Category: Street Design Standards

NACTO yield street

Dan Allison4 Comments

NACTO (National Association of City Transportation Officials) is the lead organization for progressive transportation cities. It is in strong contrast to regressive organizations such as League of California Cities which exist primarily to serve suburban areas. Of course part of the difference is the size of the cities, as NACTO tends to include large cities, while League of California Cites tends to include small cities, but it is really a difference in attitude about what cities are for. NACTO cities are cities for people, League cities are cities for cars and businesses. Take a look at CalCities Partners to see who the League likes. Unfortunately, City of Sacramento is a member. But on the plus side, Sacramento is also a member of NACTO.

In upcoming posts about Street Design Standards, I will be using NACTO materials often, primarily from the Urban Street Design Guide, but from the Transit Streets Design Guide and Urban Bikeways Design Guide as well.

I believe that the Street Design Standards should include both overviews of different kinds of streets, to provide city staff, city council, and most importantly, the public, a clear picture of what a new or reconstructed street will look like and feel like. Design details are also important, but design details without context just allow staff to build streets that follow the rules but neglect safety and livability.

So, first up, the overall design that NACTO calls a Yield Street. The portion of the street devoted to moving motor vehicles is less than most of the streets in Sacramento, but the portion devoted to street-related uses is more. The most prominent difference is that the travel part of the street is not two lanes, but a shared area (hence, the yield name) where drivers must negotiate to pass and adjust for variable widths as parking and other uses vary. This is easily a street for a 20 mph design and posted speed limit, as all local streets should be. Note also: wide planting strips with trees, perpendicular ADA ramps, high visibility crosswalks, curb extensions on most corners, small corner radii, pedestrian scaled lighting, and reduced but not eliminated parking. The diagram shows just residential uses, but the design can easily accommodate corner stores.

NACTO Yield Street diagram
NACTO Yield Street diagram
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SacCity street design ideas

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I have decided to start a series on street design ideas and standards, as a support for the City of Sacramento update of its Street Design Standards, due to occur this calendar year. I would hope that the city would actually engage citizens and transportation experts in the development of the standards, though it is more likely that the city will present a late-draft-stage document for review. In either case, I hope to educate the public about what good street design looks like and functions like, so that they can provide useful input and demand the highest level of design safety and innovation from the city.

The posts will be available under the category ‘Street Design Standards‘. Though this is a subcategory of City of Sacramento, the posts will almost entirely be applicable to any city or county.

First up, existing design standards and concepts. The horrible state of our transportation system is due in large part to the practice of traffic engineers using highway design ideas on urban streets. These designs have encouraged traffic violence, reduced the livability and economic vitality of cities, and created infrastructure that we will never have the funds to properly maintain. And, most importantly, then have killed millions of people and maimed at hundreds of millions more.

If you have not read it yet, I can’t more highly recommend Confessions of a Recovering Engineer by Chuck Marohn, founder of Strong Towns, for a review of the traffic engineering malfeasance and embedded but never explicit values that got us to this point.

There are a number of existing publications and resources for designing streets, some of them useful, and some us them which got us into this mess to begin with. Here are the ones I recommend that the city use, and not use:

SacCity street design standards

Dan Allison2 Comments

I had recently posted on the design for alley sidewalk crossings, based on a document from the City of Sacramento website. I shortly thereafter discovered that there are at least two sets of standards. The Department of Utilities, on the Development Standards page, has a Standard Specifications document which includes some text about streets, and the Transportation appendix of standard drawings which contains the diagram referenced. If you look at the text document, you will notice that it does not link itself to the Department of Utilities. Who wrote it, who would you contact about it? Who knows. Why the Department of Utilities has its own designs, separate from Department of Public Works, which has assigned responsibility for transportation, isn’t clear at all. On the positive side, though, this document was updated November 2020.

The Department of Public Works has its own Section 15 – Street Design Standards, part of the Design and Procedures Manual, linked on the Public Works Publications page. This is the document I discovered after using the Department of Utilities document. On the negative side, this document was last updated in June of 2009. Fourteen years ago. Again, there is no attribution to department in the body of the document. I only know/think this is a Public Works document because it is linked from a PW page.

There have been immense changes in street design best practices in that time. Most of the diagrams are overviews of arterial and collector roadways, very little about other streets. Bike lanes of any sort? Nada. ADA ramp details? Nada. Protected intersections? Nada. Curb extensions (bulb-outs)? Nada. Traffic calming infrastructure? Nada. The text of the document does contain references to a few of these issues, but without corresponding diagrams, there really is no guidance at all.

In searching for design diagrams, it appears there are additional designs scattered across the city website, some of them having to do with subdivisions, which seem to be treated separately from other street design. Let me say that this is not at all clear. The city website contains many documents without attribution to the department which created it. The city search engine is one of the poorest I’ve ever seen, and when it finds a document, it is almost impossible to tell where it came from or on which webpage one might find it.

At the SacATC (City of Sacramento Active Transportation Commission) meeting on 2023-03-16, staff presented an Introduction to Current Active Transportation Efforts. Under Projects, item 6 is ‘Street Design Standards Update: website expected in Fall 2023’. I spoke at the meeting about the weakness and antiquity of the current standards, and about the confusion over which set of standards is being talked about. City code, in Title 17 Planning and Development Code also has references to street design, but no linkage to the corresponding street design documents or diagrams. I don’t think staff realized how big a mess this is. It is not just the Public Works document that needs to be updated, but all city references to street design pulled together and properly referenced and linked.

A post in the near future will provide my ideas about what a street design manual ought to look like.

cover page of Section 15 - Street Design Standards, of the Public Works Design and Procedures Manual

sidewalks across alleys

Dan Allison4 Comments

Note: Please see post on City of Sacramento Street Design Standards. It turns out that there are at least two different sets of design standards.

The City of Sacramento has Standard Specifications and Drawings that require certain designs for the public right-of-way. There were last revised April 2020, and are available on the Utilities: Development Standards page. It is not clear why these are part of Utilities rather than Public Works or Community Development, but they are. Though I haven’t done an element by element comparison, they seem to be a considerable improvement over the previous standards, which seem to be June 2009.

There are designs which are not being followed, and others that should be eliminated. Today, I’ll address sidewalks crossing alleys. Alleys are only common in the central city, but they do exist other places throughout the city.

The city design standard is below (pdf of entire page). The detail is hard to see, but the alleyway, sidewalk, and alley driveway are all concrete, none are asphalt. The T-11 Standard Alley Entrance Detail page says “Portland Cement Concrete (PCC) is the city standard pavement for alleys.”

SacCity Specification detail alley entrance

Of course there are many alleyways that are asphalt, and some that are unpaved gravel. I don’t know when the city standards changed to require pavement, or when to require concrete, but those are the current standards. That means that if an alley, or a sidewalk, or the alley driveway is changed, it must meet current standards. Below is a photo of Neighbors Alley at 17th Street, which was just redone within the last two months. It clearly does not meet city standards. Both the driveway and the sidewalk are asphalt, not concrete. Though I noticed this work being done, I failed to notice who was doing it. City? Private? Private utility? Not sure.

photo of Neighbors Alley at 17th Street
Neighbors Alley at 17th Street
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