Spring 2009 Update: Great News!
I'm pleased to report that this "Dangerous Intersection" is a thing of the past, thanks to the responsiveness of the NYC Department of Transportation and Margaret Forgione, DOT Manhattan Borough Commissioner. On May 4, Forgione emailed:
Our Borough Engineering Office completed an investigation of this location. As a result, a new order was issued to establish a “NO STANDING ANYTIME” zone south of the bus stop at West 104th Street to include the east-west crosswalks at West 103rd Street on the west curb of Riverside Drive. This is being implemented to improve the visibility of on coming traffic around the curve and improve the safety environment of pedestrians and cyclists crossing Riverside Drive. This order has been submitted to our sign maintenance unit for installation.
And here are the results after daylighting: a clear view of oncoming traffic, and a new, safe crossing:

Thank you DOT, "If you see something say something," isn't just a good thing to do if you see a suspicious package: with this kind of responsiveness from DOT, it can also help us eliminate dangerous intersections. -- Peter Frishauf 5/31/09
Here's how the same intersection looked before daylighting, just a few months ago, when I first wrote about this intersection on StreetsWiki:

Below is the original February, 2009 StreetsWiki post:
Here's another crossing that I've brought to the attention of DOT's Margaret Forgione -- our heroine who fixed one of the crossings at Riverside & 79th Street. following a posting in the Dangerous Intersections Livable Streets group. As with 79th Street, she's promised to look into this one, which is at 103rd Street & Riverside Drive.
As with 79th Street & Riverside, the problem at 103rd Street is the dangerous lack of visibility between pedestrians, cyclists, and oncoming street traffic. It directly effects everyone leaving the park at this heavily-used intersection, (those crossing Riverside Drive from west to east).
It's a big deal because the 103rd crossing is the access to the popular soccer fields, a dog run, the Greenway, and (during warmer weather) to the Hudson Beach restaurant on the promenade & 105th Street. Every day kids (often in a hurry to get home after soccer) come streaming out of the park and onto the street from here.
As you can see from the image of the father pushing his child in a stroller, because the street curves, if you are crossing from the park side to the east side, your view of oncoming traffic is blocked by parked cars. As there is a bus stop just north of the crossing, the street view is often blocked even more. Here's another image shows the crossing from the east side looking toward the park:

The safest solution would be to eliminate the 4-5 parking stops between the bus stop and the intersection. --pfrishauf 2/15/2009