by Soovin Yoon
After taking the Introduction lecture of this ISyE 823 class, I couldn’t help thinking about my first public sector OR problem. I was remembering that just as an ambiguous failure, but its details and reasons suddenly came to my mind due to class material.
When I was a sophomore, I took Scientific Management course that involves a term project to improve a bus service, named route K-02. As the university was located high up in the mountain, students had to take K-02 to reach the university from the subway station. There was two serious problems with the bus; it was always terribly packed, and it took a long and dangerous detour.
The cause of the detour was very clear. The route included a tiny apartment complex, named I-Apartments. I-Apartments was located on the hill, and the only path that connects it to the main street was very steep, narrow and winding. So students, faculties and staffs were complaining about their dangerous commuting route.
First it looked logical to simply remove the detour from the route to maximize the total satisfaction of the customer. Then people from I-Apartment will have to walk down a few minutes to use the bus, but since their number is quite smaller compared to university members, it won’t affect the average satisfaction that much. But it was unfair. K-02 was the only available public transportation for the resident of I Apartments to reach the subway station. The bus had a responsibility to provide the only service they can get.
The most popular solution from the class was installing a signaling system (a flag or traffic light), so that if there is anyone from I-Apartments waiting for K-02, then one can signal so that the bus can take the detour under the necessity. Otherwise the bus can skip the detour. This looked like a lovely flexible, reasonable solution. But thinking about how much additional attention the driver need to be in charge, how much unpredictable the bus schedule will be, and how upset a passenger will be if the passenger is late for the class and the bus suddenly takes unexpected detour – this was still unacceptable. It was too flexible.
One of the other solution was to remove the detour from K-02, and substitute its function of connecting the apartment to the subway by other route, K-04, which is less busy as it does not go to the university, and of which the original route is not very far from I-Apartments. This was also rejected as this involves too many changes in the system. Officials did not want to disturb the other bus route. It turned out not to be our decision variable at all.
In the end, we were unable to generate a solution good enough to be implemented. It was difficult for me at that time to understand why we had to fail. Now I am totally overwhelmed to see how even a simple and small problem like this can possess multiple issues of equity, determinacy and authority, as we are dealing with the public society.
Let me finish the post with short introduction about myself. I’m a PhD student in Industrial and Systems Engineering at UW. Now I am studying a dynamic priority reassignment problem in emergency medical services. And of course there are lots of issues other than objective maximization due to publicity of the problem. (For example, we don’t want to abandon a specific patient, just because abandonment actually helps us saving the resource and improving the objective function. We need to be there.) So here lies my expectation of the course. After taking the course, I want myself be a better decision maker in my next public sector operations research problem.