I'm thinking of running my first marathon in Geneva this May. I ran the half marathon last year and had a great time. It's a beautiful course that cuts through fields, parcs and weaves around the lake.

The only complaint I had, which I expressed in a survey the organisers sent me, was that some parts of the route were rather narrow and made it difficult to pass. It took about 12km before the crowd thinned out most likely due to the fact that half-m. runners were being funneled onto the path of the full-m. runners who had started two hours before.

This year, the organisers decided to include wheelhairs and hand bikes on the same route as the half and full marathon runners at the same time! Insanity? 

Am I right to worry?