Earlier quoted context omitted.
High speed rail is breathtakingly expensive, especially in urban areas. When BART was planning on a high speed branch out to silicon valley, it was budgeted to run $120,000,000 per mile of track. Part of the cost is that you cannot have any at-grade crossings, every road crossing has to be an over/underpass.
> High speed rail is breathtakingly expensive Expensive yes, breathtakingly no. The recent LGV Est ( http://en.wikipedia.org/wiki/LGV_Est ) has a budget of 4b€ for 406km (252 miles) or about $20m/mile. London's M25 projects £6.5b for 117 miles, so urban motorways are not cheap either. Completely urban stuff is very expensive, but usually HST is mostly out of urban systems, only getting in to land at a given stop and…
French HS train lines are for passenger traffic only, they can be (and are) built adjacent to existing highways and so. And of course. They are built as whole new lines, instead of the (not only) German patchwork.
Btw. you are missing HS railways in Spain, where it is built in a similar manner to France, there are already complete operational routes, and the service seems to be very successful as well.