Running boards – especially the broader, 6-inch ones – can keep at least some gravel, pebbles, loose asphalt, and other debris from hitting your car and damaging the paintwork. However, that is not to say that some debris won’t be flung high enough to cause scratches.  A more effective block against gravel and other debris is formed by adding mud flaps to your pickup truck along with the running boards. If you’re only driving in the city and on well-scraped dirt roads, running boards can effectively block debris from hitting your car and causing damage.