Making the Connection Between Access Guidelines and Reality: A Case Study of Curb Ramp Design and Construction from San Francisco, California

by Tom Rickert for Adaptive Environments’ National Pedestrian Design Project for Project ACTION

(This case study is based on interviews on April 24, 2006, with Kevin W. Jensen, Disability Access Coordinator for the San Francisco Department of Public Works, and Eduardo Pestana, an Engineer with the San Francisco DPW Streets and Highways Section)

San Francisco is an old city by American standards, with the majority of its 30,000 street corners laid out decades prior to the passage of the ADA. Curb ramp location was not a consideration when most of the city’s curb returns were constructed. Sidewalk widths vary and underground utility boxes and vaults under many street corners even vie for space in a few neighborhoods with residential basements which extend out to the curb line. Poles for street lights, fire alarms, electric trolleys, light rail lines, and a variety of other purposes exist alongside street furniture, bike racks, mail boxes, etc. Drainage issues require gutters and catch basins and storm sewers to carry off heavy winter rains. Street trees, often planted in decades past without regard for ADA standards, may also impede access. Some streets have excessive crowns of up to 12%. While much of the city is laid out with a grid of streets, the many hills and other features result in hundreds of intersections which are at every conceivable angle – charming at times for tourists, not so charming for city engineers trying to build curb ramps. Adding to the confusion, San Francisco was off to an early start in its attempts to build curb ramps, well before current best practices were a factor. The resulting “non-complying” curb ramps, while a tribute to early efforts beginning in the 1970’s, result in thousands of older curb ramps needing to eventually be upgraded.

Photo above: Kevin Jensen, the Disability Access Coordinator for San Francisco’s Department of Public Works.

Kevin Jensen, the Disability Access Coordinator for San Francisco’s Department of Public Works has the unenviable job, in his words, of “dealing with the real world of fitting curb ramps in with all this existing infrastructure.” In San Francisco, “there is no such thing as a standard curb ramp. Each one is unique,” observes Jensen.

The ADAAG regulations and the California Building Code are the main federal and state norms which must be followed by San Francisco, with the State Building Code sometimes providing more rigorous standards (e.g., requiring wider sidewalks and curb ramps than does ADAAG). Neither is viewed as a model of best practice. The FHWA’s Designing Sidewalks and Trails for Access (Part 2, Best Practice Design Guidelines) is a highly respected resource for San Francisco curb ramp planners.

DPW has its own in-house standards, updated four years ago by its staff with input from engineers with its Streets and Highways section and DPW sidewalk inspectors. The results of a citywide curb ramp survey conducted in 2000 were also taken into consideration. The result is a set of in-house standards which go beyond the requirements of ADAAG and the California Building Code while also addressing the exceptional situations which turn out to be the norm in San Francisco. This is done through a series of drawings, starting with a “standard curb ramp plan” with a “typical normal layout” and then continuing with alternative designs based on different locations of catch basins, different street corner and sidewalk geometries, and constrained spaces which require merging of the grooved borders of pairs of curb ramps or even merging of the flared sides of pairs of ramps along with different space constraints due to narrow sidewalks and a variety of other conditions. Drawings include ramps for landscaped pathways with no curbs and for passages through street medians and mid-island bus and rail platforms.

The Dept. of Public Works uses a curb ramp priority matrix to help schedule work. Citizen requests are prioritized, followed by locations serving public offices and facilities, transportation-related locations, and locations serving places of public accommodation. Priority is also given to replacing older non-conforming curb ramps which present safety concerns, followed by the provision of new curb ramps where none currently exist. (Roughly 25,000 curb ramps are now in place.) While theoretically each street corner would require two ramps (that is, eight for a full intersection), in the real world in turns out that an average of 1.7 ramps per street corner are required.

The process of assuring that access guidelines turn into good curb ramps on San Francisco’s street corners differs according to whether construction is done in-house by DPW staff or is done by developers via a permit approval process.

1. Construction In House by DPW

Photo above: Eduardo Pestana of DPW, at left, and Kevin Jensen inspect a curb ramp design.

Once curb ramp sites are prioritized and funding is obtained, building a new curb ramp (or a replacement curb ramp) currently involves four site visits by the DPW engineer charged with designing the ramp to fit its specific location. Actual construction is currently performed by three work crews, each comprised of three city employees (one of whom is designated the team leader for each crew). These nine crew members report to a single foreman.

The process is as follows:

1. One of the four DPW engineers who design curb ramps visits the site to map the curb return, adjacent property lines, underground utilities, street furniture of every kind, and grades. Grades are tracked to adjoining areas beyond the curb return if this is appropriate.
2. Using standard AUTOCAD software, data points are inputted and a computerized ramp design is created. The many non-standard situations require approval by the Disability Access Coordinator prior to forwarding the design to the foreman of the three work crews.
3. The engineer who performed the design work visits the site and paints the saw cuts to assure compliance with the design.
4. A demolition crew performs the saw cuts and demolition work (also reporting any unforeseen obstacles).
5. A second crew constructs the forms for the concrete pour, using the design drawing.
6. The engineer in charge of the design visits the site to check the forms prior to the pour, using a laser device to “shoot the elevations.” (It is hoped that the crews can themselves take over this responsibility in the future.)
7. The concrete is poured.
8. The engineer in charge of the design makes a final inspection to assure that the curb ramp is acceptable.

Photo above: Inspecting data points of an AUTOCAD curb ramp design.

This process is expensive due to San Francisco’s old infrastructure where “exceptions are the rule” when it comes to curb ramps. One third of curb ramp cost goes for design and two-thirds for actual construction. Construction costs also include the placement of a tactile warning strip aligned with the curb ramp on the opposite corner. Curb ramps constructed under simple conditions are of course far less expensive than curb ramps requiring the relocation of utility boxes or street furniture.

Jensen also stresses the need for making sure that employees are well motivated. “Curb ramp work is valued work in San Francisco,” he notes. The engineering staff needs to be valued and motivated, as well as the construction crews. “When someone chooses access work, it needs to be seen as a positive part of their resume in terms of their work history. For example, by creating specialist team leader positions amongst civil engineers, with authority that goes with it, there is an opportunity to demonstrate their capabilities for advancement.” The same goes for the work crews. Retrofitting existing city infrastructure takes funds and it takes skill. Work crews “need to really know their stuff...to do a curb ramp in San Francisco.”

2. Construction of Curb Ramps by Developers

New developments in San Francisco normally require the construction of new sidewalks and curb ramps paid for by the developer using the developer’s contractors. DPW controls curb ramp quality by issuing the necessary permits for the project. Project plans are reviewed by the Disability Access Coordinator and inspections by DPW’s Bureau of Street Use and Mapping during construction assure compliance. Jensen stresses the need to meet personally with the developer and the developer’s contractors. He notes, “If we just throw our standards at a contractor, most likely the curb ramps won’t come out that well...It is a tough thing to get high quality work using people with less expertise (i.e., than city staff working full-time on curb ramps). It is more challenging to get a quality product in the end.” On the other hand, curb ramps along new sidewalks, built as part of a large development with new infrastructure, may lend themselves to more standard design and usually cost less than curb ramps built in the more constrained situations often faced by DPW staff as they deal with decades-old infrastructure.

Summing up, San Francisco “bites the bullet” when it comes to assuring quality curb ramps.  Curb ramps are individually designed to fit each situation so that quality and accessibility are maintained as well as possible in the face of daunting constraints caused by a multitude of situations never envisioned by ADAAG or the California Building Code. The person who does the design inspects the work of the construction team at critical points. Professional staff and work crews keep in touch and are proud of their work. They are motivated to do a good job.

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