In case you hadn’t heard, fuel prices are going through the roof at the moment. But I guess that you have heard of this already. And it is causing much in the way of commentary. One thing that has been missing from this commentary – which mainly boils down to whether or not fuel duty should be cut – is what impact this will have on demand for sustainable transport.

This is something that has…not been studied that much relative to its importance, actually. But where there is good evidence is in relation to the use of public transport, where cross elasticities of demand (how demand for one mode changes in relation to the changes in price of another mode) have been studied for a number of years. This excellent report by the Victoria Transport Policy Institute goes into great detail on this.

With public transport, the research shows that when fuel prices for cars increases, the demand for public transport increases a little, and even then it depends on whether it is a realistic alternative. Research from APTA in 2011 showed that…

Regular gasoline prices increased 35% from $3.053 per gallon on 31 December 2007 to a peak of $4.114 on 7 July 2008, then declined 61% to $1.613 on 27 December 2008. Transit ridership increased during this period, with a 3.42% increase during the first quarter, 5.19%, and 6.52% during the third quarter, indicating a lag between fuel price and transit ridership changes.

Meanwhile, the TRACE project found that demand for public transport increases by 0.13% for every 1% increase in fuel prices. While evidence from Chicago shows that the level of demand for publice transport generated by fuel price increases is related to what the fuel prices originally were. For every 1% increase in fuel prices, demand for public transport in the city grew by less than 0.05% when fuel was less than $3 a gallon, between 0.12% and 0.14% when fuel were more than $3 a gallon, and between 0.28% and 0.37% when fuel prices were more than $4 a gallon. To give an indication, the current price of fuel in the UK is more than $8 a gallon.

For cycling, there is a lot less evidence, but what there is shows encouraging signs. Short run demand estimates of the impact of rising gas prices on bikeshare use in the US shows that the demand for trips increases by 0.726% for every 1% increase in fuel prices. But the average trip duration decreases by 0.098%. The latter largely being as a result of there being more short trips. While data from a panel study in the UK shows that people tend to shift to walking and cycling when fuel prices increase. For walking there is even less data available.

The obvious conclusion to make here is that as fuel prices increase, demand for public transport will also increase, and it is likely that demand for cycling will increase, and in all probability the amount of walking will increase. And it is a logical one. For me, though, a far more likely outcome is this: people will simply take less trips altogether. Whether or not that is a good or bad outcome I will leave for yout to decide.