My view on public transport efficiency

My view on public transport efficiency

I have records of some journeys made by public transport for my analysis. The model I use is the generalised cost of the journey taken in isolation. In the value of time conversion, I currently use HKD 12.0 per hour as a passenger and HKD 18.0 per hour for walking, waiting or driving, using the price index of January 2015. These figures may be adjusted if I find them contrary to my personal preferences.

I consider, if the generalised cost is below 10, the journey is “cheap” that I am willing to travel on a frequent basis; if it is about 15, I am still willing to travel occasionally; however, if it is above 20, the journey is “expensive” and I tend to make arrangements to minimise the cost; if it is above 30, I start taking transport into consideration to decide if I am willing to go to that place to join the activity.

From my home in Mong Kok, a generalised cost of 10 can bring me to areas like Tsim Sha Tsui, Admiralty, Wong Tai Sin, while 15 can bring me to places like Kwun Tong, Causeway Bay, Lung Fu Shan (HKU). Travelling to suburbs like Tseung Kwan O, Fung Shue Wo, Fu Shin and Chai Wan Kok costs me about 15 to 20, while travelling to rural areas in Hong Kong SAR like Sai Kung, Sheung Shui, Stanley, Tin Shui Wai, Yuen Long, Clear Water Bay, etc., normally costs me 20 to 30, in some extreme cases, the cost may even reach 40 like going to Wong Shek Pier.

There were a few recorded journeys where the cost is more than 40, these were normally long journeys involving rural areas and/or crossing the border. In particular, the journeys between Tai Hing and Tangjiawan, which are about 41 km apart, were the most expensive, costing between 190 and 200, mainly because they involved super expensive coach / ferry, long time in taking the coach and long time in multiple transfers to / from the ferry. (In my experience, the costs tend to be much higher if the points of the journey is separated by the sea. In these cases, Tai Hing and Tangjiawan are separated by “the great sea” (大海), because in Hong Kong everyday usage, “across the great sea” (過大海) means travelling to Macau, therefore, “the great sea” refers to Pearl River Estuary.)

Although the generalised cost is a good indicator of my willingness to take the journey, the longer the distance, normally the higher the cost. My analysis on the data has shown me that, by dividing the generalised cost by the square root of the distance, the resulting figure is statically irrelevant to the distance, and can be used as an efficiency index from travelling from a place to another. This number currently ranges from 2.79 (the most efficient) to 31.18 (the most inefficient), where the inter-quartile range is 5.18 to 7.83. The small inter-quartile range means that in most cases the generalised cost of the journey can be predicted from its distance. For example, taking the MTR East Rail Line from Mong Kok to Wan Tau Tong is very efficient (using very low cost to travel a long distance), where the index is about 3.82, while taking bus no. 1 from Kowloon Tsai to Mong Kok is very inefficient, where the index is about 10.73. A journey of about the normal efficiency is taking the Tsuen Wan Line and Island Line from Mong Kok to HKU, where the index is about 6.20.

The notion of transport convenience can be derived from the above index. If the index is high (inefficient), there is the possibility of using an inferior method (for example, from Kowloon Tsai to Mong Kok, a much better option is taking the MTR from Lok Fu to Mong Kok). However, if there is no method where the index is low, I can say that the transport there is inconvenient (hard to get there efficiently), especially if there is no efficient method from a place to multiple places. For example, Sandy Bay is a place where the transport is inconvenient. In contrast, the transport is convenient (easy to get there efficiently) if there exists a method, or even multiple methods, where the index is low. For example, the transport to Tsim Sha Tsui is convenient because I can easily get there efficiently from multiple places.

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