalent control is.
- [00:42:42.018]But they have blessed this pedestrian hybrid signal.
- [00:42:46.717]Many people still call it the HAWK.
- [00:42:48.499]It's better than Tucson.
- [00:42:50.476]And it got the name HAWK for some reason.
- [00:42:52.897]And I've been told HAWK doesn't ...
- [00:42:54.275]It's not an acronym because
- [00:42:55.882]it doesn't really stand for anything.
- [00:42:58.971]Somebody said, "Hey, let's call it a HAWK."
- [00:43:01.142]And so that was it.
- [00:43:02.743]How it works: it's dark until a pedestrian
- [00:43:06.288]pushes the button.
- [00:43:08.349]We did some research down in Lawrence,
- [00:43:09.985]but not on a roundabout.
- [00:43:11.220]We did it at mid-block pedestrian crossing.
- [00:43:14.156]In Lawrence they turned out well.
- [00:43:16.654]And Lawrence had six or seven of them
- [00:43:18.451]and it didn't block stuff.
- [00:43:19.452]Anyway, they're dark until a pedestrian pushes the button.
- [00:43:24.934]And traffic engineers don't like that.
- [00:43:27.940]They say drivers are supposed to stop at a dark signal.
- [00:43:32.198]But then a pedestrian pushes the button,
- [00:43:35.205]it flashes yellow, and then it flashes red.
- [00:43:38.904]Excuse me, it comes on solid red.
- [00:43:42.824]But then after a few seconds, it turns to flashing red.
- [00:43:46.453]The advantage of that,
- [00:43:51.196]the driver can go ahead on flashing red
- [00:43:54.870]if there's no pedestrian.
- [00:43:56.020]You can see it out here, and maybe by a lot of universities,
- [00:44:00.340]a student will push the button and run across the street
- [00:44:03.211]and you're sitting there 20 or 30 seconds after he's gone.
- [00:44:08.702]It's still a solid red and you still have to be stopped.
- [00:44:11.752]If they had a HAWK there, and I've heard they're thinking
- [00:44:15.757]of putting one out here.
- [00:44:17.071]I don't know if they'll ever get around to it.
- [00:44:18.746]Anyway we did some studies.
- [00:44:21.058]We've been doing this since 1997.
- [00:44:23.913]This is the first one ...
- [00:44:24.746]The first roundabout in Kansas was in Manhattan, Kansas,
- [00:44:29.978]Candlewood and Gary about 1997, 1998.
- [00:44:34.589]The primary focus of our research ...
- [00:44:39.854]Our research concluded that the roundabout there
- [00:44:43.068]was better than any other thing they could have put there.
- [00:44:45.406]We also had a study.
- [00:44:46.530]We looked at 11 roundabouts in Kansas
- [00:44:49.223]that had stop and signal control.
- [00:44:53.361]And these results were very good,
- [00:44:56.306]helped establish that even at low traffic volumes,
- [00:44:58.717]modern roundabouts are a beneficial device.
- [00:45:02.536]I just want to show the results.
- [00:45:03.832]This is the average of the 11.
- [00:45:05.352]You can see measures of effectiveness.
- [00:45:07.910]We used average intersection delay;
- [00:45:10.368]maximum approach delay;
- [00:45:12.564]queue length; degree of saturation
- [00:45:15.798]which is a volume to capacity ratio;
- [00:45:18.381]proportion stopped.
- [00:45:19.732]You can see that the roundabout decreased the delay
- [00:45:24.247]in stopping, you can see 40% to 70%.
- [00:45:28.838]We also looked emissions.
- [00:45:31.114]These are the major pollutants from vehicles.
- [00:45:34.353]We looked at the emissions.
- [00:45:37.417]Again you can see a reduction in all of the emissions
- [00:45:40.358]which are from motor vehicles: 30% to 53%.
- [00:45:46.335]Again there was another recent IIHS study
- [00:45:51.107]that looked at 10 roundabouts Kansas, Maryland, Nevada:
- [00:45:54.940]20% reduction in delay;
- [00:45:58.179]13% to 23% reduction in delay per vehicle;
- [00:46:01.340]14% to 43% reduction in proportion stopped.
- [00:46:05.804]They also concluded that energy ...
- [00:46:09.286]And I believe there are energy savings
- [00:46:10.997]with modern roundabouts.
- [00:46:12.797]They said they looked at 10 intersections.
- [00:46:18.308]They concluded that with a modern roundabout,
- [00:46:20.922]each vehicle delay would be one minute less.
- [00:46:24.286]And that, just doing the math that converted
- [00:46:26.969]to an annual delay savings to the motorist
- [00:46:30.613]of 325,000 hours
- [00:46:33.806]and 235,000 gallon of gas a year.
- [00:46:38.758]Bicycle conflicts: U.S.A. experience with bicycles
- [00:46:42.008]is very limited.
- [00:46:43.356]I'm getting short of time so I'm gonna speed up here
- [00:46:45.417]a little bit.
- [00:46:46.560]We don't have a lot of experience with bicycles
- [00:46:49.325]Although I mentioned before, a bicyclist can
- [00:46:53.137]either become a pedestrian and walk his bike
- [00:46:56.047]like a pedestrian.
- [00:46:56.946]Or if he feels brave or experienced, he can ride.
- [00:47:01.277]In the Netherlands where they have thousands of bicyclists,'
- [00:47:04.174]they do a more elaborate bicycle path around.
- [00:47:08.871]In one concept,
- [00:47:13.212]the bicyclist has the right of way
- [00:47:15.548]and entering vehicles have to stop.
- [00:47:17.907]In the other, the bicycles don't have the right of way
- [00:47:21.543]and exiting vehicles don't have to stop.
- [00:47:23.865]The bicyclists stop.
- [00:47:25.772]Public acceptance.
- [00:47:28.583]The IIHS has done some of these studies.
- [00:47:31.908]And they've generally found in ...
- [00:47:34.643]This was a study where the first roundabout was going in
- [00:47:39.152]in about six states and they had a public relations firm
- [00:47:44.653]to see if people favored or not favored.
- [00:47:47.459]You can see, before the roundabout went in,
- [00:47:49.996]31% were strongly or somewhat in favor.
- [00:47:53.245]And 55% were strongly opposed.
- [00:47:57.104]It almost flipped afterwards.
- [00:47:58.859]Where after it went in and people used it,
- [00:48:02.928]63% strongly favored and still 28% against.
- [00:48:06.986]You're always gonna have against.
- [00:48:09.801]The conclusion was that after construction added
- [00:48:13.099]to the change to be more positive.
- [00:48:14.960]But I think the public needs more education
- [00:48:22.695]and, as I said, I showed that again
- [00:48:24.800]because I worked two studies where they studied crashes.
- [00:48:29.733]And approach geometry and deflection was very important.
- [00:48:33.854]I'm gonna skip the history.
- [00:48:35.403]I think I've got 10 minutes for questions.
- [00:48:37.663]I'm supposed to leave 10 or 15 minutes for questions.
- [00:48:41.300]And I put the history ...
- [00:48:43.368]I love this history part but we can,
- [00:48:45.952]we'll have to do without the history at this time.
- [00:48:49.938]But circular intersections have been around
- [00:48:52.757]since the Middle Ages.
- [00:48:54.115]But they're not all modern roundabouts.
- [00:48:56.419]So don't let people tell you,
- [00:48:58.452]"Hey these circles don't work in New Jersey.
- [00:49:00.680]"They don't work in Massachusetts.
- [00:49:02.752]"The Arc de Triomphe doesn't work."
- [00:49:05.027]These are not modern roundabouts.
- [00:49:08.008]Okay, thank you.
- [00:49:13.163](audience member speaks in background)
- [00:49:17.908]Okay, alright.
- [00:49:31.210]Gene, thank you for that presentation.
- [00:49:33.323]Very informative as always.
- [00:49:36.113]Clearly, roundabouts ...
- [00:49:37.821]I think you've made your point.
- [00:49:38.654]Roundabouts are pretty important in the toolbox.
- [00:49:42.701]Could you give us some advice, or your thoughts?
- [00:49:45.642]Are there any times when they're not appropriate
- [00:49:48.903]at, let's say, a signal lighted intersection,
- [00:49:50.236]converting it to a roundabout?
- [00:49:52.692]Well, a lot of downtown areas
- [00:49:54.615]where you don't have the room,
- [00:49:55.940]I think it would be
- [00:50:00.087]unreasonable to knock down buildings
- [00:50:01.966]just to put one in downtown.
- [00:50:04.542]Although you can put some smaller ones in downtown.
- [00:50:07.071]I haven't got into mini roundabouts.
- [00:50:10.302]Mini roundabouts are almost the size
- [00:50:13.298]of these small traffic circles today
- [00:50:17.015]except they're not raised.
- [00:50:19.356]And there's maybe an inch or two hump
- [00:50:24.096]where a vehicle can go right over it.
- [00:50:26.186]I don't know if we're ready for these in the United States.
- [00:50:30.118]Some people say if your slope
- [00:50:33.403]if the slope of your intersection ...
- [00:50:38.129]Well we don't have a lot of intersections
- [00:50:39.632]on a real high slope, but you'd need
- [00:50:41.243]to be careful of that.
- [00:50:48.494]And I think that most intersections where you have space
- [00:50:55.074]and where acquiring space is not extremely expensive
- [00:51:00.005]or undesirable.
- [00:51:02.193]There are places where you wouldn't want to,
- [00:51:09.781]even in the country, you wouldn't want to tear up land
- [00:51:15.601]to make room for a roundabout.
- [00:51:20.197]I think it has to do mostly with space and economics.
- [00:51:29.655]Okay we have a couple of questions
- [00:51:31.168]from online.
- [00:51:32.111]Under what type of roads do you think roundabouts
- [00:51:34.294]are most appropriate to apply?
- [00:51:39.432]Probably rural,
- [00:51:43.716]probably rural or relatively high speed locations.
- [00:51:48.648]That's where you're gonna have most of your serious crashes.
- [00:51:54.481]And what do you think
- [00:51:55.471]of consecutive roundabouts in arterial
- [00:51:57.619]with respect to safety and traffic progression?
- [00:52:03.859]Where? Did you say in Australia?
- [00:52:05.633](audience member speaks in background)
- [00:52:10.160]There can be a problem in a corridor
- [00:52:14.675]where you have signals and roundabouts.
- [00:52:18.793]So that could be a problem with your progression.
- [00:52:23.081]I don't think ...
- [00:52:24.379]We're getting where we're putting more and more roundabouts
- [00:52:27.851]in corridors and I think that, I think that's gonna be fine.
- [00:52:33.224]There is a $300,000 or $400,000 NCHRB study
- [00:52:38.389]underway now looking at roundabouts in corridors.
- [00:52:41.549]And they should have some definite answers.
- [00:52:43.270]And Kittelson is doing that study
- [00:52:46.144]and they're about in the middle of it.
- [00:52:48.935]I might also mention there is another big study coming up,
- [00:52:52.888]a $300,000 or $400,000 study,
- [00:52:55.307]to look at the life cycle costs of all types
- [00:53:00.660]of intersection traffic control.
- [00:53:02.652]It will give us some better answers
- [00:53:04.982]on what is the best solution,
- [00:53:14.121]as Larry said, in the traffic engineer's toolbox
- [00:53:18.290]in terms of life cycle cost.
- [00:53:20.314]But here again, if you ...
- [00:53:24.902]This research should answer the question:
- [00:53:29.073]"What should you have in a benefit-cost ratio?"
- [00:53:33.263]The benefit-cost ratio is simple mathematics
- [00:53:36.279]but coming to some consensus
- [00:53:40.387]of what to put in the benefits
- [00:53:42.300]and what costs you put on a benefit.
- [00:53:44.542]If you put lives and injuries saved
- [00:53:49.663]and used the traditional Federal Highway costs
- [00:53:52.176]for deaths and injuries,
- [00:53:56.084]I can't see that most other traffic control
- [00:53:58.108]is gonna come out
- [00:54:01.388]economically better than a modern roundabout
- [00:54:07.706]when you consider death and you put a price on it.
- [00:54:14.085]Those past two questions are actually
- [00:54:15.721]from the University of Nebraska.
- [00:54:17.486]Now we have a question from the University of Iowa.
- [00:54:21.023]Is there any intersection that you would not recommend
- [00:54:23.805]a roundabout: like for one-way streets, et cetera?
- [00:54:32.075]Well,
- [00:54:37.083]I can't think of any.
- [00:54:42.622]A roundabout is a series of one-way streets
- [00:54:46.358]if you want to look at it that way.
- [00:54:48.575]I mean if you open up the circle
- [00:54:54.167]into a straight line and all of your legs are coming in,
- [00:54:58.363]and they're all right turns,
- [00:55:01.454]and the traffic in your circle
- [00:55:03.944]is all going to the right,
- [00:55:05.727]it's just like coming into a T intersection,
- [00:55:09.955]two one-way streets coming into an intersection.
- [00:55:13.240]I think I showed
- [00:55:16.215]they can be put into three intersections.
- [00:55:18.836]There has to be a little moving them around
- [00:55:23.371]to get the deflection and to kind of have room to do that.
- [00:55:27.648]Yeah I think they'd would work on one-way intersections
- [00:55:33.342]and one-way streets.
- [00:55:37.203]Okay, we have another question
- [00:55:38.572]from Steve McLemil.
- [00:55:40.988]What answers do you have for the criticism of roundabouts
- [00:55:44.164]for oversized loads on rural highways?
- [00:55:48.563]They can be accommodated.
- [00:55:49.977]We just finished a study.
- [00:55:52.372]The report is being reviewed by Kansas on oversize
- [00:55:55.854]overweight vehicles at roundabouts.
- [00:55:58.835]And they can be accommodated and usually
- [00:56:01.974]without a lot of extensive tape.
- [00:56:07.099]And again the simplest
- [00:56:13.055]way of accommodation
- [00:56:15.767]is to increase the size of the truck apron.
- [00:56:20.921]In other words, make the truck aprons more than 30 feet.
- [00:56:24.173]You can get a lot of oversize overweight loads
- [00:56:28.953]through the roundabout by using the very large truck apron.
- [00:56:34.066]There are other techniques by letting them go the wrong way.
- [00:56:38.117]You say, "Well that's dangerous."
- [00:56:40.194]Well oversize overweight loads are usually escorted.
- [00:56:44.502]And so there would have to be some traffic control.
- [00:56:47.519]But again, it depends on the turn that they're making.
- [00:56:51.696]But all I can say at this time
- [00:56:53.631]without going into a lot of detail is
- [00:56:56.381]that in all cases that I know of,
- [00:56:59.980]they can be accommodated.
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