Self-reports and questionnaires have been the preferred research methods in the criminological field of Fear of Crime (FOC) since its rise in the 1960s. Our study had two main goals: 1) to measure the physiological indicators of fear in real time, and 2) to compare these data with those obtained through self-reports, designed also to measure the emotion of fear. Methods An experimental study conducted in the course of a week during late February 2016 in Aarhus (Denmark), in which the focus was on traditional environmental variables in the field of FOC (i.e., poor lighting conditions). Results Our results support the ideas that 1) the absence of good luminosity in an open public space in an urban setting elicits physiological reactions of arousal that can be taken as indicators of experiences of fear, and 2) heart rate appears to capture aspects of the emotion of fear that are not reflected in data obtained through self-report questionnaires. Conclusions This study, introducing a pioneering approach to the study of FOC, presents great potentials in complementing traditional methods in the crime sciences. The many challenges we faced are significant and reported with the hope the subsequent literature to build on. We propose that traditional methods and new measurements could be combined to advance the research in the field by allowing researchers to more unambiguously constrain the interpretation from their data. This becomes particularly relevant in a field like FOC, that has long suffered from irreconcilable results stemming from different investigations.