I've been busy working on a number of major project tenders for the past few months but I thought it was time to create another post.
For this one I'm going to talk about congestion, what it is and how levels of it can be changed.
What is it Congestion
Congestion in its most basic sense is rather simple, its what happens when you get too many people doing the same thing. Congestion happens everywhere from on roads, inside a train carriage, along a railway line and even at the super market.
The initial effect of congestion is to discourage people from doing what they want to do. Each person has their own level of tolerance however the general rule is that the less congestion the better, unless your in a situation where congestion adds atmosphere such as a sports game.
From a transport perspective congestion makes your journey take longer and less pleasant. Even if the level of congestion doesn't make the trip take any longer levels of comfort are reduced, this is most evident systems such as trains and ferries where a user may choose to avoid traveling at a certain time to ensure they can have a seat on their own.
Another aspect of congestion is the interaction between other users and systems on your journey. For example, every intersection you go through on a journey results in a delay which adds to the level of congestion experienced and reduces the capacity of each approach at the intersection. This delay holds true for multiple form of transport such as road and rail systems and is the reason why we look at grade separation where they are high levels of interaction.
Impacts of Congestion
The two main impacts of congestion are longer travel times and the reduction of travel. Longer travel times reduces the distance an individual will travel which in turn reduces where they can choose to live, where the work, where they spend their money, what they do for recreation and how much free time they have.
The other impact is wasted time and lost productivity. The more time spent traveling the less time is spent doing what we are actually wanting to do, be it working in an office or relaxing on the beach. This loss of productivity does't just effect the individual but the community in general. When travel times are short and reliable we can build inefficiencies and greater levels of centralization.
For example, modern super markets are large warehouse sized developments that are able to provide lower prices by buying in bulk, minimizing transport and lower staffing costs. These developments are only possible by having a large throughput of customers. In order to have this they need to have either a densely populated catchment or a large catchment. If the transport network in the vicinity of the supermarket is too congested people will be put off from going to that particular supermarket and go elsewhere.
Reducing Congestion
Now that we know what congestion is, what happens when we try to reduce it.
To be in the position where you are trying to reduce congestion you would have to assume that congestion is a problem and therefore you are suffering from the impacts of congestion. In other words, people have already been taking steps to avoid the congestion themselves by choosing not to travel, traveling at different times, traveling on different modes or working/living in locations that aren't their first choice.
This means that when you do something to try and reduce congestion the improvement you make may result in these people coming back. This may give the impression there has been no change when in actual fact there has.
The most common place we see this is induced demand. This is often told as a phenomenon inherent with road construction and often used in a negative sense as an argument against road improvement. Induced demand however does not limit itself to roads but can go anywhere, it is simply humans taking advantage of the options they are given.
This then brings us to the question, is congestion the problem that we need to address or is it something else. We can certainly reduce congestion, we can put other disincentives on the transport system so that people don't want to use it, we could add so much capacity that everyone can use it all at once. But with finite resources and a desire to have a city that is not defined by its transport system means these aren't really an option.
This is what I will look into with my next posts.
From a transport perspective congestion makes your journey take longer and less pleasant. Even if the level of congestion doesn't make the trip take any longer levels of comfort are reduced, this is most evident systems such as trains and ferries where a user may choose to avoid traveling at a certain time to ensure they can have a seat on their own.
Another aspect of congestion is the interaction between other users and systems on your journey. For example, every intersection you go through on a journey results in a delay which adds to the level of congestion experienced and reduces the capacity of each approach at the intersection. This delay holds true for multiple form of transport such as road and rail systems and is the reason why we look at grade separation where they are high levels of interaction.
Impacts of Congestion
The two main impacts of congestion are longer travel times and the reduction of travel. Longer travel times reduces the distance an individual will travel which in turn reduces where they can choose to live, where the work, where they spend their money, what they do for recreation and how much free time they have.
The other impact is wasted time and lost productivity. The more time spent traveling the less time is spent doing what we are actually wanting to do, be it working in an office or relaxing on the beach. This loss of productivity does't just effect the individual but the community in general. When travel times are short and reliable we can build inefficiencies and greater levels of centralization.
For example, modern super markets are large warehouse sized developments that are able to provide lower prices by buying in bulk, minimizing transport and lower staffing costs. These developments are only possible by having a large throughput of customers. In order to have this they need to have either a densely populated catchment or a large catchment. If the transport network in the vicinity of the supermarket is too congested people will be put off from going to that particular supermarket and go elsewhere.
Reducing Congestion
Now that we know what congestion is, what happens when we try to reduce it.
To be in the position where you are trying to reduce congestion you would have to assume that congestion is a problem and therefore you are suffering from the impacts of congestion. In other words, people have already been taking steps to avoid the congestion themselves by choosing not to travel, traveling at different times, traveling on different modes or working/living in locations that aren't their first choice.
This means that when you do something to try and reduce congestion the improvement you make may result in these people coming back. This may give the impression there has been no change when in actual fact there has.
The most common place we see this is induced demand. This is often told as a phenomenon inherent with road construction and often used in a negative sense as an argument against road improvement. Induced demand however does not limit itself to roads but can go anywhere, it is simply humans taking advantage of the options they are given.
This then brings us to the question, is congestion the problem that we need to address or is it something else. We can certainly reduce congestion, we can put other disincentives on the transport system so that people don't want to use it, we could add so much capacity that everyone can use it all at once. But with finite resources and a desire to have a city that is not defined by its transport system means these aren't really an option.
This is what I will look into with my next posts.
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