At baseline, KPIs of trauma care were slightly better during off-hours compared with on-hours, and mortality was lower among seriously injured patient during off-hours. A quality improvement initiative (the TIF) using built-in decision support prompts improved care strongly in both on- and off-hours and eliminated the mortality difference between on- and off-hours. Use of similar decision support prompts during initial trauma care should be promoted widely in other low- and middle-income countries.