Better Read It to Me: Benefits of Audio Versions of Variable Message Signs in Drivers with Dyslexia

Adults with dyslexia may find difficulties in reading the messages on variable message signs (VMS) while driving. These signs are an essential part of the traffic communication systems, aimed at informing road users of special circumstances, such as congestion, traffic diversion, or unexpected events. A driving simulation experiment was conducted to test if complementary audio versions of the VMS would be helpful for drivers with dyslexia. Twenty adults with dyslexia and 20 matched controls participated. They were asked to classify the messages displayed on VMS posted along a simulated route, which was completed twice: one with text VMS (visual condition), and another one with text VMS plus complementary audio messages (audio + visual condition). The results showed that in the ordinary, visual condition, the participants with dyslexia needed to be closer to the VMS than controls to correctly classify the message, but, crucially, these group differences vanished when the driver received an audio version of the message (audio + visual condition). Moreover, the availability of audio versions had positive effects for all participants, as shown by higher accuracy in the message classification task, as well as better driving performance. Therefore, technologies aimed at providing audio versions of VMS can help drivers with dyslexia. A mobile application, READit VMS, which is able to provide real-time complementary audio versions of VMS, is presented as an example.