Recent trends predicted by the Petroleum Industry are showing an increased demand for diesel fuel. This is because of the increase in diesel vehicles in North America due to the excellent fuel economy of the diesel engine. This trend will, however, tax the crude barrel for diesel fuel owing competing demands for jet fuel, kerosene, and heating oil.A way of overcoming the projected shortages of diesel fuel is through the use of specially designed flow improvers. These additives enable the blending of higher cloud point winter diesel fuels while maintaining satisfactory low temperature performance.A series of winter field tests have been conducted to demonstrate the effectiveness of these products. In over-the-road tests it was shown that flow improved diesel fuels will operate satisfactorily down to 6-13°C below their cloud points. The actual performance was found to be dependent upon the fuel/additive combination and the particular engine fuel system design. The installation of a larger fuel filter on one of the critical engines and a fuel-line heater on another, further improved the low temperature performance.The results were used to confirm that the Low Temperature Flow Test (LTFT) can be used to accurately predict field results.