Results/Conclusions Increased deposition was not due solely to an edge effect. Deposition along roadside edges was higher than along non-road edges. These gradients were short, less than 150 meters, and steep, with most of the elevated deposition occurring within the first 10-50 meters. Deposition near the road (<10 meters) was 1.5-2 x that of areas farther away (150 meters) from the road. This increased deposition was likely due to near-source deposition of mobile source emissions. This deposition has likely been occurring for decades causing changes in, forest floor C:N (-5.3 units), leaching (~2x), in sites near the road compared to sites farther away. When near source deposition is taken into account deposition estimates for a small watershed increase by 10.5-12.5 %.