Vehicles that come off of the production line are tested at random to ensure that they meet the lab test results.Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window) The tests must be done within a controlled range of temperatures, between 20°C and 30°C to be valid. All of the vehicle’s components must be present and cannot be tampered with. For example, the alternator belt must be intact and the brakes must function fully to pass testing. To measure a car’s official fuel consumption and emissions– the figure which manufacturers use on all technical and marketing material – it must undertake the New European Drive Cycle (NEDC).There are a number of myths that surround the fuel consumption and emissions test. So here, in seven simple points, are the unadulterated truths about NEDC. The vehicle will be checked to ensure it has the same tyre pressures, fluid levels and components as it would have on the road. The vehicle will not pass the test unless it meets the manufacturers production specification and tolerances. The NEDC test must be witnessed by a government-appointed approval agency to ensure it meets the standards set out by the European Commission. Testing is always undertaken in specific laboratory conditions on a rolling road, which replicates air resistance. There is a standard drive cycle that is monitored by a computer programme, which invalidates the test if it is not performed within certain tolerances.