Advances in personal mobility—the capacity to move when and where we want at a reasonable cost in time and money—are vital to a person’s life satisfaction. Since the early 1900s, access to personal vehicles transformed many people’s daily lives. Global car registrations increased from about 98 million in 1962 to 1.1 billion in 2019.¹ The expansion of personal travel by all modes caused widespread economic, social, and environmental change. The energy historian Roger Fouquet explored these issues in his investigation of personal transportation services in the United Kingdom over seven centuries (1300-2000).^2,3

Passenger transportation service is measured by moving one person over a given distance, so the units are passenger-kilometers or passenger-miles. The price of passenger transportation service is a function of the cost of the energy source (fodder, coal, gasoline) and the efficiency of the device (horse, railroad, auto) that converts the energy into actual transport.

Taken as a whole, the price of energy for transport (fodder until the mid-nineteenth century, coal until the mid-twentieth century, and then oil) more than doubled in real terms from about 1500 to the early 19th century. The price of horse fodder (a combination of hay, oats, and peas) rose rapidly in the 16th century due to the increased crops required to feed the growing populations of humans and animals. The price of coal increased between 1600 and 1800 due to rising coal consumption and the imposition of taxes on coal beginning in the late 17th century. The price of gasoline and diesel fuel for automobiles exhibited no distinct term trend from 1925 onwards, although there were short-term changes caused by events such as the oil market upheavals in the 1970s.

Data for price passenger transport services are only available starting at the beginning of the eighteenth century. In addition to fuel costs, the price of passenger transport services is determined by (i) the types of vehicles and vessels used to carry people, (ii) the efficiency of those vehicles and vessels, and (iii) the nature and quality of the transport networks. The last factor encompasses the direction and speed of travel on roads, canals, and railways, and the physical quality of the infrastructure itself.

Improvements in the efficiency of the steam engine dramatically lowered the cost of rail transport in the 1850s and 1860s. The internal combustion engine appeared in the late 19th century, and it too underwent dramatic and ongoing efficiency improvements. The combination of generally following fuel prices and higher quality and more efficient vehicles produced a fifteen-fold decline in the cost of passenger services between 1850 and 2000.

Note the decoupling of the price of transportation services and the price of fuel used for transport in the 20th century. The long-run decline in fuel prices ended in the 1920s, but efficiency gains were sufficiently strong to extend the long-run decline in the price of the service itself.

The substantial decline in the cost of personal transportation had a very predictable outcome: a commensurate surge in the consumption of personal travel. In 1850 Britons consumed about 4.6 billion passenger-kilometers. By 2000 consumption of travel had surged to 738 billion passenger-kilometers.

Ubiquitous access to relatively cheap mobility undoubtedly improved the quality of life and for many Britons. But the social costs of personal transportation–congestion, accidents, noise, health, pollution–are staggering.⁴ Most of these costs are what economists call negative externalities, meaning that they are born by society at large, not the owners of the personal vehicles.

The period of rapidly declining cost of personal transport was (and continues to be) dominated by fossil fuel use, first coal in steam engines and then oil in internal combustion engines. The fossil fuel energy system accounts for a significant fraction of pollutants released into our air and water, and they dominate greenhouse gas emissions. Like most other countries, the United Kingdom faces the challenge of expanding, clean, affordable, and equitable, personal transportation services that are decoupled from heavy reliance on fossil fuels.

1 Davis, Stacy C, and Robert G Boundy. “Transportation Energy Data Book: Edition 40.” Oak Ridge, TN: Oak Ridge National Laboratory 2022. Link

2 Fouquet, Roger. “Divergences in Long-Run Trends in the Prices of Energy and Energy Services.” Review of Environmental Economics and Policy 5, no. 2 (July 2011): 196–218. https://doi.org/10.1093/reep/rer008;

3 Fouquet, Roger, and Peter J. G. Pearson. “Seven Centuries of Energy Services: The Price and Use of Light in the United Kingdom (1300-2000).” Energy Journal 27, no. 1 (January 2006): 139–77. https://doi.org/10.5547/ISSN0195-6574-EJ-Vol27-No1-8.

4 Gössling, Stefan, Jessica Kees, and Todd Litman. “The Lifetime Cost of Driving a Car.” Ecological Economics 194 (April 1, 2022): 107335. https://doi.org/10.1016/j.ecolecon.2021.107335.