I work for a local authority and have been looking at the same issue. Try looking at why people dont cycle to work and the issue will boil down to a fear of cycling in traffic. We have the CTC on board who are offering on-road training for those who havent cycled in a while, a cycle route planner which highlights quiet routes, and a bicycle user group that offers a buddying service. For it to be a success the change has to be supported by ongoing events, I am thinking about evening rides after work for socialising, not far, not fast.