model of lorry under test in water tank
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Using water to improve lorry designs

4 February 2016 Last updated at 00:24 GMT

Lorry drivers clock up around 16 billion miles in Britain every year, so anything that saves even a little fuel could have a big effect on delivery costs and on the amount of pollution they kick out.

Experts at Cambridge University's Centre for Sustainable Road Freight have developed a new trailer design that makes the lorry more aerodynamic - cutting fuel consumption and pollution by around 7%.

The BBC's Transport correspondent Richard Westcott went to the lab at Cambridge to see how they came up with their new shape.