From: larry_scholnick on
Yesterday I had the distinct displeasure of being stuck behind a
driver with Acrophobia (fear of heights) on the I-405 to I-5 carpool
lane flyover near El Toro, CA.

As is the case with most carpool lanes in Southern California, the
lanes are simultaneously express lanes that can only be entered or
exited at designated locations (usually about once every 2-3 miles)
and carpool lanes.

At the "El Toro Y" (as it's called on local traffic reports) there is
a separate carpool lane interchange so that those in the southbound
I-405 carpool lane do not have to use the congested regular lanes in
order to reach the southbound I-5 carpool lane; instead, the carpool
lane is elevated over all other parts of the interchange.

So, I'm driving in the carpool lane behind a Toyo Taco-Rolla who has
been barely holding 65 MPH. As the carpool lane begins its ascent he
slows to 55. By the time he reached the highest point of the
interchange he had slowed to 45. Flashing my brights and honking my
horn had no effect. His speed was nearly back to 65 when he returned
to the safe comforts of ground level.

On the way back later that evening I experienced the corresponding
northbound transition at 70+. The northbound carpool lane on I-5
widens to 2 lanes, the left lane marked I-405 and the right lane
marked I-5. The lanes subsequently separate and the transition from
I-5 to I-405 soars above the main interchange.

I did find a link to a picture of the interchange:
http://members.cox.net/mkpl/interchange/eltoro-y.jpg