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Air quality and GHG emissions

Informal Public Transport vehicles consume large quantities of fuel, predominantly diesel. When viewed over these vehicles’ long working lives, IPT vehicles in African cities produce significant volumes of airborne emissions both daily and cumulatively. This is not only a problem in terms of transport-sector greenhouse gas (GHG) emissions, as it also negatively impacts the quality of air that passengers, vehicles crews and those on and near roads breathe. Addressing these issues in the short to medium term does not necessarily require replacing vehicles or electrifying IPT fleets – lowering IPT fuel consumption will directly reduce emissions. There are multiple ways to do so, which include changing driver behaviour, improving vehicle maintenance practices, and providing dedicated infrastructure that increase vehicle operational efficiency.

Electric Charging Station


It is a complex matter to understand the current extent of IPT’s contribution to GHG and air quality issues. Not only is data needed on the actual and relative size of a city’s IPT fleet compared to the overall motorised vehicle fleet, but it is also important to know from where IPT vehicles are sourced, what type and quality of fuel is available and where this fuel comes from. Information on the quality and emissions controls that are in place for vehicles and fuel and is also beneficial. In addition, day-to-day operational insights are also needed in terms of driver behaviour, fuel purchasing practices, actual fuel consumption, the distances that vehicles cover, and how old a vehicle is. This information enables quantification of local emissions and related health and healthcare impacts. While there is little published research on such local operating characteristics and studies of local air quality and resulting health issues, there is some high-level data on vehicle and fuel supply.

Outside of South Africa, all vehicles used in the IPT sector in Africa are used imports, predominantly sourced from or via the European Union, and from Japan directly or via the United Arab Emirates. Local importation restrictions in terms of maximum vehicle age, roadworthiness and engine emissions standards do exist to varying degrees in Ghana, Mozambique and Sierra Leone, but there is some variance in the condition of each vehicle that ultimately is imported for use in the IPT sector. By contrast, South Africa has an established vehicle manufacturing sector, and in order to protect the new vehicle market that results, no used vehicle imports are allowed in this country. The predominant model used in the IPT sector is manufactured locally, and, aided by a government scrapping subsidy, the IPT vehicle fleet is comparatively new.

In relation to fuel supply and related fuel quality controls, there is yet again a distinction between South Africa and elsewhere in Africa. The former’s vehicle manufacturing base allows for more direct fuel type and emissions control, as vehicles are locally produced and fuels locally refined as opposed to both being dependent on importation. Environmental emissions regulation is comparatively very weak outside South Africa. This is primarily due to this country’s ban on used vehicle imports, as well as fuel quality standards that have been in place for many years (especially in terms of the sulphur content allowed in diesel). It should, however, be noted that Ghana has been strenthening its fuel quality controls with a similar aim in recent years.

While the above vehicle- and fuel-related interventions contribute to reducing emissions for, and health impacts of, national vehicle fleets, and thus in turn for IPT vehicles, the only public sector policy that overtly targets emissions-related responses for IPT can be found in South Africa. This is the national Green Transport Strategy released in 2018[19]. At a high level, this document notes the importance of reducing airborne pollutants from the transport sector to mitigate effects on public health and healthcare costs. In relation to IPT, the strategy proposes a process of engagement between government, operators and finance organisations to encourage a shift to cleaner fuels by converting minibuses to run on compressed natural gas.

Comparison of situations and perspectives from the TRANSITIONS cities

Informal Public Transport vehicles in the TRANSITIONS cities all see hard use. When not idling or crawling along in traffic, drivers try to get their next load of passengers as quickly as possible by driving aggressively and speeding back to the start of a route. Not only are such vehicles usually fully loaded with passengers, but they also accumulate significant mileages in the course of a working week. Aged, hard-working fleets, coupled with limited maintenance and a reliance on low-quality diesel, mean that IPT is a major contributor to greenhouse gas (GHG) emissions, as well as to local air quality and health impacts.

In Accra, it was found that, though IPT vehicles were imported from the used market, they were generally in a good condition at the time of importation. All these vehicles were diesel Mercedes-Benz Sprinter cargo vans that were converted for the carriage of passengers, with a typical age of 15 years at the time the research was conducted. Logging the total mileage or actual fuel consumption of each vehicle was difficult as most vehicles’ odometers were not in working order, though drivers reported purchasing in the range of 12-40 litres of fuel per day. GPS data showed that vehicles typically covered in the range of 150-170km per day, and were actively working for 2.6-9.7 hours. Average operating speed was 20km/h, though in dense traffic this could drop to 10km/h.

All 30 vehicles involved in the research in Cape Town were diesel Toyota Quantum minibuses. This model, also known as the Hiace in some markets, was also available in a less popular petrol variant, though few of these were in use by the IPT association. Reported first dates of vehicle registration were between 2015 and 2022. Daily operating distances ranged from 196km to 340km, over a working day of between 1.5 to 13.3 hours while travelling at average speeds of 25-75km/h (the latter possible along a freeway in the contra-peak direction). Though the digital fuel consumption installations did not work, odometers were all in working order. Drivers reported fuel purchases of 13-45 litres per day, and typical fuel consumption was calculated to be in the range of 26-43L/100km – a stark contrast to the manufacturer figure of 9.9L/100km.

At least six different minibus models were found in use in the IPT sector in Freetown, though the most popular model was the same as in Accra, the Mercedes-Benz Sprinter. Their ages were difficult to establish as they were imported through informal channels, and may also have changed owners after landing in the country. The tracked vehicles on average covered daily distances of 21-219km with a working day of a few minutes up to just over an hour, indicating average travel speeds of 7-22km/h. The calculated fuel consumption across the 19 tracked vehicles was in quite a narrow range – between 12.1 and 14.0L/100km, against official figures of 8.0-12.1L/100km. Average daily volume of fuel used was 3L to 27L.

As in Freetown, the IPT fleet in Kumasi consists of several different models, with seven noted in the research fleet. Their ages were estimated to be between 15 and 25 years, but as they were imported as used, exact figures could not be established. Average distances travelled per day were between 17km and 204km, with most vehicles covering well over 100km per day. Vehicles were active for 2-13 hours per day on average, with daily mean travel speeds of between 17 and 24km/h. Only one of the fuel probe installations worked for the entire week of tracking and thus actual fuel used and fuel consumption across the tracked fleet could not be calculated. On this one vehicle, reported daily refuelling volume was 17.5-43L.

The predominant IPT vehicle in use in Maputo was a diesel Toyota Hiace minibus, with smaller numbers of three other diesel models with either 15 or 26 seats. All were imported used from Japan, and were represented in the research. The majority of the tracked fleet was manufactured between 1995 and 2005. Both the fuel sensor and GPS installations proved problematic, which was in part overcome by supplementary manual data collection. This combined method revealed that, on average, vehicles covered 144-252km per day. Daily fuel volume purchased was between 27L and 52L. Fuel consumption was calculated in the range 15.3-18.1L/100km for the 15-seater models, compared to official figures of 5.5-6.3L/100km. Consumption for the two tracked 26-seaters was 34 and 34.5L/100km respectively, in contrast with official figures of 13-14L/100km.

Main findings and messages

Direct air quality impacts and GHG emissions from IPT vehicles can be calculated if these vehicles’ fuel type and consumption are known. While the overwhelming majority of IPT vehicles in the TRANSITIONS cities used diesel, in none of the case cities was there an existing database on the distances that vehicles covered, the speeds at which they travelled, or how much fuel was purchased. Neither government agencies nor IPT vehicle drivers and owners kept records of such data.

Measuring direct airborne emissions at each vehicle’s tailpipe was not viable. The equipment would have had to be imported from outside Africa, at significantly increased costs in comparison to the fuel probe (installed in fuel tanks) allowed for in this project. Given the wide range in condition and age of IPT vehicles in the case cities, the different operating conditions tied to the quality of infrastructure and traffic, and the consequent variations in fuel consumption this would bring, a large sample would have needed to be included for the results to be meaningful for estimating air quality impacts at the city level.

TRANSITIONS therefore focussed on gathering fuel and related operational data through the installation of digital GPS trackers and fuel consumption measurement equipment. The success of these installations varied, with issues encountered including procurement challenges, difficult installation procedures, malfunctioning sensors, and malfunctioning communications between such sensors and the data interface systems. Overall it appeared that equipment or service providers did not have tried-and-tested products ready to use in an IPT setting. It was, therefore, necessary to resort to manual tracking of distances covered and fuel purchased or consumed over successive days to calculate actual consumption. Such manual data collection processes also brought challenges, which included securing drivers’ or owner collectives’ participation, non-working or non-existent vehicle odometers, and reporting errors that were difficult to trace or correct. It was also labour-intensive to undertake such manual surveys, meaning that the resulting samples were small, even if they did yield greater results than what was possible through digital means.

From the TRANSITIONS findings, it was clear that in all cities the actual fuel consumption was notably greater than vehicle manufacturers’ claims. For example, in Freetown, fuel consumption was found to be 15-50% greater than claimed figures, while in Maputo and Cape Town consumption results were double, three times, or more, compared to manufacturer claims. This does not only confirm that fuel consumption claims are unrealistic, but also highlight the impact that IPT operating and vehicle conditions have on actual volume of fuel consumed.

It appears counterintuitive that in Cape Town, where the IPT fleet was the most modern of all the TRANSITIONS case cities, the highest fuel consumption figures were found. In this city, vehicles from one of the monitored ranks operated a ±35km-long route on an freeway, typically spending much of their time in low gears with aggresive cut-and-thrust driving and full passengers loads in the highly congested peak traffic direction. In the other, uncongested return direction, IPT vehicles travel at high speed, at times in excess of the national freeway speed limit of 120km/h. Both these behaviours would incur substantial fuel consumption penalties, and in the return direction such speeds are only possible in Cape Town as it is the only of the case cities with freeway infrastructure. This highlights the importance of understanding actual fuel consumption in the context of local operating conditions and the driver behaviour that such conditions produce.


Explaining fuel consumption outliers, or overall elevated consumption, was less clear-cut for the other case rank in Cape Town from which feeder-distributor IPT services operated. Since drivers self-reported daily fuel purchases (and in the absence of automated fuel tracking equipment) it was not possible to verify the accuracy of what drivers reported. It is possible that fuel costs might at times be deliberately over-reported, so that drivers could motivate owners to reduce the daily vehicle rental (target) amount due and thus end up with more take-home pay. This not only applies to Cape Town, but also in the other TRANSITIONS case cities where the target system is common. Moreover, this explanation for fuel spend over-reporting is speculative, but nonetheless indicates the need for the development of workable electronic fuel consumption measurement techniques. 

Even allowing for outliers and over-reporting, the increased actual versus on-paper (manufacturers’ specifications) fuel consumption found in the field in all TRANSITIONS case cities, translates directly to greater airborne pollutant and GHG emissions – and by extension to health issues - than what is typcially published. According to the Ecoscore tool[i], when combusted, one litre of diesel translates to 2640g of CO2. If the lowest consumption of 15.3L/100km in Maputo were used, it would translate into 404gCO2/km. Typical lower-order consumption in Cape Town was 26L/100km, equivalent to 686gCO2/km. These figures are of great concern if compared with the EU upper limit target for vans in the period 2020-2024 of 147gCO2/km – less than half of even the lowest figures calculated  from the lowest figure that TRANSITIONS found in Freetown, being 319gCO2/km (calculated from 12.1L/100km).

The absence of policies in the TRANSITIONS cities to address emissions from IPT was mirrored in the relatively few instances where interviewed stakeholders reported that such emissions were of concern. More problematically, there were no current actions to reduce fuel consumption in the IPT sector, though cleaner fuel standards, roadworthiness requirements and vehicle import age limitations were in place or being introduced in most of these countries no doubt played a role to reduce emissions to some extent, whether directly or indirectly. It is important to note that issues related to vehicle and fuel supply are subject to national and international supply chains and cooperation between multiple public and private stakehoders, and thus are complex matters to address.

From a vehicle supply point of view, South Africa’s protected new vehicles market has provided a distinct advantage over the other TRANSITIONS countries, though it likely came at cost in terms of higher prices that IPT owners paid for their vehicles. These prices, in turn, stimulated a large vehicle finance industry. It can be argued that such finance made it possible to have newer fleets, but at the same, if the levied interest rates were high – as they were found to be – operators could be left short-changed.

It was clear from the TRANSITIONS fuel surveys that IPT operators purchase large volumes of fuel on a daily basis. Indeed, in Cape Town, for example, fuel purchases make up the single largest IPT business cost, even if some allowance is made for some degree of over-reporting. In this city, drivers usually have to pay for fuel (and vehicle rental) out of fare revenue before they have a take-home income. Reducing fuel consumption would directly reduce their fuel expenditure, improving drivers’ livelihood prospects. It is likely that such an economic argument would have more traction in the IPT sector than would environmental or societal good arguments. Further information for a discussion of potential measures that could contribute to achieving these aims can be found here.



19. National Department of Transport, 2018. Green Transport Strategy for South Africa (2018-2050)

20. Ecoscore Tool, 2022. How to calculate the CO2 emissions from fuel consumption -

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