I commute on mine most days.
My trip is much shorter though (only 1.5 miles)
Your only issue will be not getting run over.
Get a big flag, lots of lights and maybe a pistol.
I am in Northwest Ohio and I wish it was as bike-friendly as Seattle.
As for the KMX itself, it would be a good choice.
The braking is very good and balanced.
If you are hauling cargo the available racks are limited.
I built a rack for my X class and included a headrest that is very
nice for longer rides.
In Seattle the fenders are a must.
If the pavement is wet, the front tires throw up a lot of water.
The hookworm tires sling more water than the tires on my wife's ST
class.

Hal

--- In KMXKartsowners@yahoogroups.com, "aprikian777"
<aprikian777@...> wrote:
>
> Hi,
> I am thinking about using a tricycle for commute. Never had one and
doing extensive
> research on different trikes I found KMX. Looks great and not too
expensive, most
> importantly has a lot of options that I like - brakes on all wheels
etc.
> My commute is 15 miles one way and I live in seattle area, so you
can imagine fenders are
> must on all three wheels and very good brakes as well. Also, I like
to go fast 20m/h.
> Any suggestions are welcome.
> Thanks very much.
> PA
>