Dual Ped Ramps

[arizonadude]

I am bringing an existing intersection up to current standards. I am placing two pedestian curb access ramps at each corner. The client has asked that I place the ramps as to abutt eachother in order to shift the sight triangle. I have searched the MUTCD to locate minimal dual ramp placemen, but cant find anything. any info would help, thank you.

 

[ACtrafficengr]

You won't find it in the MUTCD, since curb ramps aren't a traffic control device.

Try here for guidance:

http://www.access-board.gov/prowac/alterations/guide.htm

And here for the proposed regulations:

http://www.access-board.gov/prowac/nprm.htm

 

[cieg22]

Our DOT recommend a min 2" curb reveal between the ramps (where the flares would meet). The also note that rapidly undulating grades could be uncomfortable to pedestrians.

I've heard horror stories about not-so-well-informed reviewers (not in my area, thank goodness!) taking issue with a shared landing - on the outside chance that two pedestrians in wheelchairs may try to simultaneously cross the intersecting streets, head up the curb ramps and need use of that landing at the exact same moment. If I ever see that happen, I will certainly play the lottery that day. Joking aside, you may want to triple check your local standards and practices.

 

[daOwenator]

I'm in PA, but typically we try to follow our DOT standards for all ADA ramps. In PA, I don't believe that there is a min. length for a ramp, thus the minimum length of a ramp would be the 2' width of the DWS itself. Typically I would want the ramp to be at least 4 feet long, though that's my preference, not a requirement. The length of your ramp will typically be governed by how much elevation change you have. The length of your ramps will then tell you how far apart 2 ramps on the same corner will need to be. When I layout ramps, I usually begin at the gutterline elevation of the lowest ramp (gutterline elevation on side nearest the intersection), then I work up at a max of 7.5% to my shared landing, then I go max 7.5% down the other ramp to its gutterline. All other grades are determined based on these grades. If less severe grades are possible, then use less severe grades!

 

[IRstuff]

Almost all of our local streets use a shared ramp:

http://maps.google.com/maps/place?f...&ved=0CA4Q-gswAA&sa=X&ei=zrVgUN7zKeTXxQGA9oAQ

TTFN
faq731-376

 

[Debaser]

IRstuff
I've got to say, to my (Brit) eyes, they look like odd crossing details.
The solid road markings, presumably meant to delineate the crossings, actually take peds to full height kerbs and the dropped area is in a sort of no-man's land between each crossing, and if that wasn't enough, they (the solid lines) tend to channelise you towards pieces of street furniture, i.e. the signal poles in the footway.

We would tend to put in tactile paving (in this case red for a signalised junction, or otherwise buff if uncontrolled) and site the two crossings such that the blisters on the tactile paviours directed (partially sighted) peds in the direction of the opposite footway. The crossing areas to be kept as free of street furniture as is possible.

If we were to do something similar over here then the dropped area would extend all the way round the radius, to the outermost solid white lines delineating the crossing.

 

[ACtrafficengr]

Debaser, I like the idea of color-coding the tactile surface. Do walkers generally know what it means?

I don't think we'd be allowed to use buff with a concrete sidewalk - it must either have high contrast with the sidewalk, or be high-visibility yellow. Most places near me use brick red or dark grey.

 

[IRstuff]

On the same map above, if you scroll southeast down Imperial to here:

http://maps.google.com/maps/place?f...&ved=0CA4Q-gswAA&sa=X&ei=zrVgUN7zKeTXxQGA9oAQ

you can see that there are what I'd call traction patches embedded in the center of the ramps on all the corners but the northeast one. The black of the traction patch provides visual contrast, and provides additional traction on the rare days when it rains in Southern California.



TTFN
faq731-376

 

[Debaser]

ACtrafficengr
Because we tend to use bituminous surfaces/asphalt rather than concrete for our footways and carriageways the buff tends to stand out much more. Depending on the Local Authority we might also use a soldier course of block paving around the tactiles to give an additional contrast. However, since I believe only a very small number of those registered blind are completely sightless, and most other visually impaired people have some degree of vision (albeit poor) then most pedestrians can make out the contrasting colours. In addition, at signalised controlled crossings (which includes zebras) we use an 'L' arrangement, with the 'tail' stretching to the back of the footway, and on the side of the crossing with the push button unit.

http://assets.dft.gov.uk/publicatio...-tactile-paving-surfaces/tactile-pavement.pdf

This is the publication we work to. Although it is called guidance it is accepted as the de facto standard. I am slightly sceptical about some of the tactile arrangements at uncontrolled crossings, which suggest that sightless peds can differentiate between the number of blocks wide or deep a crossing is by feel, to tell them where they are in relation to mid-block or in-line crossings, but they are what is advised and have been researched, along with blister height, etc.