THE in-house fleet department of Carillion and its erstwhile sister Tarmac is trialling a Toyota Prius as part of a wider corporate initiative to minimise emissions of greenhouse gas carbon dioxide. Wolverhampton-based Carillion Fleet Management was formed when Tarmac split into two publicly-listed companies - Tarmac, the heavy building materials operation, and Carillion, the construction company.

The fleet management division is now owned by Carillion, but looks after both companies' fleets, representing a total of 4,500 cars and 750 vans. The vehicles' environmental impact is under close scrutiny by Carillion Fleet Management, which has built a computer model to assess the potential green benefits and disadvantages of various fleet strategies.

Carl Lindley, Carillion Fleet Management's director and general manager, said: 'We have quantified our CO2 emission and measured its sensitivity to different criteria such as changing our fleet content of diesel and liquefied petroleum gas, capping cars by engine size and reducing our average business mileage. Carillion is mindful of the environment and is looking at every way of mitigating its emissions.'

The Toyota Prius, which achieves clean emissions through the combination of a 30kW electric motor at speeds below 10mph and a 1.5-litre petrol engine at higher speeds. 'The economy is there, as is driveability and the cutting-in of the electric motor is fairly seamless,' said Lindley. 'At this early stage we need to be sure that economy and emissions claims are valid, and understand the front-end costs and residual values.'