  We used 15 GHz multi-epoch Very Long Baseline Array (VLBA) polarization
sensitive observations of 484 sources within a time interval 1996--2016 from
the MOJAVE program, and also from the NRAO data archive. We have analyzed the
linear polarization characteristics of the compact core features and regions
downstream, and their changes along and across the parsec-scale active galactic
nuclei (AGN) jets. We detected a significant increase of fractional
polarization with distance from the radio core along the jet as well as towards
the jet edges. Compared to quasars, BL Lacs have a higher degree of
polarization and exhibit more stable electric vector position angles (EVPAs) in
their core features and a better alignment of the EVPAs with the local jet
direction. The latter is accompanied by a higher degree of linear polarization,
suggesting that compact bright jet features might be strong transverse shocks,
which enhance magnetic field regularity by compression.
