People are riding around on snowmobiles.
People are using snowmobiles as a form of transportation.
transportation is the same thing as riding around
exists e1 x1 x2.(r_around(e1) & on(e1,x2) & n_snowmobile(x2) & Actor(e1,x1) & v_ride(e1) & n_people(x1))
exists e1 x1 x2 x3 x4.(as(e1,x3) & of(x3,x4) & n_transportation(x4) & n_form(x3) & Theme(e1,x2) & Actor(e1,x1) & v_use(e1) & n_snowmobile(x2) & n_people(x1))