I'd imagine that % changes heavily on hour in the day and road observed.
People using truck for work (tradesman etc) do it all thorough the day. People who just use it as status symbol get to work and back from work at given hour. Also probably more usage in weekend when people doing weekend project go shop and people not doing that don't even get out on the longer trips.
Sitting on one road for an hour (and looking at photos, far from peak traffic) is near meaningless
The "peak traffic" that all the 9-5 office workers on HN see is also not when trucks that carry things move. Blue collar work usually starts at 6/7/8am.
People using truck for work (tradesman etc) do it all thorough the day. People who just use it as status symbol get to work and back from work at given hour. Also probably more usage in weekend when people doing weekend project go shop and people not doing that don't even get out on the longer trips.
Sitting on one road for an hour (and looking at photos, far from peak traffic) is near meaningless