Two people are riding along the side of the road on bicycles, the one in front is wearing a helmet.
Two individuals are riding bicycles outside.
People are individuals.  They are riding on the road, hence they are outside.
exists e1 e2 x1 x2 x3 x4 x5 x6.(n_thing(x2) & card_eq_1(x2) & n_road(x3) & n_side(x2) & Theme(e2,x6) & Actor(e2,x2) & v_wear(e2) & n_helmet(x6) & in(x2,x5) & n_front(x5) & on(e1,x4) & n_bicycle(x4) & along(e1,x2) & of(x2,x3) & Actor(e1,x1) & v_ride(e1) & n_people(x1) & card_eq_2(x1))
exists e1 s1 x1 x2.(a_outside(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_bicycle(x2) & n_individual(x1) & card_eq_2(x1))