SQL Server 2019

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.
create table rit (ritid int, loadfactor int)
insert into rit (ritid, loadfactor) values (1, 5)

select * from rit


ritid
loadfactor


1
5


select r.ritid, r.loadfactor, cvirtual.ProductSequence
from   rit r
outer apply ( select top 5 --r.loadfactor
                     RitID,
                     CarID,
                     row_number() over (partition by RitID order by RitID) as ProductSequence
              from ( values(r.RitID, 1),
                           (r.RitID, 2),
                           (r.RitID, 3),
                           (r.RitID, 4),
                           (r.RitID, 5),
                           (r.RitID, 6),
                           (r.RitID, 7),
                           (r.RitID, 8),
                           (r.RitID, 9),
                           (r.RitID, 10),
                           (r.RitID, 11)
                   ) as X(RitID, CarId)
              --where  c.CarID is null
            ) cvirtual --on r.RitID = cvirtual.RitID


ritid
loadfactor
ProductSequence


1
5
1

1
5
2

1
5
3

1
5
4

1
5
5


drop table rit