Lusi, most years there are no accidents, some years one or two. But at five to ten miles per hour, most accidents are minor. I know vehicle pedestrian accidents aren't always so.
I think that most of the reason for no accidents is due to luck more than anything else. Sure, in the villages, the posted speed limit is maybe 30 MPH and people are driving slower than that. But this is a state highway, and outside of the villages it's a winding, hilly road and the posted limit is in the 50s. And there are vendors set up out there too. People just park their cars and wander across the road as if it's a parking lot without a care in the world. I work weekends and with a woman from Cortland. She generally uses RT 90 to get to work in Seneca Falls. The first year she encountered this traffic fiasco, she nearly hit three idiots who acted as if they weren't walking across a highway. Now, she is wise enough to detour and use 41 instead. Of course, that lengthens her commute a bit.
It's a nice idea, but a lousy idea for anyone who actually wants to use RT 90 for it's intended purpose.