Engineering & Risk Assessment
By: Ronald J. Cohen, P.E.
Whether you represent a plaintiff or defendant in a case, the question remains whether the conditions or circumstances involved in your matter were safe or hazardous.
Potential hazards in the built environment may not always be reasonably or effectively eliminated. Sidewalks are elevated above adjacent roadways and curbs providing certain protection from vehicle intrusion. However, with sufficient speed, a vehicle, specifically large SUV’s and trucks, can mount a curb and invade the pedestrian sidewalk. Placing crash barriers along every curb would be a prohibitive cost, and the barriers would result and/or create new potential hazards.
Building codes, ordinances, standards and practices provide an engineer with a minimum required or practiced value for conditions. An example of this would be a weather event. A minimum design value does not mean or guarantee that a future storm event will not exceed the specified value. This would be where an engineer considers the risk of design minimums. If a storm event occurs and streets flood, this would be considered a short-term inconvenience, whereas a failure of a dam due to a weather event may destroy property and take lives. Therefore, the design engineer considers the risk factors and determines the warrant to exceed a specified minimum value.
Another example is roadway illumination. It is known that improving illumination reduces accidents, but the cost to fully illuminate and maintain this illumination for every mile of roadway is prohibitive. Thus, engineers consider risk and determine where illumination is necessary. This is also applicable for other engineering areas like walkway safety, machine design, and specialized locations like hospitals.
The evaluation of an accident or injury sometimes includes whether there is a design warranted enhancement beyond a minimum requirement or practiced level of care. The National Safety Council defines that risk is a measure of the probability that a hazard may cause an incident and the severity of the adverse effects. The NSC further explained, risks are acceptable if they are judged to be tolerable, which leaves it to engineers to navigate this difficult conundrum deciding what risks are tolerable.
When risks are found to be tolerable, such allowances are customarily tied to warnings and instructions. Where cars are operated at posted speed limits and with sufficient clearance to perceive a hazard ahead, accidents can be avoided or hopefully will be non-life threatening. In other words, safety often involves two parties: not only a designer/owner/maintainer, but also the user. Inattention cannot be designed away. For example, machine operation control requiring the use of both hands aids in securing attention.
Codes, standards and practices provide a minimum standard of care. Certain conditions or circumstances of use in the built environment may warrant safety considerations to exceed a minimum requirement for design, construction, or maintenance. Both Plaintiffs and Defendants have the same investigative path to travel. The built environment is constructed and maintained with dimensional tolerances that consider reasonable safety in combination with achievable construction/maintenance goals. In other words, the world we live in is not perfect, nonetheless, we want the built environment to be reasonably safe and for people to be reasonably attentive. Understanding this, for certain conditions or circumstances, an expert’s investigation may not be straightforward or uncomplicated. Take the time to speak with your experts to understand the basis supporting their opinions.