In terms of change over time, the most fundamental shift of travel behaviour in cities over the last five decades is linked to the rapid increase in global levels of motorisation, and a substantial shift away from non-motorised and public transport.
Additional sensitivity analyses were based on age and shift of travel mode scenarios, considering only physical activity, the main driver of the results.
We quantitatively compared the health benefits from physical activity with the risks related to air pollution and traffic accidents between cycling and car driving for short trips, distinguishing the individuals who shift modes of travel from society as a whole.
The shift of business travel to regional airports is illustrated by Federal Aviation Administration statistics.
As the general perception of public transport improves, data collection might thus facilitate a long-term shift of urban travel towards public transport.
Included in the sensitivity analysis were, for example, relative risk functions from the literature, choice and toxicity of pollutants, age distribution, shift in mode of travel, and environmental and travel conditions in Barcelona.
Importantly, no study has examined the correlates of the most common mode shift - shifting from passive modes of travel in the morning to active modes of travel in the afternoon [ 3, 20].
This has also shifted a class of travel from personal shopping into freight, where vans or lorries do multiple drops as the final stage of a logistic process, says Phil Goodwin of UCL and the University of the West of England.The decline in visiting friends and family at home is harder to explain.
If shifts in mode of travel were generated predominately from walking and public transit, the savings in carbon dioxide emissions would also be lower than our estimations.
However, we did not consider the possible positive effects of the Bicing initiative in encouraging cycling not using Bicing thus triggering a larger number of shifts in mode of travel, nor the potential for cycling trips to replace longer trips in vehicles (there may be a leveraging effect of the cycling policy), which would all lead to estimating greater benefits on emissions.
Data on shifts in mode of travel as a result of the Bicing initiative could not be found, but using an alternative scenario with 60% of Bicing users having shifted from public transport, 30% from walking, and 10% from car, had little effect on the number of deaths avoided (10.46 v 12.46) (see web extra table 9).
