Two different typical traffic mixtures may be selected for this analysis. Applications with little or no truck traffic (such as light duty parking lots, residential streets, and low volume roadways) should assume 98% Autos and 2% Single Unit Trucks (typical delivery truck). With increased traffic volumes or higher percentages of truck traffic (including any 18-wheel semi trucks), we recommend selecting the option for 92% Autos, 5% Single Unit Trucks, and 3% Combination Trucks.