The paper aims to propose the maximum track length (Lmax) measurement as an alternative approach to evaluate and extract the bulk etch rate (Vb) of the nuclear detector PADC CR-39, and compare it with the results obtained by the removal layer thickness measurement of the etched detector. The alternative Lmax-method mainly relies on the measuring the length of the etched tracks, their maximum values and saturation times from the obtained track profile images. The detectors were irradiated with different energies of alpha particles emitted from the 241Am source and then etched in a 6.5 N NaOH solution at 70±1oC for different successive time intervals. In order to calculate Vb, the maximum length of the tracks and their saturation times were determined corresponding to the energies of the alpha particles used. A direct proportion between the maximum length of the tracks and the energy of the alpha particle was observed. However, the value of Vb is found to be 1.344±0.0202 mm h-1 obtained using the Lmax-method, and it was consistent with that computed by the method based on the measurement of the thickness difference of the etched detector which was 1.354±0.065 mm h-1.