[photo SeattleBusTunnel 300 link]from Flickr
In Seattle in 1987, construction began on what is known as the Metro Bus Tunnel [1][2][3], which is a subway tunnel for buses. The idea behind the tunnel, much like the idea of Bus Rapid Transit (BRT), was to provide faster and more reliable service at a lower cost than that of a rail system. When built, the tunnel had the magical feature of being able to accommodate rail in the future. The future is now as the tunnel is being converted to accommodate light rail. This tunnel, with both rail and bus, will be a huge asset to Seattle's transit system.
Putting buses underground, something that has been traditionally only for rail, led me to the West Somorset Railway's Road-Rail experiment. In the 1980s, the railway tried to use buses on its rail lines so that they could be integrated with stations, but also serve suburban areas. The buses had retractable wheels to be compatible with road and rail. Imagine AC Transit buses using the transbay tube to avoid all of the traffic and then being able to use the streets to drop off passengers. Travel to and from the East Bay would be a lot easier and faster.
Another idea, the guided busway, has been put into effect in many places around the world. A guided busway is basically a bus that is steered by external means like a train. When it leaves the busway, it goes on its individual route. The O-Bahn Busway [1][2] in Australia is a prime example along with the busway in Cambridgeshire in the United Kingdom. Buses have a lot of potential to provide rail like service at a lower cost to rail. I support busways, bus tunnels and other forms of BRT as a precursor to eventual conversion to rail. They serve as a middle step in the process of rerailing the the United States.