A jerky ride in a bus can very easily be down to the vehicle rather than the driver. This will be far more noticeable with a bus than a lorry because by the very nature of the job bus drivers rarely get to drive the same vehicle one day to the next; more often than not changing vehicles mid shift. We all know how supposedly identical vehicles behave differently and how we get used to each one’s foibles. I would agree that a good driver can adapt remarkably quickly to a vehicle change, but fierce brakes and snatching clutches can be very difficult to manage smoothly. I’m sure some can recall the Gardner powered LV ERF’s attempt to leap out of bed as the clutch was let in on an incline. The planetary gearbox can be just as much a challenge to operate smoothly as a sliding mesh 'box. While a normal gearbox change is in the hands of the driver to time, a semi automatic planetary 'box will almost certainly be controlled either electrically, pneumatically or hydraulically. The first Routemasters to enter service in the 1950s acquired the reputation as ‘Jerkmasters’ because of the poor quality of the fully automatic gearchange. Move on to more modern vehicles with integrated retarders and individual vehicles can become a real nightmare to drive smoothly. The Scania Metropolitan in London Transport service produced a shocking gearchange because of LT’s modifications to the control system. Add in wear and tear and the Volvo Olympian with the Voith DIWA 'box’s integrated retarder will suddenly and unpredictably come in with a loud bang and a tremendous jerk at some point as the driver attempts to brake for a stop. The ageing Dennis Dart, just like the Metropolitan will not be able to make up its mind which gear it wants to be in as it climbs an incline when revs increase, resulting in loud bangs and jerks - all beyond the driver’s control.