Now that's really cute!

very cool. but would need to look into the impact on fuel efficiency form the added weight.

Cute, but beware of hard breaking :D

not to mention whether he uses fertilizer...he probably waters his "lawn" in the morning, to avoid evaporation during the day.

neat concept. if I weren't sure it would ruin my cars' paintjob, I'd do that in a second! my car sits in the street all week...I don't drive to work.

I would bet the decrease in fuel economy due to drag is more than losses due to the AC compressor. Although I doubt this would even stay on at speed anyway.

Yeah, though if you have a black or dark colored car, it may help dissipate the urban (or parking lot) heat island effect, and it would also (depending on the species used) have the possibility of sequestering carbon... though it wouldn't increase efficiency, it would save you carbon emissions in other ways if you didn't drive much.

There's an interesting product from Argentina that I posted about here:
http://www.treehugger.com/files/2006/10/grass_to_go_by.php

A grass that doesn't need dirt and therefore could be useful for things like this.

Okay, so maybe this is a crazy idea but I seem to recall reading something about the impact of white versus darker colored cars at one point. Is it the environmentally reasonable thing to buy white cars in the future, or perhaps even paint our old cars white? Yes, this is a serious question as my old van is just about to bite the dust.

(alternate story)
NEWS FLASH: Indian taxi driver grows his own biofuel on the fly. Clippings-catcher on lawn mower in the trunk is directed to an on-board biodiesel maker. Between passengers, driver cuts enough genetically-modified super-fast-growing grass to fuel the next stint.

Very fun.

But he'd be better off putting in some closed cell foam insulation above the headliner and keeping the roof well waxed.

It's not very fair to the grass. Likely to dry out and brown up if it's not watered often, then you'd get erosion!

I saw this as art; a statement about green roofs. Very creative, and very inspirational.

Unfortunately, the treehugger peanut galley once again found things to complain about, taking the clean air out of my bubble.

Maybe he produces fuel from his lawn clippings to compensate for the added drag and weight. Did you factor that into your calculations? Perhaps sugar cane or switchgrass is next for this taxi. Add a couple goats for methane and dairy production, or even some free range chickens on top would be cool.

Yah, screw the drag issues. I like it! Everywhere I see green, it lifts my spirits. When I look up at an apartment building and trees trees and flowers on a balcony, it makes my heart soar. And this would be the effect his green roof has on everyone he drives past. Toyota should give this guy a free Prius to put his roof on.

i agree with Tim. sometimes, a good idea shouldn't be dissected.

sure, there are fuel efficiency issues. there are also fuel efficiency issues if you drive your grandma to the store instead of going alone.

if he can grow a garden on the roof of his cab, power to him. he should be commended not critiqued.

I have to agree with all of you. The positive person in me really likes the idea especially for my kids because their carseats and seat belts wont burn their skin every time we put them in the car. Cars get so so so hot here a green roof would be most pleasant. But the negative person in me does wonder about fuel efficiency and erosion and wants to make not that if this patch of grass doesn't stay put it could cause danger to the drivers behind me. I guess I would have to know more about this project but I do love the idea. Now if only parking lots would have more trees for shade.