Chapter 7.3, Problem 117E

To determine

To work: an extended application analyzing the fuel economies of cars from 1998 through 2017.

Explanation of Solution

Global average fuel consumption of new cars sold in 2017 improved only 0.7% year-on-year, slowing from the average 2005-16 improvement rate of 1.85% per year. To get on track with the SDS, which is aligned with the 2030 GFEI targets, annual improvements of 3.7% are needed. It is vital that standards become significantly more stringent and that vehicles comply with them in real-world driving conditions. Ambitious but achievable CO2 standards passed by the European Union and stricter standards in China inspire confidence, and rapid EV adoption will also help achieve efficiency goals.

Fuel consumption is most intuitively measured as the fuel required to travel a unit of distance (L/100km). Another common metric is fuel economy, which is the inverse of fuel consumption, or the distance travelled per one unit of fuel (e.g. km/L or MPG). This metric is calculated for each vehicle model through standardized testing procedures and drive cycles. Technologies that improve vehicle fuel efficiency are important for CO₂ emission reductions because they enable the emission of less CO₂ for the same amount of transport activity.

There is much regional divergence in recent trends for average sales-weighted fuel consumption of newly sold LDVs. In the United States, average fuel consumption in 2018 had improved 0.8% from the previous year, reaching 9.4 L/100 km (according to the five-cycle EPA test), and preliminary figures indicate a further improvement of 1.6% in 2019.

In Europe, after 16 years of continuous improvement, fuel consumption worsened in 2017 and 2018, with estimates indicating it had risen to 5.1 L/100 km in 2018 (NEDC test). While no European data are available for 2019, powertrain sales shares at least suggest that fuel consumption did not continue to rise from 2018 to 2019. 

The worldwide market share of SUVs rose 15 percentage points between 2014 and 2019, to make up 40% of the global LDV market. Shares in North America and Australia were particularly high, around 50%. In addition to SUVs, pickup trucks − which tend to be even larger − also make up a significant share of sales in these markets.

Markets that traditionally have smaller vehicles, such as Europe and Japan, have also joined this global trend: in Europe 38% of new vehicles are SUVs, compared with 10% in 2010. The greatest market share growth has been in the small SUV segment, which includes many crossover versions of popular passenger cars. The average fuel consumption of a small SUV/pickup is more than 15% higher than for an average medium-sized car, for which market shares have fallen the most in recent years.

While most new vehicle sales are covered by fuel economy regulations, there is still scope for some countries − especially in the developing world − to introduce fuel economy standards, as the ASEAN countries have done recently. These regulatory tools have been proven effective to introduce better engine and vehicle technologies into the market and to decrease fuel consumption, and they are needed now to put the world on track with the SDS goals. Furthermore, implementing fuel economy regulations would prevent developing countries from becoming dumping grounds for outdated vehicle technologies that are becoming uncompetitive or prohibited in their home markets.

As the Diesel gate scandal so vividly demonstrated, it is possible for car manufacturers to comply with testing requirements even while selling vehicles that emit pollutants with serious health impacts in real-world driving conditions. The same applies to CO2 emissions, but there are ways to improve regulatory procedures to avoid this, as demonstrated by efforts to: (a) devise a more representative testing procedure that incorporates real-world driving emissions (the WLTP); and (b) monitor in-use emissions of local air pollutants (The Real Urban Emissions (TRUE) initiative). These systems must be scaled up and adopted by more countries, however, and always at the national level.