Banned in Delhi for a decade, smog-spewing combustion engine–powered rickshaws are fading away in India and in many other countries, thanks not only to inroads by minivans, but also to  improved rickshaw motor designs coupled with laws to mothball dirtier models. In January, for example, Jakarta officials seized 30 unlicensed rickshaws.

Because such transport often lacks catalytic converters and is poorly maintained, lightweight two-stroke gasoline-powered three-wheelers (also known as tuk-tuks and tricycles) cough up roughly 13 times more lung-damaging particulates than other engine types. Such soot kills across Asia—both ending and shortening the lives of those most exposed.

But three-wheelers are a valuable cog in the sustainable transit chain: Provided older makes go green, according to a new analysis from Embarq, the transit unit of the World Resources Institute, an environmental group. Their merits include affordability, maneuverability in snarled cities—after accidents they often serve as ambulances—and accessibility for the disabled, elderly and women. Most important, their role thwarting auto use as "last mile" feeders by ferrying multiple passengers helps improve the planet's health by curbing greenhouse gas emissions.

View a slide show of rickshaws today and cleaner alternatives

For example, because rickshaws have less mass and smaller engines, their CO2 emissions are about one third those of private cars, the latter of which consequently contribute as much as 90 percent of India's total urban road passenger transport emissions. Moreover, "Since [rickshaws] wear out the road much less and use less materials in construction and operation, their contribution to global warming will be much less than that of a heavier car," explains Dinesh Mohan, a transportation expert at the Indian Institute of Technology Delhi.

Today, rickshaws make up 20 percent of urban trips in India but comprise less than 11 percent of all vehicles because they are shared by multiple riders. So what can be done to make the rickshaw cleaner? Several things, as it turns out.

Cleaning the air
Because air quality in half of India's cities suffers from particulate pollution 1.5 times global standards, a shift to greener rickshaws could help dent emissions there sizably. Despite nationwide car ownership predicted to soar 40-fold by 2050, rickshaw production in India doubled between 2003 and 2010 thanks to growing affluence and urbanization.

This growth suggests that the rickshaw could also play a similar emissions-cutting role elsewhere with better engine and communications technologies like Global Positioning System and cell-phones. Suburban Delhi's Radio Tuk Tuk, for example, is popular for its "dial-a-rickshaw" four-stroke fleet. So are electric tuk-tuks and pedicabs in Bangkok and Kathmandu.

"Regulatory reforms, technology, finance and operational improvements can help entrepreneurs scale up, so that cleaner rickshaws meet their full environmental and economic potential," says Embarq's Akshay Mani, the report's lead author. Embarq's rickshaw framework argues for "avoid-shift-improve" principles: avoid unnecessary trips, shift to more sustainable modes and improve performance in all modes—through policy, services and technology.

"If you want cleaner [three-wheelers], you have to introduce new technologies and eliminate polluting rickshaws," explains Sophie Punte, executive director of the Clean Air Initiative for Asian Cities, from Manila.

But scrapping older models isn't easy. Today, five million rickshaws ply India's streets with roughly 80 percent of these iconic open-air taxis still boasting two-stroke engines in midsize cities such as Pune, Rajkot and Surat; many of the rest either run on two-stroke compressed natural gas (CNG) engines or the larger and cleaner-burning four-stroke gasoline or CNG engines.

14 Comments

1. 1. doctordawg 09:39 PM 4/7/12

   Why don't they make human powered city rickshaws with pedals in the back, too? I know with the driver and both my wife and I pedaling in the back, we could easily keep up with these two cycle menaces.
   
   Couple a battery/motor assist that's charged by regenerative braking to this planet-saver, and you've got a real solution.

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2. 2. huichang 10:41 PM 4/7/12

   althought the auto-rickshaw is very convenient for urban people,it is a mess for government to deal with the trafic problem.an transport system running under regulations is worth more consideration.
   

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3. 3. singing flea in reply to doctordawg 02:56 PM 4/8/12

   A- Americans don't want to wait for a tuk-tuk.
   B- Americans are concerned more about peer image then conservation.
   C- Americans can't drink and smoke in public transportation vehicles.
   D- Carrying groceries farther then the carport of garage to the kitchen door is against the law in some gated communities.
   E- Sharing space with stranger is as abhorrent as sharing a bag of french fries for the average American.
   F- Everyone in America that owns a SUV will tell you that a tuk-tuk with five people on board is far more polluting then a vehicle getting 18 miles to the gallon empty and heading down wind.
   G- Americans would rather pay to park and walk to shop then get dropped off at the front door and risk being seen buy their friends or co-workers.
   
   I could go one to the latter half of the alphabet, but I am sure most people will get the picture by now.
   
   If tuk-tuks were electric powered, offered air conditioning and scantily clad hostesses serving free cocktails and lunch, Americans still wouldn't give up their gas guzzlers.

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4. 4. alan6302 04:31 PM 4/9/12

   although the new engines appear "cleaner" . The emissions of nanoparticles have increased. That makes them more genetically / cardiovascular dangerous.

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5. 5. jgrosay 06:02 PM 4/9/12

   There are many alternative engines for that kind of vehicles, and also exhaust emission reducing catalyzers have greatly reduced its cost, but in the general field of this tiny transport means, an issue remains open to me: Am I right in thinking that human traction was long ago considered an unnacceptable way of anything but taking yourself?. Salut +

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6. 6. jgrosay 06:03 PM 4/9/12

   Two-stroke engines are just dirty oddities, good for nothing but industrial archeology museums.

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7. 7. jerryd 11:46 PM 4/9/12

   
   I drive a Trike the same size, power, speed except I use EV drive from a golf cart hot rodded with larger tires, higher voltage battery pack.
   
   Such a vehicle would do this service extremely well at 20% to run vs a gas, NG vehicle.
   
   While 4 strokes are better than 2 strokes they still pollute fairly bad in taxi service and still such gas which is $5-10/gal in these countries. Unlikely most are getting over 50 mpg which would cost $.50 in electricity and $.25 in battery. Prices are an average guess but likely close.
   
   So saving $4.50 or more/day quickly pays for the conversion which is rather simple though about $1500 so would be paid for in fuel savings in just a yr.
   
   Fast charging stations can be cheaply set up to charge them to 80% in just 15 minutes for $.50 and can profitably use solar PV now their price has dropped so much and the price doesn't have to ever go up if the taxi owners own the charge station. The above and new light EV's are buy far the most profitable and least poluting they can get.
   
   BTW 2 strokes can be clean but expensive needing direct injection and other goodies. But even if clean they still cost big time at the pump.

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8. 8. jerryd 12:12 AM 4/10/12

   
   I forgot EV's are far better accelerating with 3x's the torque of an ICE or more. I tow a 13' trailer filled with plywood and 2x4's, 4x4's, etc.
   
   I guess I should mention too mine is made of plywood and epoxy giving a very light and strong chassis that holds the batteries and the suspension bolts to. It's set up as a pickup, 3x4 bed with a trailer hitch for larger loads.
   
   It uses a MC ot moped front end and can go up to 50mph. With a car diff and bigger motor you can get most any speed you want though it better be aero if you want range at speed.
   
   It costs me $2/wk for everything, fuel, battery, tires, tag which is my biggest expense. It gets 33wthrs/mile means a kwhr gets me 30 miles/kwhr and a Kwhr costs me the US average of $.10kwhr. So for $1 of electricity I get 300 miles.
   
   For the price of 1 US gal of gasoline I can go 1200 miles now the price is $4/gal.

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9. 9. sanjaybhatt05 06:13 AM 4/10/12

   Can the 'experts' please elaborate.
   Is the comparison between car and rickshaw done with same fuel.
   Cars are having four stroke engines and are (petrol,diesel) based
   
   CNG based auto rickshaws nowadays are having 4-stroke engine. But the old rickshaws were having 2-stroke engines.
   Many car owners also fit CNG/LPG kits in the cars.
   So is the comparison by 'experts' done only considering Liquid fuel based cars?

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10. 10. kiteman 07:36 AM 4/11/12

    What about kite powered rickshaws? Only joking! Has anyone realised that particulates are carbon, that has not been combined with oxygen, to make CO2. So, why not capture the particulates either Dyson style centrifugal action, or by passing the exhaust through water?

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11. 11. jrvz 04:24 AM 4/12/12

    pokerplay hits the nail squarely on the head. The root cause of many of the worlds problems is overpopulation, and the worlds population is increasing every day.
    
    singingflea has got it exactly right. Most Americans don't give a rats backside about the rest of the world, or about environmental pollution, and many of them don't even know where the rest of the world is.

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12. 12. jrvz 04:54 AM 4/12/12

    Since the major problem with the Tuk-Tuks is the two stroke engine it would be possible to make a four stroke engine which could be a "drop in" replacement for the four stroke engine.
    
    Also since the major problem with the two stroke engine is the "total loss" lubrication system (oil is added to the fuel to lubricate the engine) it is possible to build a two stroke engine using fuel injection and to replace the crankcase compression system of delivering air to the cylinder. This could theoretically be better than a four stroke engine as there would be a power stroke every revolution instead of a power stroke taking two revolutions as in the four stroke engine.

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13. 13. jgrosay in reply to jrvz 04:55 AM 4/12/12

    You say "the root cause of many of the world's problems is overpopulation, and the world's population is increasing everyday". As you are free, you can add to the solution of what you think is the cause of exhaust gas emissions from obsolete technologies in developing countries: refrain from reproducing and add to the world no more offspring from you right now. For this you'll need a full sexual abstinence, as there's no 100% efficacious approach to family planning. Salut +

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14. 14. Beaver 05:40 PM 4/12/12

    I also agree that ICEs are not the future, but it may be with us for another 20 to 50 years. We should not forget that electric car is only as clean as the source of electricity. Generating electricity from coal and powering the present time obese and aerodynamically poor vehicles, - makes no sense at all.
    Once we start to produce electricity from clean and renewable sources, and batteries attain the power/energy density comparable to liquid fuels, obviously the choice will be electric. So far it is a shift from oil and gas... to coal. And that is not clearly explained to consumers... That is too bad.
    

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