Construction firms, groundworks and civils contractors, plant hire yards and agriculture.

Up to 3.5 tonnes operating weight
Theory and practical assessment, carried out on the employer's own machine, on their site.
No UK government body issues a licence to operate a roller, and no statute requires one.
The duty to train and assess competence sits with the employer, under the Health and Safety at Work etc. Act 1974 section 2(2)(c) and PUWER 1998 regulations 4 to 9.
The controls that matter are the same as for a dumper: the roll-over protective structure and the seat belt.
The Control of Vibration at Work Regulations 2005 apply to whole-body vibration, and the Workplace (Health, Safety and Welfare) Regulations 1992 regulation 17 and HSE guidance HSG144 set the wider standard for site vehicle use.
The employer still authorises each operator in writing under PUWER 1998 regulation 9; the certificate, unit credit, records and site evidence statement are the evidence the employer relies on for that decision, not a substitute for it.