A speech synthesizer for a highway advisory information radio system

This paper describes a highway advisory information radio system (highway radio system) and a speech synthesizer that is used in it. The Japan Highway Public Corporation has been developing highway radio systems which collect traffic information and automatically broadcast it using a speech synthesizer in order to improve safety and convenience of driving. In such systems, detailed and appropriate information, immediacy, and plain style message are required. However, this is very difficult and an usual speech synthesizer to handle a large variety of messages is required. The authors have developed a new speech synthesis method. In this method, pitch periods of an utterance are modified and sentence intonation is generated automatically when speech data are concatenated. Thus natural sounding sentence speech can be synthesized from shorter speech units such as words and phrases. Moreover, the highway radio system updates messages every five minutes with high speed processing, and generates appropriate messages based on evaluation of the importance of collected information. This highway radio system has been working since November 1992 on the Tohoku Expressway and two other expressways