RE: Roundabouts?

[Robert Leone]

Dear Randos:
They put FIVE Roundabouts (starting with only three) in La Jolla Blvd
(a two lane road at that point) -- which is on the route to work when I
take the bus. I can't type the language the drivers used the first week
they were driving that (after the detour onto La jolla hemosa). Now they
seem to be using articulated (accordiion-middleed extra long buses) on
that route on weekends.
In the meantime, they're putting roundabouts on the side streets to
discourage the street racers sor something. I admit I "take the lane"
through the roundabout section of La Jolla Blvd when I ride through
there, as it also features diagonal parking where there's not a
roundbout. I'm not a fast rider, so I can palpably feel the rage of the
slowed motorists behind me -- somethimes they figure out what's
happneing when I brake at the roundabouts for the cars that HAD gapped
us out of the previous traffic circle.

Robert Leone

[Donald Perley]

Gmail puts a targeted link (advertisement, but just the link, no
graphics) over each email. This one rated a roundabout design firm.
They say:

"Nothing defines the new traffic engineering landscape like the modern
roundabout. Benefits related to safety, aesthetics, traffic
operations, and cost make the modern roundabout a desirable feature
for many of our public roadways. More and more local, State, and
Federal agencies are studying and building modern roundabouts in their
jurisdictions."

[WMdeR]

Dear Robert,

My experience with roundabouts has not been yours. I prefer them for
cycling, as long as they've been properly designed (basically, if
they're big enough--we're not talking about traffic-calming devices
like traffic circles), and drivers (both motorized and otherwise) have
become familiar with them. Those are both fairly serious conditional
statements here in the United States, where roundabout design and use
has not been common.

Here's why I like them for cycling: They're safer. Really.
1. The design eliminates the left hook. No oncoming traffic.
2. The smaller (intersection of two-lane roads) ones have maximum
safe speeds close to my traveling speed. I take the lane when I
approach them, and, consequently, no right hook.
3. They don't back up cars waiting for the light to change, so
frustration levels go down, and cyclists are seen as "taking their
turn" rather than sidling up to the stop line to the right of a long
line of cars.

I prefer them when driving a motor vehicle for similar reasons.

They're not so fine for pedestrians, though.

Disclaimer: My engineering firm (though not my office) has designed
roundabouts and had good success with them.

Best Regards,

Will

William M. deRosset
RUSA 2401

On Feb 5, 6:15 am, Donald Perley <per...@comcast.net> wrote:
> Gmail puts a targeted link (advertisement, but just the link, no
> graphics) over each email.   This one rated a roundabout design firm.
> They say:
>
> "Nothing defines the new traffic engineering landscape like the modern
> roundabout. Benefits related to safety, aesthetics, traffic
> operations, and cost make the modern roundabout a desirable feature
> for many of our public roadways. More and more local, State, and
> Federal agencies are studying and building modern roundabouts in their
> jurisdictions."
>

[Mike Biswell]

In USA a roundabout gives the vehicle on the left the right of way, but in
all other traffic situations the vehicle on the right has the right of way.

Confusion!

[john mangin]

I am a fan of roundabouts for many of the previously mentioned reasons, both as a cyclist and as a driver.  However, I have often wondered why it is so common that bike lanes leading into a roundabout are so commonly eliminated.  Any thoughts? 

> Date: Thu, 5 Feb 2009 11:55:34 -0800
> To: mikeb...@comcast.net; ran...@googlegroups.com
> From: hei...@earthlink.net
> Subject: [Randon] Roundabouts?

> Put a yield sign at each entrance of the roundabout, and the
> confusion is resolved. Yield signs trump the "Right has right-of-way"
> rule. I believe that is how it is done in WA State at the few
> roundabouts we have.
>
> Jan Heine
> Editor
> Bicycle Quarterly
> 140 Lakeside Ave #C
> Seattle WA 98122
> http://www.vintagebicyclepress.com
>
>

[WMdeR]

Dear All,

I should have posted this link when I posted above.

http://mutcd.fhwa.dot.gov/HTM/2003/part3/part3b2.htm#figure3B27

The diagrams show standard roundabout signage (from which you can
infer the intended traffic flow) for the United States.

Best Regards,

Will

William M. deRosset
RUSA2401

On Feb 5, 1:11 pm, john mangin <ljman...@hotmail.com> wrote:
> I am a fan of roundabouts for many of the previously mentioned reasons, both as a cyclist and as a driver.  However, I have often wondered why it is so common that bike lanes leading into a roundabout are so commonly eliminated.  Any thoughts?  > Date: Thu, 5 Feb 2009 11:55:34 -0800> To: mikebisw...@comcast.net; ran...@googlegroups.com> From: hein...@earthlink.net> Subject: [Randon] Roundabouts?> > > At 11:38 AM -0800 2/5/09, Mike Biswell wrote:> >In USA a roundabout gives the vehicle on the left the right of way, but in> >all other traffic situations the vehicle on the right has the right of way.> >> >Confusion!> > Put a yield sign at each entrance of the roundabout, and the > confusion is resolved. Yield signs trump the "Right has right-of-way" > rule. I believe that is how it is done in WA State at the few > roundabouts we have.> > Jan Heine> Editor> Bicycle Quarterly> 140 Lakeside Ave #C> Seattle WA 98122>http://www.vintagebicyclepress.com> > _________________________________________________________________
> Windows Live™: E-mail. Chat. Share. Get more ways to connect.http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t2_allup_explore_022009

[Steve Palincsar]

On Thu, 2009-02-05 at 11:55 -0800, Jan Heine wrote:
> At 11:38 AM -0800 2/5/09, Mike Biswell wrote:

> Put a yield sign at each entrance of the roundabout, and the
> confusion is resolved. Yield signs trump the "Right has right-of-way"
> rule. I believe that is how it is done in WA State at the few
> roundabouts we have.

Actually, not always.

In Virginia, "[w]hen two vehicles approach an intersection not
controlled by traffic lights or signs, neither vehicle has the
right-of-way. Generally, Virginia law states that when two
or more vehicles approach an uncontrolled intersection from different
directions at the same time, the driver on the LEFT must yield to the
driver on the right. ... The law does not give the right-of-way to
anyone. It only states which driver must yield to another.

"Roundabouts, rotaries, and traffic circles are intersections that are
controlled by a circular island in the center. Circular intersections
may have one or more lanes. Entering traffic must yield the right-of-way
to circulating traffic."

--http://www.dmv.virginia.gov/webdoc/pdf/manual/sec-2.pdf

And then there's Boston, where the only rule that applies to roundabouts
seems to be "If the driver in front of you isn't going fast enough for
you, ram him".

[pate...@yahoo.com]

....and I always thought that the rule was international: the vehicle in the circle (roundabout, rotary or whatever term you use locally) has the right of way and the vehicle entering the circle must yield thereto.

Thus it applies to everyone regardless of which side of the road one is legally permitted to drive...Massachusetts excepted!


--- On Thu, 2/5/09, Steve Palincsar <pali...@his.com> wrote:

[Randon Nerd]

Don't blame Massachussets for Rotaries...from Wikipedia but it pretty
much sums up the points others are making ... New Jersey at one point
had a total of 101 traffic circles. In the 1920s and 1930s, New
Jersey felt that traffic circles were an efficient way for moving
traffic through three or more intersecting roads. Many of these
interchanges are rotaries in design, as opposed to the more successful
modern roundabout.

As suburban and rural populations grew New Jersey's traffic circles
became outdated. The increased number of drivers on the roads resulted
in traffic circles being more likely to hinder traffic than help it.
Increased number of vehicles and faster traffic speeds made traffic
circles more dangerous and accidents common. Many traffic circles
became notorious for having frequent accidents and being confusing,
especially for non-locals. Not helping the confusion is the state has
no official rules for using traffic circles. Starting around the
1970s, the New Jersey Department of Transportation began phasing out
traffic circles. Common methods of eliminating traffic circles are
building a road through the circle, adding traffic lights, and the use
of grade separation.

I found it interesting that as the US is phasing out traffic circles
to make roads safer, the EU is embracing them in the interest of
traffic safety.

[Steve Palincsar]

On Thu, 2009-02-05 at 21:31 -0500, Randon Nerd wrote:
> Don't blame Massachussets for Rotaries...from Wikipedia but it pretty
> much sums up the points others are making ... New Jersey at one point
> had a total of 101 traffic circles. In the 1920s and 1930s, New
> Jersey felt that traffic circles were an efficient way for moving
> traffic through three or more intersecting roads. Many of these
> interchanges are rotaries in design, as opposed to the more successful
> modern roundabout.
>
> As suburban and rural populations grew New Jersey's traffic circles
> became outdated. The increased number of drivers on the roads resulted
> in traffic circles being more likely to hinder traffic than help it.
> Increased number of vehicles and faster traffic speeds made traffic
> circles more dangerous and accidents common. Many traffic circles
> became notorious for having frequent accidents and being confusing,
> especially for non-locals. Not helping the confusion is the state has
> no official rules for using traffic circles. Starting around the
> 1970s, the New Jersey Department of Transportation began phasing out
> traffic circles. Common methods of eliminating traffic circles are
> building a road through the circle, adding traffic lights, and the use
> of grade separation.
>
> I found it interesting that as the US is phasing out traffic circles
> to make roads safer, the EU is embracing them in the interest of
> traffic safety.

There's evidently a big difference between rotaries and traffic circles,
and who has the right of way proceeding through them is one difference
(according to Wikipedia's article). They're in vogue in the metro
Washington DC area. A new one was built near Chaptico MD just last
year, and on one stretch of new road in Maryland north of the District
of Columbia there are four or five in what can't be more than a mile.

Having experienced the Chaptico intersection for almost 30 years, I have
to say, the rotary is a tremendous improvement over the stop signs and
flashing lights they had before. Traffic in the rotary moves at bicycle
speed and it's easy to get through, when before you had to cross motor
traffic moving at 50-65 mph.

[Dark Horse]

> Put a yield sign at each entrance of the roundabout, and the
> confusion is resolved. Yield signs trump the "Right has right-of-way"
> rule. I believe that is how it is done in WA State at the few
> roundabouts we have.

Except for all the passive-aggressive idiots who think that "Stop" is
spelled Y-i-e-l-d.
Those signs are starting to have the same bottlenecking effect as
"merge" signs around these parts.

Dark Horse

[M-SADLER]

As a bike rider in the United Kingdom, where there are possibly more
roundabouts than you could imagine in your worst nightmare, the majority of
them are extremely hazardous for cyclists. A major problem seems to be
that car drivers enter roundabouts at too high a speed and in many cases do
not see (or ignore) a cyclist already on the roundabout. IMO the only
"safe" place for a cyclist is to ride is as near to the centre of the
roundabout as possible, but getting there and out of there can be highly
suspect!
There is also in the UK a proliferation of "mini-roundabouts" which are
merely painted in the road, the majority of drivers just drive straight over
them.

The most effective method of controlling traffic entering roundabouts I have
witnessed is in certain areas of France where they put a large "Hump" at the
entry to the roundabout, this ensures that the vehicles do stop!

M-SA...@sky.com

[Ingle, Bruce]

The advantage of a roundabout is that it theoretically allows two roads
to intersect at speed without grade separations, but in order to be
effective (ie, not cause delays) they need to have a pretty significant
diameter (think a mile or so for highway speeds). Here in the
Northeast, land is at a premium, so rotaries are generally undersized
and cause significant delays as a result. It appears some are being
eliminated where finances permit, but these days highway departments are
lucky if they have enough money to keep the holes filled:

http://archive.capecodonline.com/special/360_view/sagamore/rotaryno21.ht
m

We also have some local rotaries with signals which provide the worst of
both worlds -- poor use of real estate combined with even greater
traffic delays.

The Boston 600km route has a few rotaries; fortunately, we go through
most of them early in the morning.

France has cornered the market on undersized roundabouts (both for size
and frequency).

- Bruce

[Emily O'Brien]

Here in Karlsruhe there's an interesection that seems to be half
rotary, half intersection. It mostly looks like a rotary, in that two
streets cross at a circle , which is paved in asphalt, and the middle
of the circle is cobblestones with a statue in the middle. However,
there's no curb between the asphalt and the cobbles, and the above-
ground tram tracks that go down the middle of the larger of the two
streets just deflect slightly around the statue, but mostly go
straight. This means that 75% of the traffic on the smaller street
thinks it's a rotary, and 75% of the traffic on the larger street just
drives straight through like the tram tracks. On top of that, very
often cyclists going straight on the smaller street very frequently
cross the intersection in an unpredictable line (since they're dodging
traffic and trams) on the wrong side of the statue, so if you're
riding through more or less like you would go through a rotary, you
suddenly see another cyclist coming straight at you. Talk about the
worst of both worlds!

I have to say that I have very mixed feelings about circles and
rotaries. When they're matched well with the number of streets and
the traffic flow, they mean that I can go in and out without having to
wait through six different parts of a complicated signal cycle, and
very often everyone can get in and out without having to come to a
complete stop. This is a good thing. But there are other places
where the traffic is too heavy for the size of the circle and it
becomes extremely difficult to enter the rotary, and then get out of
it where you want to.
I think that more important than a distinction between a traffic
circle and a rotary is the size of the circle compared to the number
of cross streets and the amount of traffic flow.

Jake has very often suggested an "exciting" idea for a brevet route,
consisting entirely of laps on a traffic circle with a control at each
end.....

Emily "Going 'round in circles" O'Brien

[Donald Perley]

It depends on what you are comparing to by "not cause delays."
Compared to driving straight through, or compared to a 6-way
intersection with traffic light where each incoming stream gets to go
1 at a time?

A lot of places I've seen in New England make up a roundabout by
making existing roads surrounding the village green (for example ) 1
way.

In (Old) England I saw a lot of just plain 4 corner intersections
declared to be "mini-roundabouts" by putting up a sign and some arrows
on the pavement.

[WMdeR]

Dear All,

(Long, opinionated post, only tangentially related to randonneuring,
but isn't traffic engineering cool and dear to all our hearts?).

I prefer the "modern" roundabout. Rotaries and traffic circles are
different things. Roundabouts are designed to have maximum safe
speeds of 15-25mph in the actual circulator, required yield for
approaching traffic to the traffic in the circulator, and to choke the
speed down at the approach by a significant deviation in direction at
the entrance.
The safety research done to date (summarized in 1999) indicates that
roundabouts are much safer for motorists, somewhat safer for
pedestrians, and a wash to somewhat safer for cyclists. Design for
cyclists has improved since the study review I read, due in part to
the recommendations found here:

Roundabouts: An Informational Guide
FHWA-RD-00-67, June 2000
http://www.tfhrc.gov/safety/00068.htm

A 1999 review of existing practice in the United States by the TRB may
be found here:
http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp_syn_264.pdf

Excerpts concerning cyclist safety information (comparing before-and
after-roundabout construction)
From Germany:
For bicyclists the results were mixed, depending on the bicycle
arrangement. Bicycle lanes at the outer edge of the circulating
roadway were found to lead to more accidents (increase from 1
to 8 accidents). No significant safety impacts were found when
bicycles mixed with regular traffic or with the pedestrian path,
or when bike paths were built outside the circulating roadway.

France (existing roundabouts, 1988 review, doesn't compare the
accident rates before and after construction):
The study found that, although the number of crashes
involving bicycles was lower for roundabouts than for
signalized intersections, the reduction was less than for the
other modes of travel. About half of the bicycle and moped
crashes were due to a refusal of priority of the entering vehicle
vis-a-vis the circulating bicycle, and a large proportion of these
crashes occurred at two-lane entries.

UK: (for existing roundabouts--doesn't compare the accident rates
before and after):

A disaggregation of crashes by road user showed that
bicyclists are involved in 13 to 16 percent of all [injury] accidents,
and
motorcyclists in 30 to 40 percent. The accident involvement
rates (per 100 million of road-user class) of two-wheeler riders
were about 10 to 15 times those of car occupants. Pedestrian
crashes represented about 4 to 6 percent of all crashes at this
sample of roundabouts. [They also don't report the total crash rate,
so we can't tell if this is worse, the same, or better than a standard
intersection].

Other than the usual "kick them off the road" reflex traffic engineers
have toward vehicular cyclists (you can smell the disapproval oozing
from the discussion in the document) when discussing traffic safety,
the resulting recommendations found in the 2000 design recommendations
for cyclists have improved roundabout design for us in the United
States.

I know the ones I've encountered here in Colorado (Vail/Avon, CO 52,
Fort Collins) have been well-designed, though motorists are still
figuring the new ones out, and I find the dual roundabout at CO 52/
I-25 a novel experience. The roundabout at Taft Hill on Vine Ave in
Ft. Collins is a textbook example of a single-lane rural modern
roundabout, and to date, it has functioned well in my experience. I
sure prefer it to the old 4-way stop there, where I had a couple of
near-misses when folks roared right through the intersection at
50+mph. On the other hand, the curb-stop mini-roundabouts installed
as traffic calming devices in Boulder's neighborhoods weren't terribly
well-designed, and haven't done us many favors.

Okay, far enough afield for me. Randonneuring content: The Colorado
400K and 600K ACP brevets traverse the I-25 dual roundabout at CO 52
and the rural roundabout at Taft Hill Road/Vine road.

You should all come out and check their operation out later this
spring!

Disclaimer: I'm a hydraulic engineer by training, not a traffic
engineer. My firm has designed modern roundabouts in WI and FL that
have been well-accepted. I wasn't involved in the effort, and my
office doesn't do roadway design.

Best Regards,

Will

William M. deRosset
RUSA 2401

[John Lee Ellis]

Fascinating indeed - thank you, Will. As for the dual roundabouts to
which Will refers, they are lots of fun on the 400k and 600k, as we
hit them at daybreak when there is very little traffic anyway. BTW,
for motorists, these dual roundabouts have immensely improved the
situation.

There is also a roundabout in Nederland on the Peak-to-Peak 300k.
It's smallish, but traffic is moving slowly (especially in winter, as
they are bound for the ski resort).

The "calming" ones in Boulder are as Will describes - "perturbing"
would be a better word. (On a "don't get me going" note, many
"calming" devices, such as the curbed constrictions, medians, etc. in
Golden, imperil or at least inconvenience cyclists, since they must
merge into traffic, and traffic must wait for them.)

-john lee

On Feb 6, 10:55 am, WMdeR <wmderos...@gmail.com> wrote:
> Dear All,
>
> (Long, opinionated post, only tangentially related to randonneuring,
> but isn't traffic engineering cool and dear to all our hearts?).
>
> I prefer the "modern" roundabout.  Rotaries and traffic circles are
> different things.  Roundabouts are designed to have maximum safe
> speeds of 15-25mph in the actual circulator, required yield for
> approaching traffic to the traffic in the circulator, and to choke the
> speed down at the approach by a significant deviation in direction at
> the entrance.
> The safety research done to date (summarized in 1999) indicates that
> roundabouts are much safer for motorists, somewhat safer for
> pedestrians, and a wash to somewhat safer for cyclists.  Design for
> cyclists has improved since the study review I read, due in part to
> the recommendations found here:
>
> Roundabouts: An Informational Guide

> FHWA-RD-00-67, June 2000http://www.tfhrc.gov/safety/00068.htm

> > - Bruce- Hide quoted text -
>
> - Show quoted text -

[Bob Cooper RUSA 937]

The thing which is now called the modern roundabout has just begun to
appear in my area, Western New York.

As traffic approaches the circle, it is choked down to a narrow lane,
and the circle itself is so small that car tires begin to squeal at
about the speed that a fast cyclist could take the circle.

These are single-lane roundabouts, not the big "traffic circles" that
we still have left over from decades ago.

They are supposed to be less expensive to build and maintain than a
set of traffic lights, so I think they are here to stay.

Bob

[Steve Palincsar]

I hope so. They do a wonderful job of traffic calming, and make it very
easy to cycle through such intersections -- at least, based on my small
sample. What's more, the drivers don't seem to mind.