# The Road Vehicles (Authorisation of Special Types) (General) Order 2003, Paragraph 22

Extent: E+W+S

(1) Engineering plant, or a vehicle-combination that includes engineering plant, which falls within Category 1, 2 or 3 must not travel on a motorway, dual carriageway or other description of road at speeds exceeding the speed specified in Table 10 for that Category in respect of the description of road in question.
Table 10
Speed restrictions for engineering plant treated as falling within Category 1, 2 or 3
Vehicle or vehicle-combination
Motorway
Dual carriageway
Other roads
Category 1
60 mph
50 mph
40 mph
Category 2 or 3
40 mph
35 mph
30 mph
(2) But where the plant or vehicle-combination does not have suspension on all axles, the plant or vehicle-combination must not travel at speeds exceeding 20 miles per hour.

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Source: https://www.legislation.gov.uk/uksi/2003/1998/schedule/3/paragraph/22 (the official version)
Page: https://openlegislation.uk/road-vehicles-authorisation-of-special-types-general-order-2003/schedule-3/paragraph-22
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.