Part of an ongoing series of posts to support better streets in the City of Sacramento during their 2023 update of Street Design Standards. New standards must be innovative, safe, and equitable, and it will take strong citizen involvement and advocacy to make them so.

This intersection design post follows on to the SacCity intersections of local streets post, addressing intersections of larger streets. See SacCity street classification for detail on types of streets (local, neighborhood, corridor).

The most important point of intersection design is that multi-lane roundabouts have absolutely no benefit for people walking or bicycling, particularly those with vision or mobility limitations. They are no more safe than regular intersections, and some research indicates they are less safe. They are just more motor vehicle infrastructure masquerading as something innovative and safe. If the city were to include a design for multi-lane roundabout, it would be a travesty.

This is also the last of the design detail posts. I realize that the posts have veered off into related issues, and the piecemeal nature of the posts makes it hard to see the overall pattern, so I will try for a summary post in the near future.

Policy

• New or reconstructed intersections of neighborhood streets will generally use protected intersection design
• New or reconstructed intersections of corridor streets will use prote
• New and reconstructed intersections will include curb extensions, raised crosswalks or raised intersections, and/or protected intersection design
• ADA ramps at intersections will always be perpendicular to the roadway, never diagonal
• Daylighting for visibility will be provided at all intersections, through red curbs, curb extensions, or protected intersections; if red curbs alone are used, the offset from intersection should be at least 15 feet
• Roundabouts: single-lane roundabouts will be considered for any reconstructed intersection except local streets; multi-lane roundabouts have no safety benefits and will be prohibited
• Intersection corner radii will be set to ensure slow and safe turning speeds for all motor vehicles; truck and bus routes will never be more than 15 feet
• Safe crosswalks will be provided at no less than every 1/8 mile in all urbanized areas; 30 mph, crosswalks must have at least pedestrian activated or automated flashing beacons; at 40 mph, crosswalks must have full signalization
• Slip lanes will be removed from existing streets and not installed on new or reconstructed streets
• Pedestrian crossing prohibitions will be removed from all intersections except those with freeway onramps and off ramps

Design diagrams will include:

• ADA ramps, including design which prevents accumulation of water at the base of ramps
• intersections of local streets
• intersections of neighborhood streets with neighborhood streets or local streets
• intersections of corridor streets with corridor streets, neighborhood streets, or local streets
• protected intersections
• modal filters/traffic diverters
• single lane roundabouts
• curb extensions (bulb-outs), with concrete curbs
• interim curb extensions with paint/post installations

Two design diagrams for protected intersections, the first from NACTO Don’t Give Up on the Intersection: Protected Intersections, the second from Alta Design+Planning Evolution of the Protected Intersection, for protected intersections, followed by NCHRP Roundabouts: An Informational Guide, for a single-lane roundabout.

Part of an ongoing series of posts to support better streets in the City of Sacramento during their 2023 update of Street Design Standards. New standards must be innovative, safe, and equitable, and it will take strong citizen involvement and advocacy to make them so.

After much thought, and feedback from other transportation advocates, I am finally ready to propose street classifications for the revision of the street design standards. I have written about street classification before: how to classify streets?; NACTO yield street; NACTO neighborhood main street; NACTO downtown streets.

I am offering only three street classifications. I know most classification systems use more, but I’m for simplicity. A key part of this classification scheme is that streets with more than two lanes per direction are NOT streets, and should be called roads instead. Of course they are stroads, but the city is unlikely to use that term. A road is for traveling, and therefore should have few to no driveways and few to no turning movements. Every driveway and ever turning movement is an invitation to conflict and crashes. The arterial roadways in the city fit into the stroad category. We don’t need them, and we should never construct another.

Street classification (see below for diagrams):

• local or yield: narrow lane (unmarked), parking, up to 20 mph; for local travel
• neighborhood: two lanes, regular bike lanes, up to 30 mph; for local and through travel
• corridor: two to four lanes, bus lanes, separated bikeways, up to 40 mph; for local and through travel
• traditional functional classification system (arterial, collector, local) will not be used; classification into residential, commercial, etc will not be used since all areas may be mixed use
• new or reconstructed streets will not be designed for more than two lanes per direction

Policies

• All one-way multiple lane streets should be considered for conversion to two-way streets
• One-way single lane streets will be considered for narrow right-of-ways widths or where right-of-way is needed for other purposes
• Streets which are repaved and re-striped (reallocated) but not reconstructed will include striping that increases safety and reduces speeds
• Reconstructed streets will be designed for the level of VMT (vehicle miles traveled) or  ADT (average daily traffic) that is desired for safety, livability and economic vitality; the design or posted speed limit prior to reconstruction will not control in any way the new design
• Design for reconstructed streets will consider the reduction or consolidation of driveways, and particularly of driveways that are too close to intersections
• Driveway width for single family residences will be no more than 10 foot width; driveways for multi-family and commercial areas will be the minimum required by fire agency
• Center turn lanes will be used only where frequent turning movements into or out of driveways are expected and accepted; they will not be used to fill excess roadway width
• Speed humps or tables on a street generally indicates a failure to design for the desired speed, and will not be used on new or reconstructed streets, and only as a temporary solution on other streets
• When streets are re-striped after repaving, but are not reconstructed, the excess lane width will be devoted to other uses or marked off as invalid travel areas
• Designs will not include dedicated right hand turn lanes, and will not include multiple left hand turn lanes
• Rough pavement surfaces such as brick, cobblestone, or stamped concrete will be considered whenever reduced speeds are desired; however, crosswalks and bike facilities will be smooth
• Rolled curbs will not be used on new or reconstructed streets  
• Streets which are repaved will implement, to the degree possible, the same design as reconstructed streets via right-of-way reallocation and striping

Design diagrams:

• NACTO-like diagrams which show the overall design of each street type
• One-lane, one-way streets
• Woonerfs (shared streets) without curbs and with design elements to ensure speeds of 10 mph or less
• Bioswales for management of storm water

The remaining post in this series will be about intersection of neighborhood streets, and corridor streets. Stay tuned!

Part of an ongoing series of posts to support better streets in the City of Sacramento during their 2023 update of Street Design Standards. New standards must be innovative, safe, and equitable, and it will take strong citizen involvement and advocacy to make them so.

• Street design will recognize that on-street parking may have a traffic calming effect, however, this effect will not preclude the use of existing parking for other purposes, including but not limited to wider sidewalks, bicycle facilities, parklets, street dining, bicycle and shared mobility parking, planting strips or parking lane trees, and transit lanes
• Where current streets with parallel parking have excess width that encourages speeding, one or both sides of the street should be converted to diagonal parking; new diagonal parking will be back-in
• Parking design will offer dedicated loading and delivery zones as needed; and will include time-limited green curb as needed by businesses
• Parking spaces will be sized for normal passenger vehicles; oversized width or length vehicles may be restricted to certain spots or areas which are designed for them
• Parking areas of streets need not be maintained to the same level as travel lanes

Parking Management

• Parking will be managed and priced so as to create about 15% open parking on every block
• Free parking will be eliminated throughout the city; where metered parking is not practical, parking permit fees will be set at a level that recovers the complete expense of parking space installation, maintenance and management

▾ Design diagrams:

• Parallel marked and unmarked spaces
• Diagonal parking (back-in)
• Curb and pavement markings for prohibition (red), loading (white), delivery (yellow), and time limited (green) parking