Traffic-calming bumpout design

[southern_yank]

I've started using microstation for some in-house design work. I'm working on a road diet for a residential collector which currently acts as a high speed through street between an urban arterial and our downtown. I've designed about 7 or 8 different kinds of bumpouts, but because the neighborhood blocks aren't a traditional grid, some of the turn radii vary greatly and don't fit a standard bumpout design.

Can anyone recommend a design manual for bumpouts? It would be nice to have some templates I can refer to so when I take my designs to our engineers, I can refer to a previously built design - which may give the bumpouts more "clout" in the eyes of our engineers.

[CPSURaf]

by bump outs i am sure you are referring to bulb-outs at intersections to create a narrower road for safer crossing or midblock crossings (assuming the curb comes closer to the travel lanes to narrow the road, essentially the elimination of parking)? Or am i missing something?

[Tranplanner]

ITE's Urban Street Geometric Design Handbook might be useful...I don't think you can get it as a freebie. Their "Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities" is available online as a pdf here: http://www.ite.org/bookstore/RP036.pdf

[mike gurnee]

Road diet? All you need is speed limit signs. A town very familiar to me constructed a four land road, no driveways permitted (except a city facility), then posted the road at 30 mph.

[Wolfman]

Do people not speed where you live Mike?

[wahday]

Ditto Tranplanner. I would start with the ITE handbook. I worked on a Sector Development Plan a few years back and we used the ITE handbook for a number of traffic calming standards.

[mike gurnee]

Do people not speed where you live Mike?

They really don't. It must be one of the Commandments out here. I pass so many fools who go the arbitrary limit (not Greensburg). I thought about traffic calming on Greensburg streets, but there is really little need. Main Street has all the bells and whistles, but no other.

[Wolfman]

Lucky you. I don't think most areas are so lucky though.

[jmello]

Our city traffic engineer likes to overlay turning templates on our traffic calming device designs. This ensures that certain vehicles (transit buses, school buses, trash trucks, etc.) will be able to maneuver through or around the devices without destroying the concrete or asphalt.

[UrbaneSprawler]

A couple of considerations from my point of view:

- If your municipality does routine street sweeping operations, verify the minimum radius needed to ensure that street sweepers are able to get at the entire curb and gutter section. Angle points to create the bump-outs create areas that can't be street swept. We look to a minimum 15' radius.

- In creating the bump-outs, are you looking to keep drainage along the typical curb and gutter section via a chase, or convey the drainage around the bump-outs?

[ColoGI]

Originally posted by UrbaneSprawler

A couple of considerations from my point of view:

- If your municipality does routine street sweeping operations, verify the minimum radius needed to ensure that street sweepers are able to get at the entire curb and gutter section. Angle points to create the bump-outs create areas that can't be street swept. We look to a minimum 15' radius.

- In creating the bump-outs, are you looking to keep drainage along the typical curb and gutter section via a chase, or convey the drainage around the bump-outs?

I second Tranplanner's 2 recommendations, as well as expanding on fellow Coloradan Sprawler's point about sweeping and snow removal geometries - that is: you must let the staff and private plowers clearly know where the neckdown-bumpout-chicanes are.

I also caution about retrofits - if you are going to put vegetation in there (and why not?!) then you need to do something with the soil underneath that satisfies the plants and the engineers looking for adequate sub-base.

[ssnyderjr]

In the Midwest, or anywhere else that gets snow bumpouts are a constant complaint of the snow plow drivers, as these are nearly impossible to maneuver a plow truck around and inevitably collect snow in the corners. The inability to plow the corners of these usually this results in a loss of 2 spaces per block "face" in the winter .