Design Immunity

Design Immunity

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Take action to help your agency be smarter about risk management!

ReClaim is an important, data-informed initiative that embodies two concepts: First, developing a deep understanding of the claims that represent the greatest impact to members, including cost, reputation, and disruption. Second, building strategies to reduce these claims in the future.

Although these claims impact members differently, depending on each agency’s size and history, there is one common data point: For the liability program—the one program in which all California JPIA members participate—the top five claims have cost $85M over the last five years, or $17M shared annually by all members of the pool.


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  1.  As a new public works director at my agency, how can I determine if design immunity exists?

    First, determine if the city council has delegated a staff member authorized to grant discretionary design approval, and identify that individual. If this has not occurred, then all design plans and subsequent changes to those plans must have been approved by the city council to achieve design immunity. Once this is known, then begin the task of reviewing plans for signature and date or locating staff reports and council meeting minutes that show approval of projects. These can include everything from adding a street signal, crosswalk, stop sign, or bus stop, to major roadway design and construction.

  2.  Design immunity is not a concept with which I am familiar. Can you explain what it is?

    Government Code Section 830.6 states:

    “Neither a public entity nor a public employee is liable under this chapter for an injury caused by the plan or design of a construction of, or an improvement to, public property where such plan or design has been approved in advance of the construction or improvement by the legislative body of the public entity or by some other body or employee exercising discretionary authority to give such approval or where such plan or design is prepared in conformity with standards previously so approved, if the trial or appellate court determines that there is any substantial evidence upon the basis of which (a) a reasonable public employee could have adopted the plan or design or the standards therefor or (b) a reasonable legislative body or other body or employee could have approved the plan or design or the standards therefor.”

    Thus, a public entity should document: (1) its delegation of power to give discretionary design approvals; (2) the existence of design plans; and (3) the discretionary approval of those plans.

    To prove the defense of design immunity, a public entity must establish three elements: (1) the entity’s discretionary approval of the plan or design prior to construction; (2) a causal relationship between the plan or design and the accident; and (3) reasonableness of the plan or design (Cal. Govt. Code § 830.6.). Failure to prove any of the requisite elements is detrimental to the applicability of the defense.

  3.  Can you explain what “‘Substantial Evidence’ of the Reasonableness of the Design” entails?

    Establishing “substantial evidence” on the “reasonableness” of the design is the issue of greatest importance for securing the design immunity. This means that the evidence used as a basis for approving the design must be evidence that a reasonable employee or public body would rely upon in reaching a decision. The design does not have to be perfect, “state of the art,” or beyond criticism. It need only be “reasonable.” This element is normally established by the employee who prepared or approved the design, or in most cases, by demonstrating that the plan conformed to professional standards of design and safety. In most cases, outside experts are used to establish the reasonableness of the design by demonstrating that it complied with professionally accepted design standards included in the Caltrans Highway Design Manual, or the Manual on Uniform Traffic Control Devices, or professional associations such as the American Association of State Highway and Transportation Officials.

    The court has recognized that in design immunity cases, plaintiff experts will not agree with defendant experts as to the reasonableness of the design. Even if experts disagree on this, the mere fact that a plan was prepared or approved by a professional engineer is “substantial evidence of the reasonableness of the design.” In most cases, the signature of the city engineer or the design engineer will suffice in demonstrating “substantial evidence of the reasonableness of the design.” Establishing the design immunity is a process-specific and document-intensive activity which requires that public entities maintain records of the approval process as well as the original design.

  4.  Can design immunity be maintained when new safety features are added to an intersection or other section of the roadway?

    It is possible to maintain immunity of original plans and add new safety features. Work should be performed by an engineer or engineering firm to review speed surveys, traffic volume, warning signage, intersections, visibility, etc. to substantiate the new improvements.

    If there is a roadway marking inventory from the county that contains crosswalk data for example, such as when they were installed, last inspected, last painted, notating if they were removed, and if so, when can be very helpful for establishing and resurrecting immunity. As-built plans can be used to support the design immunity when changes are made in the original design by way of installation of “add-ins” or deletions. In those instances, the design engineer goes to the job site and compares the original design with the design as-built and notes on the plans any changes from the original design such as the addition of a traffic signal, crosswalk beacon, etc., and signs the as-built drawing, which constitutes an approval of the changed design. Adding a hand drawing and notes on the original plans is also acceptable if it is stamped and signed by the engineer.


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Lessons Learned

  1.  Michael Nguyen v. City

    The plaintiff, a husband and father of two, was walking along the sidewalk on a fairly large main street in the City during the evening hours. As he approached the “T” intersection with a residential street, he began crossing from south to north. While the intersection had stop limit lines and handicap ramps for the residential street, those were set back from the intersection and there was no marked crosswalk. Due to the fact that the location involved two intersecting streets, the loss location would be considered an “unmarked crosswalk,” meaning it is reasonable that people would be routinely crossing there. At that same time, an SUV travelling northbound made a right turn onto the residential street, striking Mr. Nguyen, causing a brain injury. Nguyen and his family members filed suit against the City, claiming a dangerous condition of public property (the offset limit lines and handicap ramps, luring pedestrians further back from the actual intersection, making it harder for them to be seen, especially at night). Historical records regarding the intersection design and approval were unable to be found, therefore any opportunity at a Motion for Summary Judgement was lost. The case was therefore settled for $1,000,000.

  2.  Aguilar v. City

    This case involves a unique twist on the application of design immunity. Plaintiff’s decedent mother (Sanchez), was riding in the rear seat of a vehicle being driven by a friend (Zesatti) at a high rate of speed. As they approached the entrance to a Vons distributing center, a semi truck was making a wide right turn into that location, in part due to construction in the lane closest to the curb. Zesatti tried to pass the semi truck on the right, but didn’t make it, striking the side of the trailer, causing two people in the Zesatti vehicle to die. Aguilar filed against the City, the truck driver and their company, and several construction companies doing work on the #3 lane. An encroachment permit had been requested and issued by the City for the lane closure. Prior to issuing the encroachment permit, the City required an approved Traffic Control Plan (TCP). The TCP was then approved by the County of Los Angeles on the City’s behalf and it was in place, as designed on the date of the incident. Using these facts, defense counsel filed a Motion for Summary Judgement based upon design immunity. While that motion was pending, plaintiff’s counsel dismissed his case against the City for a waiver of costs.

  3.  Jara v. City

    This case involves a vehicle v. bicyclist accident that occurred at the intersection of a main thoroughfare and a residential street. The plaintiff was riding his bike through a marked crosswalk when he was struck by a vehicle traveling in the #1 lane. There was a question as to whether or not the flashing in-pavement lights were working at the time of the accident. Defense counsel obtained copies of the original design plans for the intersection that did not include the in-pavement flashers and used those for the basis of a design immunity defense, arguing that if indeed the flashers were not operative, then the aforementioned plans would accurately depict the design of the intersection. Those plans had been prepared by Willdan & Associates and approved by the City Council. With the summary judgement motion pending, the case was settled for nuisance value, at $20,000.

Relevant Court Cases

  1.  Alvarez v. State of California (1999)

    Rosario Alvarez was severely injured, and her son was killed, when a northbound vehicle veered across the median and struck her southbound vehicle. Alvarez sued the State of California alleging that the lack of a median barrier constituted a dangerous condition on public property. After the trial court granted summary judgment for the state based on design immunity, Alvarez appealed, contending that the state failed to establish discretionary approval of a plan and even if the state did establish initial immunity, changed conditions caused design immunity to be lost. However, the appeals court disagreed, noting that “the signature of the various Caltrans engineers affixed in their official capacity as employees of the state furnished ‘evidence sufficient to sustain a finding’ that the writings were what the state claimed them to be. Thus, the plans themselves provide evidence that the project design was given the requisite discretionary approval prior to construction.” Additionally, Alvarez failed to present substantial evidence of changed physical conditions, which would have eliminated the design immunity defense.

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  2.  Grenier v. City of Irwindale (1997)

    In rainy, somewhat flooded conditions, a car jumped the curb and hit a wheelbarrow, injuring Arthur Grenier, who had been working on nearby private property. Grenier brought action against the city, alleging the city negligently designed the drainage facilities for Buena Vista Street “in such a manner that when there was rainfall in the general area, the roadway where the accident occurred would flood” and failed to warn that the flooding created a hidden hazard or trap. When the city was unable to prove that the design feature that made the roadway dangerous was included in the plan or design on which the design immunity was based, the court ruled in favor of the plaintiff, holding that “design immunity does not immunize decisions which were not made.”

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  3.  Rodriguez v. Department of Transportation (2018)

    Erik Rodriguez was a passenger in a pickup truck that ran off the road and into a drainage ditch. He sued the Department of Transportation (Caltrans) for maintaining an allegedly dangerous condition of public property, alleging the edge of the roadway did not contain warning features, such as a “rumble strip,” that would alert a driver who inadvertently veered onto the shoulder. When the Caltrans engineer who approved the design testified that he did not consider whether “rumble strips” should be part of the design or include them in the design which he prepared and approved, Rodriguez argued that the design lacked the required “discretionary approval” necessary to establish design immunity. The court disagreed and granted summary judgment in Caltrans’s favor, holding that it is not necessary to prove how a decision was made in order to approve the design or demonstrate a conscious weighing of design or plan options and alternatives.

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California JPIA