Baby robins and a bad nest location

A robin built a nest on the light at my back porch, laid two eggs, and both eggs hatched about five days ago. I've been watching the little family through my window, and the babies seem to be doing well. (I've dubbed them edward and henri.) I have...

kept my spying to the inside of the house and have done the best thing I can do for them, nothing, just left them alone.

Here's the problem. I did a little bit of robin research online to find out when the little ones would be leaving the nest and found that they would leave in about another week and a half, before they can fully fly. that would be fine except the nest is built on my back porch which is separated from the nearest grassy area and trees by a large parking lot. I've become very attached to these birds and don't want to see them stuck in a parking lot where they could get hurt. my question is, should I interfere once they leave the nest and put them in the grassy area, or should I just continue to watch from my window and let the mommy robin deal with it?

Any advice?

I guess I would continue to let nature take its course, they have survived so far- I would allow the mother to keep taking care of them.

if I were to interfere at all it would be in providing something soft for them to land on in the event that their first flight doesn't go so well- maybe a pile of grass or something a few feet around the nest. as long as you do not disturb the nest or the birds you should be ok- maybe even spreading some grass around at night while they should be asleep, maybe something for them to hide in too would be a good idea- if they should end up on the ground- protection from cats.

it is admirable of you so far that you have been concerned but have restrained yourself to let nature take its course- not many people can say they would not seriously interfere and in turn have the birds die because of their good intentions

Thanks for the suggestions. Last night I put a blanket down on my porch under the nest in case the little guys fall. I figured that would be softer than concrete. If they do fall, is it okay to place them back in the nest? I don't want to interfere, but they're not going to stand much of a chance if they wander into that parking lot.