Looks like it might be a coachwhip? In some areas (where I used to live in CA) they're pinkish to faded red on top, brighter pink ventral, but in other areas may be
plainer brown-tan colors, or even black. They easily get 5-6' as adults, long & slender like this...good snakes, harmless...not constrictors, they gulp down whatever
they can subdue (small rodents, insects, reptiles, birds/eggs)...basically a racer-type snake, fast & hyper, not happy in captivity. Diurnal, sun- & heat tolerant.
It could be a rat snake, except the scales really look like coachwhip scales to me...they got the name for looking like a braided rope.