A Health and Safety Executive (HSE) investigation found Van Chuyen Le, who was employed by Cambus, trading as Stagecoach East, lost control of the bus as he negotiated a gap in the guided section of the busway - a dedicated route for guided buses which joins Huntingdon and Cambridge - on 22 February 2016.
The bus jumped over the track, travelled across an adjacent path and came to rest on the side of an embankment. Five of the bus passengers sustained injuries, which included a fractured spine, pelvis, ribs and whiplash.
Huntingdon Magistrates' Court was told on 9 August that Le was reading a time duty card while driving and was not paying attention to the busway ahead. At the time he wasn't gripping the steering wheel and was driving at speeds of 84 kph when the maximum recommended speed for the area was 48 kph.
Le, of Kent Road, Huntingdon, pleaded guilty to breaching s 7(1) of the Health and Safety at Work Act.
HSE inspector Nigel Fitzhugh said: "Drivers of guided buses must remain vigilant at all times. It is especially important to do so when driving on guided sections as the absence of steering control may create a sense that full control of the bus is being maintained."