By Linda Kor Travel along Route 66 usually brings to mind polished classic cars in mint condition cruising the route in style. In Holbrook, the cars that usually travel the Mother Road do it for work and sometimes dirty work. To honor those who still use the route as a way of life, the Route 66 Festival: It Ain’t Your Mother’s Road will be hosting the Grit Of The Road dirtiest car contest beginning at 2 p.m. on Saturday, Aug. 9, at West End Park. Competitors will bring their vehicle to display in front of judges to see who will take the prize for the dirtiest car to travel the route. Prizes will be awarded.