Heavy-duty truck sales may not be a leading economic indicator, but they should be. When companies make heavy investments in big rigs, they usually expect to be shipping more product, which is good for the economy. With that in mind, sales of heavy-duty trucks are on course for their best year on record, while medium-duty sales are on the verge of a 16-year high. With Class 8 sales of 170,113 through October, the segment should easily surpass the calendar-year record of 185,696 set in 1994. Medium-duty (Classes 4-7) sales hit 159,254 after 10 months, besting last year's numbers by 14.8%. At their current pace, 1995 medium-duty truck sales will post the highest annual mark since 203,921 in 1979.