Roadside pickings?

[*stuffed*]

I have decided to make some rowan jelly, bramble jelly and rosehip syrup as there are plentiful supplies near me. My question is this, I know it is better to avoid picking stuff from near busy roads but what is considered busy? I don't consider the roads around the estate I live on to be busy, well apart from the main road going through the middle of it. There isn't a steady flow of traffic and doesn't get busy at any time of day, but it is not some quiet little place in the middle of nowhere that is lucky to see one car an hour either.
I am interested in your opinions on what is too busy?

[Andy Hamilton]

A motorway! I live near the M32 and don't pick anything near there.

good question though really. I used to get my fruit and veg from the bus station fruiteers in Bath which is exactly as it sounds a green grocers in a Bus station! I don't think it did me any harm. I don't really see the harm in picking stuff by the road side unless it is a really, really at least four lane busy road. I sometimes wonder if the food I get is tainted when I pick it from a roadside but unless the plant looks particually grey or unhealthy I take it!

[mrsflibble]

I go to a green grocers in a bus station, but I wont pick anything by the side of the A127.