Tag: sidewalk

the problem with rolled curbs

Dan Allison1 Comment

Curb&GutterDiagramsRolled curbs slope up from the gutter pan to the sidewalk, whereas standard curbs have a more vertical face. Standard curbs are both old and modern, but there was a period of time in the 1950s through 1970s when rolled curbs were very popular, seen as a sign of the new suburbs. In the grid area of Sacramento, including the first ring suburbs, standard curbs are quite common. In the second ring suburbs and the sprawl suburbs, rolled curbs are quite common, not only being found in residential neighborhoods but even on arterial roads.

parking up on the sidewalk with rolled curb
parking up on the sidewalk with rolled curb

So, what’s the problem with rolled curbs? Drivers use rolled curbs to drive up on the edge of the sidewalk, constraining the sidewalk width, reducing walkability, and not infrequently causing blockage of the sidewalk for people in wheelchairs. ADA regulations require at least 36 inches of clear width. Combine the narrow 4-foot sidewalks that were popular in the suburbs with this driver behavior, and the car-influence zone is expanded to the complete width of the right of way, leaving no place for pedestrians. [Note: This photo is for illustration purposes only, not to give this driver a hard time. This is common practice, and I’ve seen many instances where much more of the sidewalk was blocked.]

A side affect of parking up on sidewalks is that it leaves more of the street width for moving motor vehicles, which then increases the speed at which people drive. By trying to get their vehicles out of the way of the “speeding drivers,” they are actually making it easier for drivers to speed.

What are the solutions?

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whose responsibility are sidewalks?

Dan Allison8 Comments
broken sidewalk, Sutterville Road at 24th Street
broken sidewalk, Sutterville Road at 24th Street

Note: As I wrote this post, I realized that some background info was needed, hence two related posts: sidewalk buffers and surprisingly good sidewalks.

This week an article in the Sacramento Business Journal, “Rancho Cordova wants to make sidewalks problem of property owners,” talked about the city’s efforts to shift responsibility for sidewalks to the property owners, both residential and commercial. The city spokesperson, Davis Gassaway, attempts to gloss over the impact by saying that it should only cost $1000-1500 to repair a sidewalk, and that Sacramento, Roseville, and West Sacramento already have such ordinances. I think the costs quoted are on the low side. At about $4 per square foot (significantly more for curbs), $1000 would buy 50 linear feet of five foot wide sidewalk in a residential area, and 25 linear feet of ten foot wide sidewalk in a commercial/mixed use area. And just because another city is doing it doesn’t make it a good idea. So, what’s wrong with the idea?

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sidewalk buffers

Dan Allison2 Comments
garden sidewalk buffer on Q Street
garden sidewalk buffer on Q Street

The purpose of sidewalk buffers, also called planting strips, is to isolate pedestrians from moving motor vehicles, where parking does not provide a sufficient buffer. Sidewalks adjacent to the curb are called attached sidewalks, while sidewalks with a buffer are called detached sidewalks.

Traditionally all residential, collector, and arterial streets had buffers. Retail areas often did not, in order to make getting from the car to the sidewalk more convenient.

Modern suburbs, however, usually eliminated the buffer strip from all streets in order to maximize the area available for development and roadways. Pedestrians do not like to walk next to fast traffic. In part, the elimination of buffers is why there is much less walking in the suburbs. The lack of buffers also makes an area look harsh, with a bland expanse of pavement rather than the welcoming and beautiful strip of nature. The planting strips and their vegetation require maintenance, and responsibility for those areas is another question of responsibility.

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what to do with recovered street width

Dan Allison1 Comment

When 3-lane streets are narrowed to 2-lane streets, street width is recovered for other uses. Traffic lanes are commonly 12 feet wide, though they can be as narrow as 9 feet and as wide as 14 feet or more. Most streets in the downtown/midtown area that I’ve recommended for narrowing are really five lanes wide, three traffic lanes plus two parking lanes. Eight ways in which this recovered right-of-way width can be used:

  1. Widen sidewalks: In some areas, sidewalks are too narrow to carry the number of walkers using them. For example, on 16th Street between P Street and O Street, the sidewalk is much too narrow to handle the foot traffic. There are six businesses on the east side of the street: Pronto by Paesano’s and the associated Uncle Vito’s Pizza, Super Cuts, Nishki Sushi, and Starbucks, plus a storefront that is being refurbished to be Thai Canteen. These generate a lot of customers on foot and on bike, and the narrow sidewalk is frequently crowded.
  2. Add sidewalk buffers: In cases where the sidewalk is immediately adjacent to the street, or a there is a buffer but it is too narrow, width can be devoted to these buffers. Sidewalks with buffers are called detached sidewalks. These may not appropriate in commercial areas because the isolated high-turnover parking from the sidewalk, but are completely appropriate in residential areas and may be in mixed areas.
  3. Add bicycle lanes: Bicycle lanes take up five feet of width if adjacent to the curb, and six feet if adjacent to parking. (AASHTO standards are a minimum of four and five, but these widths are unsafe.) Normally a street will have bike lanes on both side, so two bike lanes will take about the same space as one traffic lane. If we were to otherwise leave the street system as it is, with high speed one-way streets, the protection of bike lanes is critical to making downtown/midtown more bikeable. However, if the recommendations I have made were implemented, streets would move more slowly with lower volumes of traffic, and bike lanes would be less necessary.
  4. Add protected bike lanes: A protected bike lane (cycle track) is a protected bike way, with some sort of physical protection from motor vehicle traffic. The protection can be a painted no-vehicle area, hit posts, curbs, parked cars, or a surface raised to a level between the roadway and the sidewalk. Because the protection takes up space, in many situations only a single protected bike lane can be gained from the removal on one traffic lane.
  5. Add dedicated transit lanes: Bus routes on streets with heavy traffic are often slowed by congestion and by turning vehicles. Both bus and light rail can be sped up by removing some of the conflict with dedicated transit lanes. Long distance dedicated lanes can be used to create bus rapid transit routes, but short segments of lanes can be useful for solving spot congestion problems. If light rail and buses run more freely, transit times are reduced and people will be more likely to choose transit over privately owned vehicles. It is not clear to me at the moment whether any of the 3-lane streets are logical locations for dedicated transit lanes, but I will look at this in the future.
  6. Create wide medians: Medians can be created along the middle of the street, separating the two travel directions. These medians can have plantings, artwork, rainwater basins, sitting areas, and a number of other amenities that may be absent along the street. These parkways or boulevards are probably not appropriate in commercial areas, but would be in residential or mixed areas.
  7. Convert from parallel to diagonal parking: Conversion from parallel parking to diagonal parking (60 degree reverse angled parking) uses up about 8 feet of street width, and roughly doubles the amount of parking. Because parking takes more of the street width, it is even more important to consider curb extensions (bulbouts) to increase pedestrian – driver visibility at intersections and mid-block crossings.
  8. Create center turn lanes: If the street is also being converted from one-way to two-way, the center lane can become a turn lane. I think that this is the least useful of the solutions because it serves a single and not very common need, left turns, with an entire dedicated lane. If the traffic on a street is so heavy that it is difficult to make left turns, a left turn pocket or a block-long center turn lane can be provided every four to eight blocks, but having a continuous lane is just a waste of precious right-of-way.

Certainly not every solution is right for every situation, and each roadway segment should be analyzed to determine the best overall use of the width recovered from 3-lane to 2-lane conversion.