Question: What are the social effects of being able to go to places?
Accessibility is the possibility of going to places to do something. Accessibility is key for our lives, because much of what we want to do it’s outside home (although these days many things can be done online). So accessibility (and lack of) can affect our employment and education, income, health, and wellbeing.
Accessibility depends on how far are the places we need to go. It also depends on whether we have the means to go there, i.e. transport. And on how fast and convenient that transport is.
There are several questions we can ask about accessibility. Here are two examples, from my research.
Example 1. How to measure accessibility?
Accessibilty can be measured in a simple way as the travel time to go to the nearest place, out of all the places where we can do something. It can be measured in a more complex way, combining the attractivness of all those places with the travel time to go there.
In my PhD I used indicators that measure how accessibility is unequally distributed among residents in different areas of a city (Lisbon). This was by measuring the relationship between the estimated average commuting time of people living in a given area and
- the potential accessibility to jobs in that area
- the commuting time if those people commuted using the fastest mode available in that area (which is usually the private car)
- the commuting time if there was no road congestion
Using these indicators, it is more visible which groups are at a disadvantage. For example, groups with lower socio-economic status were at a disadvantage when considering the first and the second indicators above. But those with higher status were at a disadvantage when considering the third indicator.
Example 2. What happens when people gain or lose accessibility?
Accessibility can increase when a new road or railway is open. Likewise, accessibility can decrease if they close. Roads seldom close. But railways can close. That happens quite frequently, especially in the more isolated regions of European countries.
I am interested how the closure of railways contributes to the population decline of villages. I am especially interested in the case of Portugal. The less urbanized regions away from the coast have been losing population for several decades. In the same period, many railway lines were closed in those regions. Maybe the two things are related?
In this paper, I showed that when the lines closed, they still had the potential for serving many people living in the areas around. This suggests that the closure of the lines was not because of loss of population. So it could be the loss of population that was the effect of closure of the lines.
In this paper I used statistical models to try to explain population changes in those areas. I found that places that had a station nearby which was then closed lost more population than other places, when controlling for all other factors affecting population. But that did not happen in all periods.
In another paper, with Portuguese colleagues, we found that rail accessibility did not have a significant relationship with population. But road accessibility had. The increase in road accessibility (because of the many new motorways that were opened at the same time that the railways closed) was related to smaller losses in population in the area served. We think that the insignificance of the rail accessibility variable could be because the indicator we used was simple.