If you are abreast of someone or something, you are level with them or in line with them. As he drew abreast of the man he pretended to stumble
Up to a certain level or line; equally advanced; as, to keep abreast of [or with] the present state of science
" Side by side; also, opposite; over against; on a line with the vessel's beam; with of
If people or things walk or move abreast, they are next to each other, side by side, and facing in the same direction. The steep pavement was too narrow for them to walk abreast