Putting the bikes up above the streets means safety for all.
I like it and don't see why we can't do that now -- at least between downtown LA and Pasadena as a trial. It could be built next to the Gold Line tracks for much of the distance.
Actually, part of the bikeway already exists and is very beautiful.
The Arroyo Seco bicycle path is an approximately 2 miles (3.2 km) long Class I bicycle path in Los Angeles, California. The path connects Montecito Heights Recreation Center, Ernest E. Debs Regional Park, and Hermon Park in the Highland Park district, and runs parallel to State Route 110, and ends at San Pascual Stables in South Pasadena.
. . . .
The Southwest portion of the path, approximately a quarter of a mile, runs along the higher ground overlooking Arroyo Seco through chain-link fence, and descends into the floor of Arroyo Seco flood control channel. Following the channel hydraulics, there is a very slight and mostly consistent uphill grade in the northeast direction with some stretches (notably under overpasses) with slightly greater slope.
In addition to north and south entrances, the path is accessible through a pedestrian bridge from Hermon Park. The path crosses several pedestrian and vehicular bridges along the way.
http://en.wikipedia.org/wiki/Arroyo_Seco_bicycle_path
. . . .
The path continues as a equestrian trail from its north terminus. Only horses and pedestrians are allowed beyond San Pascual Stables. However, bicyclists can continue on Arroyo Blvd, a quiet residential street that extends towards Rose Bowl Stadium in Pasadena.
http://en.wikipedia.org/wiki/Arroyo_Seco_bicycle_path
Don't try it if it is raining or has recently rained unless you know the Arroyo is dry. The Arroyo is a waterway when we get rain. (A rare event in the past couple of years, but next year we could have a lot of rain and flooding.)
Also, if you come to LA by train and bring a bike, you can take the Gold Line North, get off at a
the Southwest Museum stop and up to Sycamore Park (not far from the Southwest Museum Stop), cross the bridge and you are at the bicycle path. It is also good for pedestrians and hikes.