In the centre of Glasgow the canal towpaths are loaded with metal gates and dog walkers, plus obviously they are nearly perfectly flat, so I thought they'd be pretty poor training. However, coming back in from Kirkintilloch yesterday on my mountain bike (about 11k) I thought I'd try the towpath to get away from the bank holiday cars. It was the kit - apart from a couple of gates and one speed bump under a bridge (ooo yah), it was water on one side, trees all around, and because it's flat you can pick a gear and settle into a gasping rhythmn - it actually makes it harder to slacken off. I only saw about a dozen people, there wasn't any broken glass I could see...Could be the way forward for training on the bike. You can't be too enthusiastic going under the bridges, though, or you could end up in the water, and you wouldn't want to meet your alter ego coming the other way, but a lot better than being in amongst the cars.