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Environmental characteristics of the Brussels vehicle stock

With half a million cars, the Brussels vehicle stock is made up of two thirds private vehicles and one third company vehicles. Diesel cars represented 61% in 2014, bearing in mind that six out of ten are fitted with particle filters. After growth in the number of diesel vehicles over the last few decades, this segment of the vehicle stock has stabilised since 2011. The average Ecoscore of the stock was 57 in 2014. The score of the new car stock (representing 16% of the total stock) was 64. Both increase by around one point every year. The alternatives to conventional engines (diesel and petrol) are still marginal.

The Brussels vehicle stock in figures

In 2014, the Brussels vehicles stock amounted to almost 500,000 cars and represented almost 10% of the total Belgian vehicle stock (Direction pour l’immatriculation des véhicules (Vehicle Registration Directorate) (DIV) of the FPS Mobility and Transportation according to Ecoscore, as of 31 December 2014). Two thirds of the stock is made up of private vehicles, with the remaining third being company vehicles. In the same year, cars registered for the first time (i.e. new cars) represented 16% of the Brussels stock (and 9% of the Belgian stock); they all comply at least with the Euro 5 standard. Other vehicles entered into service (i.e. used cars) represent 11% of the stock. The number of new or used cars, which entered into service, decreased in 2014 as compared with 2011, for both diesel and petrol cars: this was a probable consequence of the economic crisis.

Between 2012 and 2014, there was however a very slight increase in the stock (+0.8%) due to a reduction in the number of de-registrations (FEBIAC, datadigest 2015). In reality, the increase of the vehicle stock corresponded to an increase in company cars and leasing cars. The stock of private cars remained stable. In this regard, it can be specified that around one Brussels household out of two has at least one car (56% in 2012 according to the survey into household budgets (EBM)), bearing in mind that this level is evolving downwards.

Two features of the Brussels vehicle stock related to company cars and commuters

Some features of the Brussels vehicle stock warrant attention here due to their influence on the analysis presented in this sheet:

  • Firstly, the share of company cars is higher here than elsewhere: 35% of the stock in 2014 (versus 15% for Belgium) and if we take into account new registrations, this becomes 82%. Of course, the headquarters of numerous companies are in Brussels territory. However, company cars differ from private cars in numerous respects and these differences have an impact on the environmental performance. Firstly, company cars are replaced on a regular basis and are therefore newer: given that Euro standards for new cars placed on the market have become more and more strict over the years, company cars - when compared with an equivalent model - tend to meet new standards more comprehensively. Secondly, they are subject to different tax rules, for which CO2 emissions represent an important factor. This incentive favours diesel engines, which emit less CO2 but more atmospheric pollutants. Thirdly, the image of the company plays a major role in the choice of vehicle (especially for those bought by the company): company cars tend to be models with larger engines and power, whose environmental impact is generally bigger compared to smaller and less powerful cars. Fourthly, the number of kilometres driven with a company car is much higher on average than with a private car: 9,200km extra per year according to a study by the Belgian Science Policy Office (BELSPO, PROMOCO study, 2009). Fifthly, since company cars are more sensitive to economic activity, the effects of a financial crisis are felt more strongly.
  • Furthermore, the place of registrations does not necessarily provide any information about the stock which circulates within a territory. This particularly holds true in the Brussels Region. Firstly, many company cars, although they are registered in the Brussels Region, do not circulate within the regional territory. Conversely, commuters coming to work in the Brussels region by car (50% of incoming commuters, according to BELDAM 2010; see also the sheet "Mobility and Transport") circulate within the regional territory even though their car is registered elsewhere. Taking into account the high numbers of both company cars and commuters, there is therefore a discrepancy between the vehicle stock registered in the Brussels Region and the cars actually circulating within it. This is why the majority of indicators provided in this sheet are not only given for the Brussels vehicle stock but also for the total Belgian stock.

The amount of diesel cars in the Brussels vehicle stock is stable

Diesel cars represent the largest share of the Brussels vehicle stock (61% in 2014), ahead of petrol cars (37%). Alternatives to conventional cars (hybrids, compressed natural gas (CNG), liquefied petroleum gas (LPG) and other technologies) only accounted for 2% of the stock in 2014.

6 diesel cars out of 10 (of the Brussels stock) are fitted with particle filters. It should be highlighted here that new diesel cars must obligatorily be fitted with these filters since 1 January 2011 (Euro 5 et seq.).

The share of diesel cars among new registrations (71%) exceeds that observed in the total Brussels stock.

Furthermore, an overwhelming majority of company cars are diesel-powered.
Whereas the proportion of diesel cars in the vehicle stock grew relentlessly over the last few decades, there has been a stabilising trend since 2011, also for new registrations (both new and used cars). However, the share of petrol in new private cars drastically increased between 2008 and 2014 (from 40% to 61%). This evolution is a good sign given that diesel engines pose several disadvantages within the Brussels urban context: firstly, short journeys which are typical in an urban environment (Brussels inhabitants drive their cars an average of 27km per day - FPS Mobility and Transportation, BELDAM survey 2011) cause this type of engine to wear out prematurely (it takes longer to achieve the optimum temperature) and the particle filter to clog more rapidly. And above all, diesel has a more negative environmental impact than other fuels, particularly on air quality, even though the Brussels Region is confronted by a major air pollution problem (NOx and PM) (for more detailed information, see the indicators on air quality).

A vehicle stock which is older than the Belgian stock, and continuing to age.

The average age of the Brussels vehicle stock in 2014 was 8.5 years (compared with 7.9 at the national level). This average age contrasts sharply depending on whether we consider company cars (2.8 years) or private cars (11.6 years). This is the logical consequence of company cars being renewed more often than private cars. But the Brussels stock differs from other vehicle stocks (regional and Belgian) by the age of its private vehicles (which are around 3 years older on average than the Belgian stock). Furthermore, the share of vehicles older than 25 years (7%) is larger (vs 4%). And the vehicle stock is ageing (phenomenon observed throughout Belgium).

The Ecoscore, a comprehensive indicator of the environmental performance of the vehicle stock

The Ecoscore is an indicator of the environmental performance of a vehicle. The result is a score on a scale from 0 to 100: the higher the Ecoscore, the less the car pollutes. The calculation method used takes into account both the emissions due to journeys made by the vehicle (exhaust emissions) and those due to the production and distribution of fuel or electricity. The impacts evaluated are the greenhouse gas effect, atmospheric pollution (affecting both health and ecosystems) and noise pollution. Specifically, the evaluation pertains to the emissions of three greenhouse gases (CO2, CH4 and N2O), five atmospheric pollutants (NOx, PM, SO2, CO and hydrocarbons (HC)) as well as the noise of the engine.

The Ecoscore has the advantage of providing a comprehensive evaluation of the environmental impact of a vehicle rather than merely CO2 emissions or Euro standards (see the methodological sheet).

However, the Ecoscore (just like the Euro standards) underestimates the actual emissions and fuel consumption of vehicles. One of the explanations for this observation is that the emissions are estimated based on the vehicle homologation test - the New European Driving Cycle (NEDC) -, which consists of a standardised test cycle performed on a test bench, which is not representative of real driving conditions (European Environment Agency, 2015). Furthermore, manufacturers can use techniques (authorised by legislation) to artificially reduce the official consumption of their car and its polluting emissions during this test (on this subject, see the article by Test-Achats from July 2015, referenced in the sources).

Emissions of CO2 are therefore 20 to 25% greater on average under real conditions than what is recorded during the homologation test (Ecoscore website, 2015).

It has also been found that the actual emissions of NOx from diesel cars significantly exceed those set by the Euro standards and these differences are accentuated depending on the Euro standard level (3.5 or 5 times greater according to Graz Technical University in Austria and the Joint Research Center (JRC) respectively for the Euro 5 standard; 7 times greater for the Euro 6 standard) (Ecoscore website, 2015).

In order to approximate actual conditions of use, Ecoscore does not use the homologation data for the NOx emissions of diesel vehicles: for these, Ecoscore take into account a constant emissions factor (that of the Euro 2 standard) for vehicles meeting Euro standards 0 to 5, and a slightly lower factor for vehicles meeting the Euro 6 standard.

The Ecoscore of the Brussels vehicle stock

The average Ecoscore of the Brussels vehicle stock was 57 in 2014, and 7 points higher for the stock of new cars (idem for the Belgian stock). Both increase by around one point every year.

If we take into account the total vehicle stock, company cars have a higher average Ecoscore (60) than private cars (56). This result may appear surprising given the fact that company cars are predominantly diesel-powered and diesel engines have a lower average Ecoscore than petrol engines (see below). In the case of new stock, we observe the opposite situation: company cars have a lower average Ecoscore (63) compared with private cars (67).

Evolution of the average Ecoscore of the Brussels vehicle stock (total and new) and per type of owner (2012-2014)
Source : Ecoscore Reports, 2014

The average Ecoscore according to the type of fuel indicates that petrol cars have a lower overall environmental impact than diesel cars (their average Ecoscore is 8 points higher: 62 compared with 54 in 2014) (see also the info-sheet concerning the inclusion of the Ecoscore in the purchase/leasing procedure for new vehicles). The Ecoscore increases every year (by around 1 point) for both types of engines. However the improvement is slightly more accentuated in the case of diesel cars, leading to a reduction in the difference with petrol. Compared to the Belgian stock, the Brussels stock has an Ecoscore which is one point lower for petrol vehicles and one point higher for diesel vehicles.

Hybrid petrol cars have an Ecoscore equivalent to vehicles powered by compressed natural gas (76). As for hybrid diesel vehicles, they represent an interesting alternative to conventional diesel vehicles, especially due to the "plug-in" system which approximates the performance of hybrid petrol vehicles. Vehicles powered by LPG have an Ecoscore similar to conventional petrol vehicles (60). The technology providing the lowest environmental impact is unsurprisingly electric vehicles with an Ecoscore of 86.

However, the good results of all the alternatives to conventional fuels need to be qualified, given that they only make up a minimal proportion in the total stock.

Other environmental performance indicators of the vehicle stock: CO2 emissions and EURO standards

The CO2 emissions of a car registered in the Brussels Region are 147 g/km on average (in other words, very close to the Belgian average: 149 g/km). These figures fall every year by almost 3%. Company cars emit on average significantly less CO2 than private vehicles (130 g/km vs 157 g/km) and the reduction of their CO2 emissions is more pronounced (-4% every year compared with -1 to -2%). As previously explained, this observation results from the more rapid renewal of this stock and the tax policy with regard to companies, which favours diesel engines.

Evolution of the distribution of EURO standards in the Brussels vehicle stock (2012-2014)
Source : Ecoscore, 2014

The date to the right of the EURO standard corresponds to the date of entry into force of the standard for the cars.

In 2014, Euro 5 represented the most common standard in the Brussels stock (42%), followed by Euro 4 (27%). Whereas just 2 years ago, the predominant standard was Euro 4. The evolution of the Brussels stock attests to the rapid progression of Euro 5, which replaced Euro 4. The Euro 6 standard (which has been obligatory for new cars since September 2015) still remains marginal.

Compared with the Belgian stock, the Brussels stock presents two particular features: the proportion of the most recent standards (Euro 5 and 6) is higher (45% versus 38% in Belgium) but the proportion of the oldest standard is higher too (Euro 0 - 8% versus 5%). The results confirm the double observation that the Brussels vehicle stock renews itself rapidly, but also includes a significant proportion of very old cars (old-timers).

A constant improvement in the environmental performance of the vehicle stock, but still with an ever-present mobility problem

The evolution of the Ecoscore of the Brussels vehicle stock confirms that environmental performance is improving. However, this positive assessment should be put in context by taking into account the overall impact of a car on the environment, including its impact on mobility: as efficient as they can be, cars actually create a congestion problem in terms of journeys and parking. Moreover,Brussels Region and Belgium are confronted by a clear mobility problem and several indicators suggest that the problem is not getting any better: an admittedly weak, but definite, growth in the vehicle stock; an increase in structural traffic jams (i.e. not caused by bad weather or accidents) in Belgium in 2014 (total length of traffic jams between 100 and 150km observed on 42 full days - Touring Mobilis Barometer, 2015). Nevertheless, other indicators suggest a positive evolution (cfr. sheet "Mobility and Transport"): decrease in road traffic (excluding the ring); sharp increase in journeys made by public transport and by bicycle; decrease in car use by Brussels inhabitants, in particular for "home to work" journeys.

Date de mise à jour: 26/10/2018


Methodological sheet(s)

Other publications from Brussels Environment

Study(ies) and report(s)

Plan(s) and programme(s)