WE refer to the letter headlined, ''Bus drivers haven't changed'' (South China Morning Post, March 10) and the previous letter headlined, ''Fine service'' (Post, February 25), both of which had regard to the quality of our drivers operating routes 6/6A toStanley. Whilst we were delighted to find that your first correspondent was so satisfied with the ''fine service'', we were naturally concerned to learn of the ''shrieking passengers'' witnessed by your second. We would like to take this opportunity to reassure readers that all drivers are trained to ensure the safety and comfort of passengers at all times. As a means of monitoring driver performance and indeed achieving continuous improvement, we have recently introduced a system of ''ride checks'', whereby both uniformed and plain clothes supervisors regularly travel around our network in order to objectively assess ride quality. Although from time to time, we find it necessary to dispense with the services of certain staff, we do pride ourselves in our ability to screen out the wheat from the chaff during our stringent recruitment process. We have certainly not employed former route 6 drivers on a lock stock and barrel basis! MARK SAVELLI Divisional Manager (South) Citybus Limited