buses Unmanned buses are tested in Italy. 2GetThere

Sorry, Google. Some public transport experts think that driverless buses — not robotic cars — are the real future.

The advantages of unmanned buses over the car equivalents is discussed by public transit planning consultant Jarrett Walker in a post on his blog " Human Transit" and is based on a letter from Luca Guala, of transport thinktank Mobility Thinklab.

In his note, Guala concedes that driverless vehicles have a "bright future" but are not as practical as driverless buses, which are particularly beneficial on highly-congested roads. He writes:

Driverless cars very likely have a bright future, but cars they will always be. They may be able to go and park themselves out of harm’s way, they may be able to do more trips per day, but they will still need a 10 ft wide lane to move a flow of 3600 persons per hour. In fact, the advantage of robotic drivers in an extra-urban setting may be very interesting, but their advantages completely fade away in an urban street, where the frequent obstacles and interruptions will make robots provide a performance that will be equal, or worse than, that of a human driver, at least in terms of capacity and density.

Driverless buses, Guala argues, are more efficient because they can carry more people than cars and eventually may be cheaper than the regular bus system because you don't have to pay a driver. The driverless buses are kind of like an updated tram system, such as London's TramLink, but it doesn't need tracks. And since everything is automated, it also means fewer delays.

Another advantage of driverless buses over cars is that they follow set routes, so they are much easier to implement and run. The routes can be changed if needed. Navigation is less of an issue when compared to cars because buses use travel specific lines — they aren't roaming all over the place. Alongside legal technicalities, this has traditionally been the biggest challenge to overcome if automated technology becomes synonymous on roads.

" The future must be evolved , which means that we must plan for the interim state in which some cars are driverless and most aren't," Walker says in his blog post. "That is a situation where driverless buses could thrive, because they will be competing with something that — in terms of poor capacity utilisation — resembles today's traffic on major streets, not a world optimised for the driverless car."

Driverless cars, on the other hand, don't take population growth and the current road infrastructure fully into account. Not everyone will drive them, Walker argues, and so managing two very different ways of getting around will be difficult.

Guala explains further:

Driverless buses, on the other hand offer an interesting feature: the human driver is no longer needed, removing an important cost and several constraints. This allows them to serve efficiently and economically low-demand routes and time bands, while allowing [agencies] to concentrate the number of manned buses on high demand routes at little added cost.

Guala's assessment is based on a test this summer of driverless buses in the small Italian town of Oristano. The buses ran alongside other traffic and carried passengers at frequent, timely intervals, according to the organisation behind the scheme, CityMobil2.

buses2 A driverless taxi in France. Frederic Lelan

CityMobil2, an EU-funded group created in September 2012, has set up a pilot program for automated road transport systems across Europe. Some of its minibuses operate under the 2GetThere brand, heralded as "sustainable mobility solutions". Objectives include less congestion, safer driving, and improved speed. City candidates for the project include Trikala in Greece, Casa in France, and Brussels, Belgium.

There's still a big push for driverless cars —  business secretary Vince Cable says some form of automated technology will be trialled on British roads in 2015  — but Walker ultimately thinks that "shared" transport is a good investment. Which means Google might want to start looking into buses.

Check out this clip of one of 2GetThere's Rivium minibuses: