Airsprung axle (bogie)

1) Axle or set of axles with suspension provided by air bags (see Air suspension).

Air (water) separator

1) Term used for anti-spray equipment on goods vehicle - refers specifically to ‘cats whisker’ type of nylon bristle which surrounds the mudguard valance to prevent water from spraying out but allows air to pass through.

Air suspension

1) Heavy vehicle suspension system that relies on compressed air stored in air bags to provide smooth suspension - mainly used on vehicles carrying goods susceptible to damage or on tanker vehicles where vibration may cause damage to tanks/tank mountings (also on luxury coaches to provide greater passenger comfort).

Air pollution

1) Pollution of the atmosphere (ie the air we breathe) by vehicle exhausts. A comparison of the emission factors between road and rail shows the following general relativity of emissions in grammes per tonne kilometre:

Air-lift axle

1) Retractable (ie lift-up) axle on vehicle/trailer lifted from road surface by means of compressed air to reduce rolling resistance (for fuel economy reasons) and tyre wear.

AIM

1) Alternative investment market. Public stock market operated by the Stock Exchange for smaller, growing companies, management buyouts, etc (ie useful source of funds for the smaller business).