A retractable access device (10) for a vehicle (30) having a longitudinal extent when deployed. The access device (steps, ladder, stairs) can have a multiplicity of treads (eg 10a, 10b, 10c.) interconnected in series by connectors (eg 12a, 13a, 14a . . . ) pivotably mounted with respect to the treads, the connectors permitting the access device to contract and extend longitudinally and the treads to be closed together on retraction. The treads may nest together when retracted (3a-3d) and treads can be formed or fabricated in pairs, such that when retracted, a tread of one pair nests between the treads of another pair, and this can be effected for multiple tread pairs. The access device is particularly suited to grader vehicles with limited and awkward cab access and space for access system deployment, not least due to the grader blade arrangement.