  New and previously published measurements on the deep inelastic $ep$
scattering cross section by the H1 and ZEUS collaborations are presented. The
uncertainties can be significantly reduced by a model independent combination
procedure, which treats the systematic error correlations in a coherent way.
The combined H1 and ZEUS measurements of the inclusive neutral and charged
current cross sections are used to perform a common NLO QCD fit, called HERAPDF
0.1. The resulting set of parton density functions (PDFs) have a much improved
experimental uncertainty compared to previous extractions using the uncombined
H1 or ZEUS data.
