In this article, we formulate a hybrid model that allows to identify the triggers of instant utilities using psychophysiological indicators (PPIs). Instant utilities are understood as momentary emotions perceived in every instant of an experience. We build the model using transport and environmental variables associated with the experience to explain instant utilities, which are measured by PPIs and stated emotions. The model is estimated with data from a real-life travel experiment, in which SKT (skin temperature), HR (heart rate), HRV (heart rate variation), and EDA (electrodermal activity) were measured with a wristband. In addition, environmental variables such as CO2, noise, brightness, and temperature were collected and used to explain instant utility and to control for variation of PPIs. As emotions can be discomposed into at least two dimensions (valence and activation) we capture this multidimensionality estimating two independent models that explain the valence and activation of stated emotions. To analyse what is gained by including physiological data, these models are compared with baseline models without PPIs. Our main findings are: (1) instant utilities are sensible, for instance, to the travel mode; velocity; crowding; brightness; temperature; and humidity; (2) PPIs help to identify the effect of stimuli that cause small variations in the underlying emotions; and (3) instant utility has heterogeneous effects on PPIs across individuals, implying that it is necessary individuals-specific considerations to infer instant utility from PPIs. We discuss the potential applications of this framework in the evaluation of travel satisfaction and demand estimation.