Predicting stress changes in the subsurface leading to failure or seismicity remains challenging. Developing a robust monitoring method can help the prediction and thus mitigation of natural hazards. Ultrasonic transmission experiments were performed on Red Pfaelzer sandstones to investigate the forecasting potential to failure at different confining pressures. The forecasting potential for failure of the energy of the direct and coda wave, the transmissivity, Q-factor, coda wave decorrelation coefficient, and velocity change by coda wave interferometry are investigated and compared. Our results show the failure of the tested samples can be forecasted from 40 to 70% of the failure point. Small differences are visible in the precursors between the tested confining pressures, but as the trends are very similar, a robust prediction of failure can be made by combining the various analyses techniques. In this paper, we propose a traffic light forecasting system using active acoustic monitoring which is applicable for forecasting failure at various depths and or stress conditions, for a better prediction of small stress-induced changes in the subsurface and thus mitigation of failure (and seismicity) in the subsurface.