This study is aimed at evaluating whether symbolic hazard road signs can improve bend curvature estimation which is 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. The results indicate that the influence of hazard road signs is present only in the case of an explicit processing of the bend curvature. This shows the importance of clearly defining the level of processing implied in the steering task target component so as to determine the appropriate information to be transmitted to the driver.