Problem Plow Snow

Hi! I have a snow plow problem, i got a skidmark but only brake the wheel, he can not plow snow in skidwmark …How other script with snow plow, please help me or skidmark can go to snow plow.

Example: http://gprime.net/game.php/snowplow

Please help me and i beg

I have idea, to paint with transparent textures…
example:
Snow plow

Snow plow can paint transparent it texture snow… can’t paint transparent it road.