I’ve still got my board from the ‘70’s. And I hated the pebbles too. Lots of skinned elbows back then. I tried to always ride next to the grass so I could make a sort of “controlled” spill.
I had a neat, lime green “California somethingorother” board in the mid 70’s. It was molded plastic with neoprene (?) wheels, shaped like a fish - pointed on front, wide in the middle, and slender at back with a kicked-up tail. It was NOT a long board, but I used it like one - long hills, no tricks.
I was riding down a big hill with my friend timing me for speed when I began the familiar ever-expanding uncontrolled weave back and forth, after missing a big rock. I hung on past the timing line and ditched.
I took three or four GIANT steps and then went into a roll. Very badly sprained wrist, and a big bump on my unprotected head (asphalt), as I somersaulted to a stop in his yard.
The stopwatch said I was doing 19.5 mph. And yes, I tried again, on a better hill. 21 mph with no mishap, according to my friends dirt bike speedometer. That was the last time I did a speed trial... Lotsa fun as a teenager.