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Motorised three-wheeler taxis

This article presents readers with the option of retaining three-wheeler taxis – with attention to better technology, maintenance and regulation – on the grounds that they perform a valuable role in the localities where they exist, and if they were removed the vehicles and travel practices that replaced them would produce increased congestion, road injuries and fatalities, air pollution and greenhouse gas (GHG) emissions. On these grounds, localities that do not have three-wheeler taxis might even consider introducing newer, cleaner-technology versions of them.

Introduction top

In certain parts of the world, most notably South Asia, small motorised three-wheeled passenger taxis are a significant component of the urban transport system. Besides South Asia, three-wheeler taxis are also common in Indonesia, Thailand, coastal Kenya, Ethiopia, and increasingly Tanzania, Egypt, the Gambia, Cambodia, Laos, Philippines, Cuba, Guatemala and Peru, with small numbers in the Netherlands and Britain. In certain places, especially parts of Southeast Asia and East Africa, motorcycles – sometimes with a side-car or trailer – are also used as taxis. Three-wheeler taxis have a variety of names in different countries, including auto-rickshaws, tuk-tuks, trishaws, autos, rickshaws, autoricks, bajajs, ricks, tricycles, mototaxis and baby taxis.

These vehicles are often seen as a problem, as a source of unacceptable air pollution with their twostroke engines, and as a cause of traffic congestion, given their slow speeds and the stops they make to pick up or to drop off passengers, or to wait for new customers. In some cities and countries there has been discussion of banning them, and in some places they have been banned, like in central Mumbai.

In most cities three-wheeled taxis constitute only a small proportion of motorised travel. Even in India they generally account for no more than five percent of passenger travel (Bose et al., 2001), although their role may be bigger in certain towns, and they may make up a large proportion of the traffic within busy commercial areas. However, when it comes to reducing GHG emissions, local pollution and other problems associated with transport, even small proportions matter. Transport systems consist of many different kinds of vehicles, technologies and practices, but these all need to be addressed if the necessary overall improvements are to be achieved.

Feasibility of technology and operational necessities top

Conversions of three-wheelers to CNG and to LPG are well established for three-wheelers (but not feasible for two-wheelers). For example, tuk-tuks in Bangkok have been operating on LPG for many years. Delhi’s CNG conversion is said to be operating satisfactorily and other Indian cities are following this now. CNG auto-rickshaws have rapidly become the norm in Bangladesh, Indonesia and Pakistan, countries where CNG prices are subsidised and therefore low. But a policy of subsidising fossil fuels – even those fossil fuels that are cleaner than others – is questionable. Shifts in the vehicle population from twostroke to four-stroke have proceeded smoothly in many countries, a shift often accelerated by tightening emissions standards (Shah and Iyer, 2002).

illustration ©

Figure 1: The traffic on this street would be much less congested and produce much less pollution and greenhouse gas if there were fewer cars, and instead improved, cleaner technology auto-rickshaws delivered passengers to bus and train services (picture credit: Shyaulis Andrjus).

The place of three-wheeler taxis in the overall transport system

There is often concern about the impact of three-wheeler taxis on traffic flows and congestion, given their low-speeds and the fact that they are often stationary while waiting for passengers or while picking them up or dropping them off. Such concerns often lead to restrictions on their numbers and even calls for them to be banned altogether. It is claimed not only that they increase congestion, but also that this increased congestion increases GHG emissions. However, there are three problems with this line of argument.

Firstly, expectations of smoothly flowing traffic are likely to be illusory or short-lived, because the improved traffic flow encourages more people to drive and own vehicles, which means that the congestion rapidly returns.

Secondly, if three-wheelers are restricted or taken off the road the passenger demand that they once catered for is likely to be satisfied in two other ways: by an increasing number of four-wheeled taxis, and by increasing purchases of private vehicles (either cars, motorbikes or motor cycles). Looking first at four-wheeled taxis, these have much higher air pollutant and GHG emissions than do three-wheelers (depending on the size of the four wheeler, as four stroke engines are more efficient than two strokes but only if in a similar sized vehicle), and they take up more area and therefore contribute more to congestion.

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Figure 2: People often associate auto-rickshaws with congestion, as in this photo, but imagine how much worse the congestion would be if these were all car-sized taxis.

If, on the other hand, households buy their own car or two-wheeler because fewer taxis are available, especially cheaper three-wheeler taxis, then their mobility patterns are likely to change drastically. Partly out of habit and partly to justify their major purchase, they will tend to ignore other transport modes and solely or predominantly use their private vehicle. Of course, if that vehicle is a car, it also produces more GHG emissions than a three-wheeler taxi does. If it is a motor cycle, it may generate as much local air pollution as an unimproved three-wheeler taxi.

Thirdly, restricting the number of three-wheeler taxis can raise the cost of operating licences, because such licences become a scarce commodity in great demand. This creates a risk of corruption and the involvement of organised crime in the industry. Furthermore, when drivers face a cost squeeze their on-road behavior often deteriorates, as seen for example in Delhi compared with other Indian cities (Mohan & Roy, 2003). Singapore, on the other hand, abolished quantity limits on four-wheel taxis, a measure which, combined with effective regulation of quality, has improved taxi service and kept costs low.

Thus, it is probably a bad idea to restrict or ban three-wheeler taxis. Nevertheless, it does seem plausible that a program of providing convenient and well-designed waiting ranks for three-wheeler taxis could reduce GHG emissions and reduce fuel consumption by reducing empty cruising for fares, and by reducing the traffic disruption arising from ad hoc waiting and stopping. Auto-rickshaw operators in Delhi for example are reported to be forced to do significant cruising without passengers due to an absence of stands and prohibitions on parking (Mohan & Roy, 2003). Improved waiting places may also help reduce disruption to buses and non-motorised vehicles.

An added benefit of three-wheeler taxis is that they are especially suited to playing a feeder role for mass transit. As cities improve their main trunk transit facilities, they often face a period in which ordinary bus systems are not yet well integrated with the newer high-speed, high-capacity systems, whether MRT, LRT or BRT. However, low-cost taxis such as three-wheelers can fill this ‘last kilometre’ gap, along with motorcycle taxis, private motorcycles, non-motorised pedicabs and bicycles.

This section has argued that small taxis, such as three-wheelers, can be a positive factor in a city’s transport system. However, more policy effort will be needed in most countries to achieve regulatory arrangements and industry structures to better foster a healthy, efficient industry with lower emissions and with better conditions for both passengers and drivers.

Status of the technology and its future market potential top

In places where small taxis are common, it is extremely important and urgent to reduce their local air pollution impacts (together with those of private motorcycles). Considerable policy effort has therefore focused on reducing these emissions. Policies and programs to reduce local air pollution often also reduce GHG emissions.

Until quite recently, most three-wheelers and motorcycles in developing countries have had two-stroke petrol engines, in which lubricating oil is mixed with the fuel and burns with it. Such engines have contributed significantly to unhealthy local air pollution. In Delhi in the late 1990s, for example, almost half of particulate emissions and two-thirds of unburned hydrocarbon emissions from transport were attributed to two- and three-wheelers, with each such vehicle emitting almost as much fine particulate matter as a light diesel truck (Gwilliam, 2003). In several countries, very low-octane fuels, adulteration with subsidised kerosene and over-use of lubricant in the fuel mix further multiplies the unhealthy smoke produced by two-strokes, and reduces their fuel efficiency (Kojima et al., 2000).

Technological interventions for small taxis have focused especially on conversions to CNG or LPG (via retrofits or with new purpose-designed vehicles), and on shifts to four-stroke engines and to engines with modern fuel injection. A small number of projects have introduced hybrid or fully electric three-wheelers (as discussed later). Maintenance and inspection programs are another important aspect of tackling noxious pollution from these vehicles, and these tend to improve fuel economy and reduce GHG emissions.

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Figure 3: There are two types of 'bajaj' threewheeler taxis in Jakarta: the orange ones with a two-stroke engine and the blue ones with a CNG engine.

Opinion is divided on the prospects for shifting three-wheeler taxi fleets to electric operation. Most commentators argue that the costs remain too high for adoption on a scale large enough to make a significant difference to GHG emissions (Kojima et al., 2000). However, electric vehicles are an arena of rapid technological change and this judgment may need to be reviewed often. Small-scale electric three-wheeler taxi projects are emerging in areas such as in Bangkok, and in Agra, where the Taj Mahal is located and polluting vehicles are thus forbidden. Electric vehicle projects seem to be most compelling in contexts where local pollution reductions are urgently needed and politically well-supported. There can be significant GHG emission reductions from conversions to electric vehicles, but of course such benefits depend on the source of electricity.

An exception to the widespread caution over electric three-wheelers is the reaction to Kathmandu’s shift from diesel three-wheelers to electric ones in the late 1990s and early 2000s. Factors leading to this shift included:

  • a groundswell of concern about the pollution from old diesel vehicles
  • government policies that waived import taxes and annual fees for electric vehicles
  • the use of cheaper off-peak electricity for recharging
  • a ban on diesel powered three-wheelers, which eliminated the competition (Dhakal, 2003).

Although this project was not motivated by climate change considerations, the GHG reductions in this case are much higher than would be the case in most countries because Nepal’s electricity supply is mainly hydroelectric. It has proved difficult to replicate this success elsewhere in South Asia, except in certain circumstances such as the Taj Mahal environs as just mentioned. These two examples do show, however, that given the will there can be rapid changeover to electric three-wheelers.

Hybrid electric three-wheeler taxis also have promise, with the possibility of 30% GHG emission reductions, but so far such vehicles have only been proposed.

Contribution of the technology to social development top

Cleaner vehicles lead to improved health and quality of life as pollution is reduced, while retention enables a range of urban services and locations to remain more accessible.

In many cities, the operators of small taxis are a vulnerable and powerless low-income group. Project implementation needs to be careful not to worsen their position. Better conditions and livelihoods for drivers can and must be one goal of regulatory and enforcement reforms aimed at raising the quality of the service provided by this industry.

Contribution of the technology to economic development (including energy market support) top

Cleaner vehicles have reduced fuel use and therefore lower running costs, as well as reduced health costs caused by pollution. However, the extent of these direct economic benefits depends on the extent to which lower running costs outweigh possibly higher up-front costs for the vehicles or their conversions. Some projects discussed below seem to meet this market-test criterion.

Retention of a flourishing small-vehicle taxi industry means there is a low-cost individualised transport alternative, including for those who do not own a private vehicle. This should have significant, although difficult-to-quantify economic benefits.

Contribution of the technology to protection of the environment top

Cleaner vehicles lead to reduced local pollution, greenhouse gases and noise, while retention of a successful small-vehicle taxi industry should lead to lower GHG emissions overall by helping to avert rises in the numbers and usage of vehicles with higher emissions.

Climate top

Although three-wheelers have fewer passengers and therefore higher emissions per passenger kilometre than well-used public transport, they produce far fewer GHG emissions than private cars or full-sized four-wheeled taxis. In India, GHG emissions per kilometre from auto-rickshaws are about a third of those from four-wheeled taxis or cars. Thus, in the context of all vehicles, they already have relatively low GHG emissions per passenger kilometre. At the same time, they provide individualised urban transport, often in very narrow thoroughfares, which mass transit cannot do, and they also complement mass transit by providing feeder transport to it. If three-wheeler taxis have a third the GHG emissions of full-sized cars or taxis, that means they can save 85-115 grams of CO2 equivalent GHG emissions for each passenger kilometre, assuming the same number of passengers in each vehicle. From a wider perspective, this estimate may actually be conservative. Although empty cruising by small taxis would worsen their average emissions per passenger kilometer, a vibrant taxi industry helps slow increases in ownership of private motor vehicles. Since vehicle ownership dramatically increases household vehicle kilometres and GHG emissions, slowing motorisation can avert a significant amount of emissions.

There is potential for these technological interventions to reduce greenhouse gas emissions. Taking account of various interventions, reductions in GHG emissions per km travelled of around 20% have been estimated in studies (Singh, 2006).

Projects to shift three-wheelers from petrol to CNG can reduce GHG emissions by about 20% per vehiclekilometre when the new vehicles are designed and manufactured to run on CNG, but retrofitted former gasoline vehicles can have higher GHG emissions than before (Bose et al., 2001). There is also a risk that natural gas may leak from poorly maintained re-fuelling and vehicle tanks, which would worsen GHG outcomes, since methane is a strong GHG.

Conversions to four-stroke engines offer significant air-pollution benefits, and reductions of about 10 to 15% as long as larger, heavier vehicles are not used. Conversion of carbureted two-stroke to directinjection appears to offer greater gains of up to a 30% improvement in fuel efficiency.

Poorly maintained vehicles are responsible for much pollution, and inspection and maintenance programs are a proven intervention to reduce this. Such programs are important in order to maintain emissions reductions over the life of each vehicle, especially for high-use commercial vehicles (Gwilliam, 2003). Without adequate maintenance the benefits of the other technology interventions can easily erode. Fuel economy and GHG emission reductions can be improved by up to 17% in the case of very poorly maintained vehicles.

Financial requirements and costs top

Diverse interventions have been mentioned so it is difficult to be specific about costs and sources of funds. Care must certainly be taken that mandated transitions to cleaner technology take account of costs imposed on the industry itself. Economists have argued that setting emissions standards would generally allow lower-cost compliance than mandating specific technologies. However, special circumstances (such as rampant adulteration of fuels) may sometimes modify this conclusion.

The most promising vehicle and fuel technology interventions are those which have a reasonable payback period, so that the upfront cost is recovered via lower operating costs. In such cases, technical assistance, regulatory nudges and accessible financing are likely to be more important than high levels of funding. In some case, fleet transitions have been market driven, although there are concerns that some of these have only been possible due to fuel subsidies that may prove unsustainable (such as for CNG in South Asia). There has also been debate about the cost-effectiveness of gas-powered three-wheelers, for example, CNG vehicles and their maintenance in Delhi, where CNG use has been mandated for auto-rickshaws and buses since 1999 (Mohan & Roy, 2003; Gwilliam, 2003).

For many of the technological interventions mentioned, GHG reductions are a co-benefit of projects that are justified on air pollution grounds. They may therefore attract funding associated with clean air priorities, at local, national or international levels, as well as funding targeting GHG reductions.

References top

Bose, R. et al. (2001). Transportation in Developing Countries: Greenhouse Gas Scenarios for Delhi, India.
Prepared for the Pew Center on Global Climate Change, May.

Dhakal, S. (2003). Role of Government, private sector and civic society in promoting battery operated electric three-wheelers
in Kathmandu, Nepal, Report for Institute for Global Environmental Strategies (IGES), Japan.

Gwilliam, K. (2003). ‘Urban transport in developing countries’, Transport Reviews, 23: 2. p 205,, viewed 20 Feb 2011.

Kojima, M., Brandon, C. & Shah, J. (2000). Improving Urban Air Quality in South Asia by Reducing Emissions from Two-Stroke Engine Vehicles, The World Bank, 2000,, viewed 20 Feb 2011.

Mohan, D. & Roy, D. (2003). ‘Operating on three wheels: auto-rickshaw drivers of Delhi’, Economic and Political Weekly, India, vol 38, no 3 (Jan 18-2), pp 177-180.

Shah, J. and Iyer, N.V. (2002). ‘Module 4c Two- and Three-Wheelers’, Sustainable Transport: A Sourcebook for Policy-makers
in Developing Countries, GTZ.

Singh, S.K. (2006). ‘Future mobility in India: Implications for energy demand and CO2 emission’, Transport Policy, 13, pp