From: Brian Ray <BRAY@KITTELSON.COM>
Subject: Re: slowing vehicles on approach
NCHRP Report 613: Guidelines for Selection of Speed Reduction on High Speed Facilities provides a comprehensive overview of the segment and intersection relationships and the considerations of speed. The document includes helpful case studies to aid a user in understanding the operational qualities of a particular roadway/intersection context and methods to consider where and how the treatments might be applied to give drivers adequate time to transition from a "segment" environment to an "intersection" environment. Of special note, the document shares that speed itself is often a surrogate for safety and speed itself may not be a safety concern. Helping drivers understand the change in workload and increased risk that comes from increased conflicts at an intersection may be beneficial.
The FHWA conducted a specific range of low cost improvements to reduce speed. These are also noted in the NCHRP Report and can be found separately on the web at: http://www.fhwa.dot.gov/publications/research/safety/08063/08063.pdf
Here is a link to NCHRP Report 613. http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_613.pdf
Each of these documents contain concepts that are applicable at all intersection types; including roundabouts.
Brian
Brian L. Ray, PE
Senior Principal Engineer
Kittelson & Associates, Inc.
Transportation Engineering / Planning
bray@kittelson.com
503.228.5230
(503) 535-7437 (direct)
From: Gene Russell Sr <geno@KSU.EDU>
Subject: slowing vehicles on approach
This was sent to me in an email. Any of you out there know of any ? Any suggestions of comments ? Good research Idea ? gene
Has anyone seen zig-zag Euro-like striping used on high speed approaches to
roundabouts in the U.S.? If not, what design or striping elements have you
seen used here that would help to reduce approach speeds leading to rural
high speed area roundabouts? I've seen the reduced radius reverse curve
design but was hopeful for other new/effective ideas. Maybe this is not an
actual problem but rather an issue of perception?
Eugene R(Gene)Russell Sr.,PE, PhD,
Professor Emeritus of Civil Engineering,
Department of Civil Engineering,
2118 Fiedler Hall
Kansas State University, Manhattan, KS 66506
Ph. 785 539 9422; Fx 785 532 7717;
Cell. 785 410 5231
email. <geno@ksu.edu>
------------------------------
Date: Wed, 27 Feb 2013 15:52:52 -0800
From: Victor Salemann <Vls@DEAINC.COM>
Subject: Re: slowing vehicles on approach
It’s a great research idea. I recently completed an approach speed study of two different "high speed" treatments using extended splitter islands with varying degrees of reduced radius curves. The initial results show the context of the intersection location, treatment of the central island, and length of the extended splitter island appear to have more of an impact than the reduced radius curve design itself.
From: "Walsh, Brian" <WalshB@WSDOT.WA.GOV>
Subject: Re: slowing vehicles on approach
http://themovement.com/2011/03/03/crooked-street-striping-on-purpose-in-hawaii/
The photo within the above website was my interpretation of a "zig zag stripe" referred to in the email from Gene. Be interesting to see on a higher speed roundabout approach and would most likely garner attention however it might be necessary to have some communication plan to share with driver's in that area.
Brian W.
WSDOT
Are these the squiggles? Attached image of streets in
London?
What I realized in my mini tour of London, was that with
10's of thousands of urban intersections, thousands with odd
angles and multiple approaches and other complications,
signals would be almost impossible. Even more confusing than
all the paint, bike boxes, no stopping boxes and many other
markings used to try to help motorists navigate the streets.
I can't imagine adding a mess of poles, wires, mastarms,
heads, stop bars (and all the power) to the image of
"painted RBT in Notting Hill. Guess I need a scanning tour.
Phil - 303-349-9497
phil@pdemos.com
Subject: Re: slowing vehicles on approach
Not sure what you mean by a European-style "zig-zag".
However, we frequently have yellow strips on approaches in
the UK, which give a visual, physical and (sometimes)
audible warning of a roundabout ahead.
In the example below (Street View), you can see the worn
yellow "rumble"
lines. Zooming out (or moving Street View closer tot he
"roundabout" is interesting because the yellow lines have
been removed and replaced simply with a different coloured
surface - and more traffic signals have been added.
https://maps.google.co.uk/?ll=51.603901,-2.925299&spn=0.0007
26,0.002064&t=k&z=20&layer=c&cbll=51.603901,-2.925299&panoid
=pkJYEX-wkFhJfxctd9XCkg&cbp=12,217.25,,0,0
Ian
From: "Dovey, Dan" <Dan.Dovey@KINGCOUNTY.GOV>
Subject: Re: slowing vehicles on approach
Even if it is effective, one concern I would have with squiggle striping is maintainability. A striping truck couldn't manuever through this type of pattern so they would have to be manually applied, just like thermoplastic. That would only increase costs by being more labor-intensive and time consuming for crews. Our striping gets refreshed every year, every six months on busier arterials.
Dan Dovey, PE
Traffic Control, Modern Roundabouts, and Barrier Systems King County Road Services Division, Traffic Engineering
W: 206-263-6144 C: 206-423-0973
From: "Kingsbury, Dwight" <Dwight.Kingsbury@DOT.STATE.FL.US>
Subject: Re: slowing vehicles on approach
Zig-zag markings like those shown in Phil's London photos are used in the UK at signalized (pelican and puffin) pedestrian crossings, at beacon-equipped "zebra" pedestrian crossings, and at signalized crossings for cyclists and equestrians. Their legal meaning is that parking is prohibited in an area bordered by such markings, and overtaking another driver who has stopped at the crossing is prohibited. They serve, incidentally, to make the crossings more conspicuous to approaching drivers.
http://www.direct.gov.uk/prod_consum_dg/groups/dg_digitalassets/@dg/@en/@motor/documents/digitalasset/dg_191935.pdf
Dwight Kingsbury
From: "Batson, Scott" <Scott.Batson@PORTLANDOREGON.GOV>
Subject: Re: slowing vehicles on approach
The 'Optical Speed Bars' remind me of the old concept for marking speed tables. In that case the bars were centered in the lane and increased in width while decreasing in spacing as the motorist approached the speed table.
The intent is to provide an illusion of speeding up, triggering a response from the motorist to slow down.
I'm not convinced it worked. One glance at the speedometer and motorists will learn to ignore the road markings.
- Scott Batson
-----Original Message-----
From: Roundabout Research [mailto:ROUNDABOUTS@LISTSERV.KSU.EDU] On Behalf Of Russ Wenham
Sent: Wednesday, February 27, 2013 7:27 PM
To: ROUNDABOUTS@LISTSERV.KSU.EDU
Subject: Re: slowing vehicles on approach
FHWA recognizes 2 experimental pavement delineation approaches per the following link:
http://safety.fhwa.dot.gov/roadway_dept/horicurves/fhwasa07002/ch7.cfm
Its relatively easy to secure FHWA approval for experimental use of a treatment that they are marketing.
It would be very interesting to see the impact of Optical Speed Bars on approach speeds at a roundabout.
Russ Wenham, PE
Omni-Means
>>> "Walsh, Brian" <WalshB@WSDOT.WA.GOV> 02/27/13 6:13 PM >>>
http://themovement.com/2011/03/03/crooked-street-striping-on-purpose-in-hawaii/
The photo within the above website was my interpretation of a "zig zag stripe" referred to in the email from Gene. Be interesting to see on a higher speed roundabout approach and would most likely garner attention however it might be necessary to have some communication plan to share with driver's in that area.
Brian W.
From: "Batson, Scott" <Scott.Batson@PORTLANDOREGON.GOV>
Subject: Re: slowing vehicles on approach
Rumble strips work well to warn of centerline crossing or roadside departure, however, their application is best suited to high speed roads and unpopulated areas. The noise generated can be unsettling to residents of nearby homes in an urban environment.
- Scott Batson
From: Michael Wallwork <mjwallwork@ME.COM>
Subject: Re: slowing vehicles on approach
This concept is a rehash of various attempts to slow vehicles with optical means and in cases raised strips. In each the result was a failure. The British found stripes on off ramps lasted at best a few weeks. SCDOT found little sucess with raised strips. And let them wear out. When I found them I n a few cases they had no impact on me as it is easy to see what they are. I have observed several installations. Anne most drivers. Did not react, the regular, novices slowed by Varying amounts. Good idea but humans learn very quickly. In my experience concrete is the only truly effective control
Sent from my iPhone
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