UITP

1) International Union of Public Transport. Brussels-based organization representing national public/passenger transport associations.

UIR

1) Union of International Road-Rail Operators. Organization concerned with encouragement of the use of road-rail systems.

UIC

1) Union International des Chemins de Fer. International organization representing rail operators. Equivalent to IRU for road operations.

Tyre groove

1) Groove in vehicle tyre forming tread pattern. Must be at least 1 mm deep (1.6 mm for some vehicles from 1 January 1992) - see Tread depth. Base of the original groove over area of tread to which depth limit applies must remain visible. Grooves can be re-cut on tyres for certain vehicles.

Type approval

1) EU-wide scheme whereby vehicles/components, etc are submitted to national authority (ie DTLR - VCA - in UK) for approval after which they can be sold as 'Type Approved', otherwise may not be sold. Vehicles without type approval cannot be registered in UK.

Two-speed axle

1) Rear axle of goods vehicle containing two crown-wheel pinions for changing between high and low ratios. Operated from cab by vacuum or electrically. No longer popular with advent of multi-ratio gearboxes.