Actually, engineering often involves anticipating errors and compensating for them, since zero error rate (especially over a lifetime of use) is often impossible or far too expensive. For example, a few decades ago, cars started coming with dual hydraulic systems for their brakes, so that a leak in one system would still allow the car to have some braking ability on the other system instead of losing all braking ability, resulting in a much higher risk of a crash. Cars also have features like seat belts that can help if a crash still occurs (sometimes on the part of the driver which is much less under the engineer’s control, although human factors or ergonomics problems in engineering can affect how frequently human drivers make errors).
Of course, not all types of errors are of the same magnitude in importance. For example, on an airplane, an error that causes engine failure while taking off is much more hazardous than an error that causes a seat to be unable to recline.