By Paul Hudson for CNN
The drive towards more eco-friendly vehicles isn't the preserve of the manufacturers of passenger cars.
Commercial vehicles also contribute to congestion and emissions, and although few of us spare a thought for them most of us rely on them to transport the goods we buy.
At the UK's premier Commercial Vehicle (CV) show in Birmingham, makers were just as keen to promote their green credentials as the most fanatical auto manufacturers.
British manufacturer Vauxhall unveiled a range of panel vans than run on E30 biodiesel, a mixture of conventional diesel and fuel made from renewable resources, meaning carbon dioxide (CO2) emissions reduced by up to 20 per cent over similar vehicles running on 100 per cent conventional diesel. It is planning trials of two models with a major fleet customer.
As part of a controlled fleet trial, a number of vans will run on biodiesel B30 across the UK as Vauxhall and its parent company General Motors investigate the long-term potential for the fuel in the UK, and look towards a more widespread distribution network for it.
Biodiesel is made from naturally renewable sources such as sunflower and rapeseed oils, where the oil is extracted and transformed into a methyl ester. Biodiesel B30 is a mixture of 30 per cent biodiesel and 70 per cent conventional diesel.
Emissions from the fuel are reduced because plants grown for conversion to biodiesel actually absorb CO2 from the atmosphere.
Although biodiesel can be produced from a variety of sources, quality is critical, and GM is calling on the EU and the UK government to look at establishing a quality specification for the fuel.
Vauxhall's managing director, Bill Parfitt, said: "Fuel efficiency is already one of the top priorities for our commercial vehicle customers. Payload and duty cycles mean downsizing is generally not an option, so achieving further CO2 reductions becomes a real challenge."
"The introduction of biodiesel B30-compatible models is one way GM can help customers reduce their CO2 emissions and is part of General Motors' wider commitment to alternative fuels and advanced propulsion systems -- we're very pleased to be the first manufacturer planning to fully trial the fuel in the UK."
"Of course, governments have an important role to play as well, specifically in terms of ensuring the quality and wider availability of the fuel, and providing incentives to encourage customers to buy it."
The biodiesel B30-compatible vans aren't the only vehicles offered by General Motors to successfully use biofuels. Swedish auto brand Saab introduced petrol-based BioPower vehicles in 2005, which are capable of running on any combination of petrol and bioethanol E85.
The increased use of platform sharing, in which a whole range of passenger cars and commercial vehicles are planned one chassis platform, makes it easier for manufacturers to roll out fuel-efficient technologies.
There's also a drive towards battery-powered vehicles -- particularly for short-distance, urban use -- although hybrids are still seen as the longer-term solution.
The development of wholly electric vehicles has been spurred by the planned Low Emission Zone (LEZ) restrictions in London. Other makers that are simply keen to show their green credentials, through dramatic emission reductions (including carbon dioxide and noise), are showing great interest in diesel-electric hybrids.
As yet, there are no CV hybrids available in the UK market. Most are still at the prototype stage and, as Toyota and Honda have found with their Prius and Civiv passenger car petrol-electric hybrids, involve considerable investment before any profitability can even be considered.
Therefore, in the CV world at least, electric vehicles are seen as viable in the short term. Despite shortcomings in weight, range and performance -- mainly connected with limitations of current battery technology -- they are simpler and less costly than an equivalent hybrid.
Smith Electric Vehicles of Tyne and Wear, whose milk-floats have been used by dairies all over the UK for more than 40 years, unveiled a range of electric vehicles at the CV show
The adoption of sodium nickel chloride batteries in place of the hitherto ubiquitous lead-acid type are at the heart of what is claimed to be the technology breakthrough for SEV. These power packs are about 80 per cent than lead-acid units with the same energy storage, and deliver more performance.
The converted Ford Transit on show has a claimed top speed of 80kph (50mph) in combination with a range of up to 240km (150 miles).
Modec uses the same battery technology for its electric vehicles, and says that UK supermarket giant Tesco will be using the vehicle for home deliveries of groceries. The new trucks can carry a two ton payload, have a 100-mile range and a top speed of 50mph, all on one overnight charge.