The findings from a TransportEnergy study also reveal that although many fleets are willing to drive cleaner cars, little are doing anything about it.
The survey, which polled 100 fleet managers, drivers and manufacturers, also indicated that 75% think vehicles with high emissions should be banned from certain urban areas.
Colin Matthews, head of customer services at Transport Energy, said: 'The survey shows a great will within the industry to do more to cut vehicle pollution levels. However, will alone is not enough. With the grant money that is now available, there is no excuse for companies not to act.
'The congestion charging programme now operating in London is being monitored by numerous local governments and is proof that key urban centres are looking to reduce their traffic flow and improve their local air quality.
'Fleet and haulage companies must act now to curb their emissions, if they are to avoid costs and exclusions that may seriously damage their ability to do business.'
TransportEnergy is a division of the Energy Saving Trust, working on behalf of the Government to improve the environment through cutting emissions from transport.
Mainly funded by the Department for Transport and the Scottish Executive, it has already handed out millions of pounds in grants to fleets to help them purchase or lease alternative fuel vehicles.
Matthews added: 'In reality, using cleaner fuels and fitting emissions reducing equipment can save companies money, it does not impact on vehicle performance and will enhance the reputation of any organisation.
'It is time that companies face their responsibilities and take steps to make a difference.'