I've seen many threads about I-5 & Rt 99, but bear with me for asking about them again in a general way: From the intersection of I-5 & 99 south of Bakersfield, to where they intersect again in Sac...
More on-ramp activity on 99. Always merging left and right. On I-5, with traveling the same speed as the big rigs (about 65), I was able to sit in the slow lane for most of the trip without merging back and forth all day. JMHO