A driving assistance method includes: a step of, by a driving assistance apparatus, calculating a power spectrum by a frequency analysis of an acceleration obtained by a three-dimensional accelerometer; a step of, by the driving assistance apparatus, obtaining information on an angle based on a magnitude of an inclination of a single regression line of the power spectrum in a predetermined frequency range; a step of obtaining a speed by the driving assistance apparatus; a step of, by the driving assistance apparatus, calculating a traffic jam sign index as a product of a value associated with a degree of variation in the angle and a value associated with the speed; and a step of, by the driving assistance apparatus, sensing a traffic jam sign based on a change in the traffic jam sign index within a predetermined time.