That's because it is a bus: a production-line fuel cell hydrogen bus.

And as expected from a company as forensically thorough in its engineering development processes as Toyota, the new Games-ready Sora passenger bus is a cut above anything seen before, beating the latest generation battery electric buses on size, range, efficiency and passenger-carrying capability.

With the Japanese government focusing intently on what it calls Tokyo Zero Carbon 4 Days in 2020 and aiming for a sustainable Olympics, Toyota sees this occasion as an international showcase for the types of zero-emission vehicles it wants to sell to countries like Australia.

Hydrogen fuel cell vehicles are electric but don't require the slow recharging times that battery-powered vehicles need.

With hydrogen vehicles, it's top up and go. When liquid hydrogen is fed into the fuel cell stacks in the vehicle, it produces electricity to drive it, with water as the only byproduct.

Although used to provide power for seven NASA space missions as far back as the mid-1960s, fuel cell technology has taken a long time to gather momentum in the transport industry.

But it is now accelerating so quickly, it could kick Elon Musk's bold plans for a battery-powered Tesla semi-trailer into the weeds.

Despite all the hype around electric cars, problems still rest with the existing limitations of today's battery technology.

For years, car makers have been trying to strip weight out of cars to make them more fossil fuel-efficient but with a battery electric car, the burden goes right back in.

The Model S Tesla, for instance, contains 7104 separate lithium-ion batteries all linked together. And those batteries weigh a whopping 540kg.

To move a big, heavy bus or truck, the battery pack would need to weigh many fat tonnes.

Slow recharging, complex fast-charging infrastructure, limited driving range and bulky, heavy battery packs make rechargeable electric vehicles less favoured for heavy transport roles.

That's the view of Australia's Chief Scientist, Dr Alan Finkel, who prepared a briefing paper for COAG last year on why Australia should be investing in hydrogen transport.

"Fuel cell electric vehicles (FCEVs) and battery electric vehicles (BEVs) have complementary roles to play," Dr Finkel wrote.

"[Fuel cell vehicles] have longer ranges and faster refuelling and are particularly well-suited to long-distance heavy transport where the size and weight of the battery required becomes impractical."

The ACT government's own data, recently released by Transport Minister Chris Steel, revealed just poorly the battery-powered buses compared with diesel in a trial.

In a service which depends on range and reliability, the less accommodating electric bus fell down badly with both.

However, that was two years ago. And two years is a very long time in electric vehicle development.

China has built 421,000 electric buses to date and wants to sell as many as it can to the ACT government. The price, amortised by such massive production volumes at home, is bound to be very attractive to Transport Canberra.

But a little prudence would be advised about jumping too early into a multi-million dollar battery bus contract which could prove a costly blind alley to zero emissions.

Toyota will have 100 Sora zero-emission fuel cell buses to shuffle visitors between venues at the summer Games.

However, by 2022 for the winter Games in Beijing, 1000 buses using the same fuel cell technology will be built and operating through a partnership between Toyota and the Beiqi Foton Motor Company.

The volume is building, and the Chinese know how to build in volume.

To its credit, the ACT government has been the first jurisdiction to jump on board with hydrogen and Australia's first public refuelling station is being built in Fyshwick.

Using renewable energy from the Hornsdale wind farm in South Australia to power the electrolysis process which generates the liquid hydrogen, it should be ready by February next year.

Other states and territories are rushing to build them too, so Canberra's front-running status will only last weeks.

Toyota didn't make the cut when the ACT government sought to lease 20 hydrogen fuel cell passenger cars for its 2019-20 government fleet as part of its zero emission aspirations.

Only three car companies in the world - Toyota, Hyundai and Honda - build hydrogen cars in production and the Koreans got the nod for the ACT business, which will provide much needed volume and throughput for the refuelling station.

To add a dedicated refuelling station at each of the Action depots would be comparable in cost to the complexity of a rapid charging network for battery buses which would not only be needed in the depots, but also across the interchanges.

In Los Angeles, where battery buses have been adopted as the basin's much-needed smog-beating public transport, multiple overhead gantries which look like big shower heads had to be built at the depots to deliver the plug-in direct current.

The description "fast charging" is a misnomer. China's latest electric buses get around 200 kilometres on a two-hour charge. What the users won't reveal is the high rate of battery degradation in the older models as a result of the partial discharges, incomplete recharges and the range of other issues which occurs with a fleet constantly being shuffled around to fit a timetable.

Choking smog problems in cities such as Beijing, Shenzhen and Los Angeles forced the hand of the local public transport authorities, which depend heavily on their bus networks to move people around.

The ACT minister has the luxury of a little time to assess all the options, and needs to look at whole-of-life costs carefully

Improved efficiency needs to be better extracted from the 3-4 tonnes of inert bulk carried everywhere by plug-in electric bus viable.

The hydrogen fuel cell bus will certainly be more expensive but worth the investment if the goal is to future-proof the fleet.

And so, let the Games begin.