Phytokinetic Bus

Green light: No Photoshop here, this is a functioning public bus with a real garden on top.

Phytokinetic Bus

The bus, currently operating in Girona, Spain, is the first of its kind in the world.

Phytokinetic Bus

It was developed by landscape designer Marc Grañén, who has dubbed (and patented) the Phytokinetic roof garden system.

Phytokinetic Bus

Grañén doesn't use soil, which would be too heavy and negatively impact the vehicle's performance. Instead, he uses an ultralight, thin hydroponic foam that holds humidity but not water.

Phytokinetic Bus

A stainless-steel netting anchors the plants and shrubbery in place, while condensation from the bus's air-conditioning units water the garden.

Phytokinetic Bus

The roof garden, here seen applied to a semi, acts as a terrific insulator, and tests of these first applications have revealed that vehicle interiors can be significantly cooled by it. That means huge savings in energy.

Phytokinetic Bus

Grañén recently completed a roof garden for said semi and a delivery van, the latter which he will exhibit at a green expo in Nantes, France, September 9.

Phytokinetic Bus

All of his projects have met all legal safety codes, so when he says these aren't prototypes, he's right.

Co.Design

Why Not Put Green Roofs On Buses?

A landscape artist envisions a future of public transport when all buses and vans sport greenery.

Tourists in Girona, Spain, may have noticed something strangely pastoral about the city’s public buses. Or just one in particular. The Phytokinetic Bus is painted green, has a green roof, and shuttles visitors to and from a nature reserve. More important, its creator says it's truly sustainable transport. Very verde, and the first of its kind in the world.

Seen from the sidewalk, the extraordinary nature of the autobus is barely visible. Only a few tall weeds indicating its existence, and it would be easy to suspect your usual thin layer of greenwashing. Then you notice the actual garden, a hearty, if scrappy, plot of shrubs and (some) flowers.

The PhotoKinetic bus is a creation of Catalan landscape artist Marc Grañén, who hopes it's a precedent for future vehicles-turned-mobile gardens that will contribute to the health of dense cities. "Urban green areas are crucial for phyotosynthesis, vital for purifying the air we breathe," he says.

These roof gardens in motion function as CO2 sinks. The Phytokinetic roof absorbs CO2 emitted by the bus as it makes its way across town. The plantings release oxygen that helps clean the air and mitigate environmental heating. The garden also naturally cools the interior of the bus, giving the air conditioning system a break and, as Grañén tells Co.Design, leading to "huge" energy savings. Tests revealed that the prototype roof significantly lowered temperatures inside the bus by 3.5C (38.3ºF).

"Many people are worried about the extra fuel burned for the extra weight that represents the Phytokinetic roof," says Grañén, who explains that his prototype more than compensates for that, as the roof he’s designed is incredibly lightweight. He swapped soil out for a hydroponic foam just 2.75 inches thick. He then treated it with an impermeable spray that traps humidity but sheds water. The thin covering keeps the weight off the bus’s frame.

The garden is watered using condensation drawn from the bus’s air conditioning conduits, which are sandwiched between the ceiling and the plant bed. A stainless steel mesh anchors the foliage so there's no risk of it spilling over the sides of the bus or onto its front windshield should the driver makes a sharp turn or hit the brakes.

Grañén emphasizes how grounded the vehicle is in the complicated legality of the city and public transport code: "It runs with all the required legal permissions and certificates and, furthermore, has passed all the security tests."

The system is already a patented reality, near-ready for distribution and expansion, which, of course, Grañén is busy developing, in diverse applications. He recently completed a garden roof for a van that similarly passed inspection; he will exhibit it on September 9 at the International Green Infrastructures expo in Nantes, France. He’s also working to graft his gardens onto electric buses and prototyping new watering methods. It's a fertile plan to put in motion for our cities.

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4 Comments

  • Mario Encina

    I think that it would be better and more useful to put solar panels instead.

  • Richard Lawrence

    Minor conversion typo: a 3.5°C reduction is equivalent to a 6.3°F reduction (not 38.3ºF).

  • davejenk1ns

    Dumb.  No matter how 'lightweight' he claims the garden to be, it's still going to decrease the fuel efficiency of the vehicle.  Even 10 kilos will cost hundreds of dollars over the lifetime of the vehicle.  Moreover, the Styrofoam substrate that he's using came from.... yep, fossil fuels.

    I'm all for green roofs-- but please put them on top of large stationary structures that add to the heat island.  Better yet, tear up the asphalt in low-traffic low-speed areas and let the occasional vehicle drive on the grass.