This research examines service quality perceptions in the transportation industry. First, it analyses the theory about service quality conceptualization. Then a modified SERVQUAL instrument is developed, and applied to the inter-city industry using as subject one of the largest Portuguese bus companies: Resende. The present investigation critically analyses SERVQUAL: an instrument that its authours - Parasuraman, Zeithaml, and Berry - want to be general application. It determines the service quality dimensions of the bus industry, and quantifies Resende’s service quality. Five service dimensions are identified: READINESS/RELIABILITY, TRUST, COMFORT, SECURITY, and ACCESS. They are examined in terms of their impact of customers’ overall quality perception and their willingness to recommend the firm to a friend. These variables are found to be affective heavily by two dimensions: trust and comfort. T