Resumen de la tesis en inglˇs:
This study reflects on the Typography that can be applied on the sign system in Portugal. Through a historical analysis of the Typography applied to sign systems in the world that use the Roman alphabet, more particularly in the Portuguese found that signa systems mostly have a sans serif typeface. It was also found that, in Portugal, the typeface selection falls in two different families of typefaces. Since the 60s and mid 90s of the twentieth century, the Portu-guese sign systems showed a linear font Neo-Grotesk, such as Helvetica, which reflected the modernist thought from the designers and architects of that time. Only at the 90Õs, the designer started to choose another fonts for  the new sign systems in Portugal, which are the linear Hu-manists. Thus, this study aims to assess whether this change in the typography of sign systems in Portugal reflects in the efficacy of reading these same sign systems.To evaluate the efficacy among the users of the sign systems in Portugal, it was showed to them plaques were presented two fonts, Helvetica, as a Linear Neo-grotesk and Gill Sans as a Linear Humanists. The plates had three degrees of diffculty reading, but also presented with two di-fferent types of contrast, black typography on a white background and white typography on a black background.This study concludes shows very similar results in best time to read in both fonts, with better results for the Helvetica font, except in the highest degree of reading. It is also, show that Helve-tica had the worst results in reading times and, here the difference in both fonts were signi?cant. Which leads to the conclusion that the differences between the two types of letter is not relevant for those who read frequently, but for those who usually donÕt have. This study also concludes that Helvetica is font the users like must.The importance of this research applies to graphic designers, as well as the academic world. This study aims to answer questions about typography applied to signaling systems, particu-larly in Portugal. How does the evolution of taste is re?ected in the effectiveness of reading difrent fonts.