switch (FEAT_ROADVEHS, SELF, switch_w_l_c_vehs_a, getbits(value, 4, 4) ) {
    0..3:			spritegroup_w_l_c_vehs_aa;
    4..7:			spritegroup_w_l_c_vehs_ab;
    8..11:			spritegroup_w_l_c_vehs_ac;
    12..15:			spritegroup_w_l_c_vehs_ad;
}

switch (FEAT_ROADVEHS, SELF, switch_w_l_c_vehs, getbits(value, 0, 4) ) {
    0..3:			switch_w_l_c_vehs_a;
    4..7:			switch_w_l_c_vehs_b;
    8..11:			switch_w_l_c_vehs_c;
    12..15:			switch_w_l_c_vehs_d;
}