Mass transit

1) Subway (ie underground) or surface heavy or light rail system for moving large numbers of people quickly over relatively short distances (eg commuter traffic).

Marshalling area

1) Assembly point for people/vehicle/goods to comprise a vehicle load. See also Load assembly.

Market/market place

1) The area (or area of demand) in which a firm trades or plans to trade.

Marginal costs

1) The costs of producing one further unit of output, or performing above the standard (ie when all fixed/overhead costs have been recovered). In transport, for example, the additional costs of adding an extra delivery when all fixed costs of the route have been covered by the other deliveries (ie leaving just the extra fuel, vehicle wear and driver time to be recovered).

Manufacturer's plate

1) Plate fitted to goods vehicle/trailer by manufacturer to show maximum weights for individual axles and vehicle/vehicle-trailer combination at which it is designed to operate (ie design weights).

Manslaughter

1) See Corporate manslaughter.