Legal Definitions - casus improvisus

Casus improvisus is a Latin legal term that refers to an unforeseen case or a situation that was not specifically provided for by an existing law, contract, or set of rules. It describes a scenario that was not anticipated or contemplated when the legal framework or agreement was originally created, and therefore falls outside its explicit scope.

When a situation is deemed a casus improvisus, it means that the existing provisions may not directly apply, or there might be a gap in the rules regarding how to handle it. This often necessitates a new interpretation, an amendment to the existing rules, or the creation of new guidelines to address the previously unconsidered circumstance.

• Example 1: Unforeseen Technological Advancement

  A city ordinance from the 1980s regulates "motorized vehicles" on public walking trails, primarily intending to prohibit cars and motorcycles. Decades later, electric bicycles and personal mobility devices like motorized scooters become widely popular. A person riding an electric bicycle on a trail is cited under the old ordinance. The rider might argue that the electric bicycle is a casus improvisus because it is a new form of transportation not contemplated when the original ordinance was drafted, and it operates differently from the traditional "motorized vehicles" the law intended to ban. The city would then need to decide if the old law applies, or if a new regulation is required for these modern devices.

• Example 2: Unexpected Event in a Contract

  A contract between a software development company and a client specifies deadlines and penalties for delays, with clauses for "force majeure" events like natural disasters or war. However, during the project, a global cyberattack on a critical internet infrastructure provider causes widespread outages, making it impossible for the development team to access necessary cloud services for several days. This specific type of disruption was not listed in the contract's force majeure clause. The cyberattack could be considered a casus improvisus because it was an unforeseen event not explicitly covered by the contract's provisions for excusable delays, requiring the parties to negotiate how to address the impact on the project timeline.

• Example 3: Novel Employee Situation

  A company's employee handbook outlines policies for various types of leave, including sick leave, vacation, and parental leave. A long-term employee, however, requests an extended leave of absence to serve as a bone marrow donor for an unrelated patient, a procedure requiring significant recovery time. The handbook does not contain any specific provisions for "organ donation leave" or similar medical procedures not directly related to the employee's own illness or family care. This unique request represents a casus improvisus, as it falls outside the established categories for leave, prompting the company to develop a new policy or make an ad-hoc decision for this unaddressed scenario.