Motorists' views of road pricing will depend on how they will be affected, added Mr Holmes speaking at an Institute for Public Policy Research seminar in London.
Mr Holmes said: 'At this stage the potential benefits of road pricing must be spelled out so that people can see that the objectives are worth pursuing.
Mr Holmes suggested a five-point plan to win motorists over.
Mr Holmes said that road pricing represented a fundamental change in motoring taxation. Charges should not be imposed on top of existing motoring taxes but be evidence-based and independently audited.
To maintain public confidence the scheme must be overseen by an independent regulator. Drivers must also see real benefits resulting from pricing - either by improving the road or investing in alternative public transport services.