This study aimed to evaluate whether hazard symbolic road signs might improve bend curvature estimation, this last being usually based on visual subsymbolic information. This has been determined as a function of the level of processing implicated in the bend estimation task: implicit or explicit processing. Results indicate that the influence of hazard road signs is present only in the case of an explicit processing of the bend curvature. This indicates the importance to clearly define the level of processing implied in the steering task so as to determine the appropriate information to transmit to the driver.