Pedzisa mutsara unotevera: Matambudziko okurara akapararira uye anogona kuva nemigumisiro yakakomba kuvanhu vanotapurwa pamwe chete nemigumisiro yezveupfumi nemimwe migumisiro munzanga. National Transportation Safety Board yeU.S., maererano naDr. Charles Czeisler, nhengo yeInstitute of Medicine uye Mutungamiriri weHarvard University Medical School Division of Sleep Medicine paBrigham neWomen's Hospital, akawana kuti chikonzero chikuru (31%) chetsaona dzemotokari dzinorema dzinouraya mutyairi chine chokuita nokuneta (kunyange zvazvo zvisingawanzobatanidzwi zvakananga nezvinetso zvokurara, zvakadai sokurara usina kufema), nezvinodhaka nedoro sechikonzero chechipiri (29%). Kushaikwa kwokurara kwave kuriwo chinhu chinokosha mutsaona dzinotyisa, dzakadai sokudonha kwemafuta kweExxon Valdez, tsaona dzenuclear paChernobyl uye
Three Mile Island nokuputika kwechikepe chomuchadenga chinonzi "Challenger".