**4. Understanding Di**ff**erences in Patterns of Energy Use in Swedish Cities**

This section addresses the third research question in the introduction which seeks to explain patterns of passenger transport energy use per capita in Swedish cities by reference to a set of standardized transport and land-use indicators developed for each city and compared to other global cities and Freiburg. Table 4 contains these data.

The preceding data have shown that Swedish cities have almost identical average per capita use of energy in both private and public transport systems, despite, as Table 4 shows, having densities which are significantly below those in other European cities (16.9 cf. 47.9 persons/ha) and notwithstanding that density has been shown to be the most strongly correlated variable in explaining urban energy use in private passenger transport [26,28]. This low energy use is, of course, linked to the fact that Swedish cities also have nearly identical car passenger kilometers (PKT) per capita as other European cities (6888 car PKT/person cf. 6817, respectively), which is at least partly explained by the Swedish cities' lower car occupancy of 1.31 compared to 1.38 in other European cities in 2005. Car passenger kilometers is the result of car vehicle kilometers multiplied by the average 24 h/7 days per week car occupancy, and of course includes the driver. Such low car occupancy and underutilized capacity in public transport due to low vehicle and seat occupancy (explained later) are naturally also sources of potential energy conservation if occupancies can be increased.

So, how might the relatively low car use per person and low private transport energy use per person, despite comparatively low urban densities in Swedish cities, be explained? A review of the data in Table 4 highlights some significant findings regarding Swedish cities which serve as mitigating factors in understanding the above issue. However, it is first important to highlight the metropolitan Gross Domestic Product (GDP) per capita factor in Table 4. It is common to hear that greater wealth generates more car use, but Table 4 shows that Swedish cities had a similar average GDP per capita (\$30,001) in 2015 to the Australian (\$32,194) and Canadian cities (\$31,263) in 2006, whose car and energy use per capita are much higher than in Swedish cities (around double or more in private transport energy use). Similarly, European cities had an average GDP of \$38,683/person in 2005, which was very much higher than the Australian and Canadian cities at that time, and yet all of their mobility factors are strongly oriented to public transport, walking and cycling, and they have much lower transport energy use per capita. These inconsistent relationships between wealth and transport energy use mean that wealth is generally a weak factor in predicting per capita transport energy use data at an aggregate level in cities across the globe. In the 2005–2006 data for the cities in Table 1, GDP per capita had the strongest positive relationship with private passenger transport energy use per capita, using a power function with an r<sup>2</sup> value of only 0.172. By contrast, urban density (persons per ha) showed a very strong negative relationship, with an r2 value of 0.827.

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**Table 4.** *Cont.*

#### *4.1. Di*ff*erences and Similarities in Car-Related Factors*

Firstly, Swedish cities had lower car ownership in 2015 (431/1000 people) than the European cities had in 2005 (463/1000), and the difference would have widened, since car ownership in European cities would have grown over the intervening ten years. This lower car ownership in Swedish cities will tend to reduce their energy use. However, they also have 2.5 times more linear length of freeway provision than European cities (0.242 cf. 0.094 m/person), which generally tends to increase per capita transport energy use in cities [29] because it encourages more driving over longer distances.

However, the average speed of individual vehicles is also known to be the most important single variable in explaining the fuel consumption of vehicles in traffic streams [30–32], with higher average speeds up to about 60 km/h being shown to reduce the consumption of fuel per kilometer in a vehicle. The ten Swedish cities have an average traffic speed of 42.6 km/h, compared to only 34.3 km/h in other denser European cities. Swedish average traffic speed is almost identical to the much more auto-oriented Australian cities (42.8 km/h).

While this result would tend to mitigate fuel use somewhat by reducing the fuel consumption per kilometer of vehicles in Swedish cities, it has also been shown that there is a trade-off between fuel-efficient traffic and fuel-efficient cities. Policies that try to minimize transport energy consumption by building more roads and speeding up traffic will, overall, tend to increase the amount of energy use per person through greater car-orientation of the city and more driving, and therefore should never be pursued [33].

Swedish cities also have quite similar parking spaces per 1000 Central Business District (CBD) jobs to their European cousins. European cities average 248 spaces/1000 jobs while Swedish cities average 289, though the larger Swedish cities have only 246 spaces/1000 jobs with the smaller ones being more generously supplied with parking (332/1000 jobs). Reduced parking in the CBD will greatly favor non-car modes, especially for the journey to work [34]. Overall, the similarity in Swedish cities with other European cities on this factor, and especially when compared to the very high CBD parking in US cities, will tend to reduce transport energy use. When this is combined with the relatively high centralization of jobs in their CBDs (17.3% in the Swedish cities overall and 18.3% in their smaller cities), the possibility of using public transport, walking and cycling to work is enhanced.

Table 4 shows that private transport modes constitute 55.7% of all daily trips in the ten Swedish cities, with a slightly better result in the five larger cities (53.5%). Other lower-density, auto-oriented cities in the USA, Australia and Canada have between 75% and 85% of daily trips by private modes. This is a very big factor in keeping Swedish car use and private passenger transport energy use per capita very much lower than it is in the USA, Australia and Canada.

When the fuel consumption rate in MJ/km and MJ/passenger km (PKT) is considered, as detailed earlier in the paper, it can also be seen that Sweden follows the European phenomenon of more fuel-efficient vehicles. For example, cars in the ten Swedish cities average 3.0 MJ/km, while the European cities average 3.1 MJ/km. In all other groups of cities, cars are consuming between 4.1 and 4.9 MJ/km. Likewise, considering passenger loadings, Swedish cities average 2.27 MJ/PKT, while European cities average 2.30 and the other cities average between 2.85 and 3.79 MJ/PKT. Thus smaller, more fuel-efficient cars in Swedish cities also help to suppress their transport energy use.

## *4.2. Public Transport and Non-Motorized Mode Factors*

There are a series of other important factors that make Swedish cities a somewhat unique cohort in the global system of cities. Firstly, relative to other lower-density cities, Sweden provides a lot of public transport infrastructure. The length of all public transport lines in the ten cities averages 8410 m/1000 persons, while in other European cities, it is 3183. In American cities, it is only 1382 meters, and in Australia, in the best of the auto cities, it is 2609 m/1000 persons. The reserved route length per 1000 persons is also high in Swedish cities with 716 m/1000 persons and only 298 in other European cities (reserved routes are those that are reserved only for public transport such as bus lanes and rail lines, including segregated LRT/tram routes), so that congestion from other vehicles does not interfere

with their operation. Other lower-density cities typically average only around 100 m/1000 persons. Additionally, the ratio of reserved public transport route to freeways (the two premium measures of private and public transport infrastructure) is 3.26 in the Swedish cities, only exceeded by other European cities with 5.51 times more premium public transport route than freeways.

This means that public transport systems in Swedish cities offer quite competitive average speeds. The ratio of overall public transport system speed (all modes) is 0.93 (so approaching parity with average road traffic speed), while in other European cities, it is 0.88. American and Canadian cities have public transport systems that operate at little more than half the average speed of general road traffic. The Swedish suburban rail services are especially competitive with road traffic, averaging 80.5 km/h cf. 42.6 km/h. Even Swedish urban bus systems have the best average speed of all buses in the world (30.3 km/h compared to a range in other cities from 19.4 to 23.4 km/h, with a global average of 21.5 km/h).

Furthermore, Swedish cities are blessed with relatively high levels of public transport service as measured by the annual seat kilometers of service per person. They provide on average 5720 seat km/person, with the five larger cities at 6895 km/person, which is more than other European cities (6126 seat km/person).

It could be concluded that Swedish cities do a great deal for public transport, to help compensate for what are atypically low densities for European cities and therefore quite dramatically reduced catchment densities around public transport stops. Stockholm is an exception here and has had a strong policy of transit-oriented development around stations on its tunnelbana (metro) system [35,36], thereby achieving the highest public transport use in Sweden (359 annual boardings/person), comparable to other European cities with 386/person. This suggests that even where densities are relatively modest overall (23.5 persons/ha in Stockholm), if significantly focused and denser, mixed-use urban fabrics can be developed and integrated with good public transport services, high levels of use can still be achieved.

Because of overall good infrastructure and service for public transport, the ten Swedish cities achieve what is a respectable performance in public transport use despite their lower densities. They average 128 annual boardings per capita and 195 in the larger five cities, compared to 67, 96 and 151 per capita in US, Australian and Canadian cities, respectively (and Canadian cities average 58% higher urban density than the average for the Swedish cities). Swedish cities are, however, 67% less in per capita boardings than in other European cities. Their public transport passenger kilometers are better, due most likely to longer travel distances, averaging 1390 PKT/person, compared to 571, 1075 and 1031 in US, Australian and Canadian cities, though they are still 38% below the European cities (2234/person). Swedish cities also have 16.3% of total motorized travel by public transport (20.4% in the larger cities), compared to only 3.2%, 8.0% and 11.3% in US, Australian and Canadian cities respectively. Not surprisingly, though, they lag the other European cities in this factor (24.5%).

The major public transport problem for Swedish cities is their low density. This can be seen in the vehicle and seat occupancy data. These data show how many people on average are in a public transport vehicle (for rail, a vehicle is one wagon of a train) and what percentage of the seats supplied are on average occupied. Table 4 shows that there are on average only 15 persons per public transport vehicle (23 in Stockholm), which is lower than all other groups of cities, apart from the American cities (13). In seat occupancy (24% for all Swedish cities), there are no groups of cities with lower occupancy, and the range is from 31% in Stockholm down to 10% in Örebro. Thus, there is a lot of unutilized public transport capacity in Swedish cities and therefore high energy conservation potential if occupancy of the generous services provided can be increased.

Finally, Table 4 also suggests that the strong orientation to non-motorized modes in Swedish cities, despite a cold climate for much of the year, is also contributing significantly to their moderate private passenger transport energy use per capita. Swedish cities average 30% of all daily trips by walking and cycling (and a further 14.3% by public transport), with 32.8% walking and cycling in the five smaller cities, not far behind the other European cities with 34.5%. This is in stark contrast to 9.5% in American, 14.2% in Australian and 11.6% non-motorized-mode use in Canadian cities. Despite low overall densities, Swedish cities do have significant areas of higher density, mixed use walking city fabric which facilitates greater use of both walking and cycling [21,37].

A simple way of summarizing the collective importance of all these factors in understanding transport energy use is to look at a pair of contrasting examples from Sweden with quite different per capita energy use in private passenger transport. Table 5 contrasts these key differences and shows that Jönköping has 80% higher private transport energy use per capita than Stockholm (21,678 MJ/person cf. 12,051 MJ/person). Furthermore, despite public transport use being dramatically less than in Stockholm (60 boardings/person cf. 359 in Stockholm), even public transport energy use per capita is a fraction higher (2050 in Jönköping cf. 1949 MJ/person in Stockholm). This highlights the energy conservation potential of public transport in a simple way—despite very similar public transport energy use per capita, Stockholm carries six times more boardings. The efficiency of energy use is also very different between the two cities. Jönköping's private and public transport energy use per passenger km are very similar (2.74 versus 2.53 MJ/PKT respectively) so that public transport has only a slight advantage in energy consumption. By contrast, private transport uses 2.4 times more energy per passenger km than public transport in Stockholm.

**Table 5.** Key differences between Stockholm and Jönköping with low compared to high per capita energy use in private passenger transport.


It can also be seen how different many of the other factors are between the two cities. Urban density is 87% higher in Stockholm, the proportion of jobs in the CBD is 1.4 times more, parking spaces per 1000 jobs are 2.3 times higher in Jönköping and GDP per capita in Stockholm is 1.6 times higher than Jönköping, despite Stockholm having significantly lower car use per capita than in Jönköping (6630 PKT/person cf. 7902 PKT/person). Freeway provision per person is 3.6 times greater in Jönköping, and car ownership is 21% higher, reflecting a higher commitment to the car than in Stockholm. Average road traffic speed is 45 km/h in Jönköping versus 37.1 km/h in Stockholm, thus encouraging more car use, although the ratio between public transport system speed and road traffic speed is

virtually identical in both cities due to Jönköping's average public transport speed also being higher (40.7 km/h cf. 33.6 km/h).

Although Jönköping has more public transport lines and greater reserved public transport route per person than Stockholm, this infrastructure is not as well serviced as in Stockholm (only 4330 seat km/person cf. 8294 in Stockholm). This is reflected in all the public transport usage variables in Table 5 being so much higher in Stockholm, including vehicle and seat occupancy levels. Such differences are, to a degree, expected, given the difference in density and therefore the reduced public transport catchment populations around stops/stations in Jönköping. Interestingly, in non-motorized mode use as a percentage of total daily trips, Stockholm only has a slight edge over Jönköping, and both cities are the two lowest of the ten Swedish cities in this factor.

When taken collectively, it is likely that there is a strong multiplicative effect at work in determining the differences in energy use between the two cities.
