Wednesday, 28 January 2009

From Politics to Maintenance



On my way to the office I listened to an interview on the radio. The reporter was interviewing the project manager of the largest infrastructural building site in the Netherlands, the construction of the orbital motorway around Eindhoven. The project manager indicated that the project would take 4 years. During that time the current traffic, around 150.000 vehicles per day, needs to by-pass Eindhoven using temporary roads. During the project these temporary roads will change constantly. Today nearly every driver in the Netherlands has a TomTom kind of navigation system in the car, which is trusted without question on directing the user to its end destination. These systems are a very good example of how practical Operations Research can be. The situation around Eindhoven however changes every few weeks, which causes some of the drivers that blindly follow the directions from their navigation system to end up between the builders. A good example that even though you have a wonderful system available to solve an optimization problem, you still need to be aware of the conditions under which you apply it. At least some of the drivers around Eindhoven know that now.

The interview on the radio also brings back some projects that I did in the past with respect to road construction, that are nice examples of how broad the application of Operations Research can be. To start with, in the Netherlands the Ministry of Transport, Public Works and Water Management is responsible for the maintenance and construction of roads. They develop a long term plan in which specific projects are scheduled to either construct, changes of maintain roads. Based on that long term plan, a yearly budget is determined that is announced on the annual speech of the Throne on the third Tuesday of September. The challenge in developing the long term plan is that projects usually take longer than 1 year, and in each year a certain budget is required. The budget approval from the House of Commons however is for one year only. Also the scheduled projects cannot be stopped as soon as they have started, and as you can imagine, some of the projects take more time and therefore more money. Also the projects are related and have precedence relations. Every year the long term plans needs to be reviewed and revised to come up with a new annual budget. The number of projects is quite large, so manual adjustment is out of the question. This is where Operations Research comes in. Actually, the problem the Ministry of Transport, Public Works and Water Management faces is a capital budgeting question which we solved using a linear programming model. With this model the Ministry was able to decide which projects to start or postpone and so meet the budget requirements, but also have the projects with the highest priority scheduled as soon as possible. The model supported the Ministry to objectify the project scheduling, making it a less political decision. Maybe they should use Operations Research more for example better estimate the risks involved in large infrastructural projects.

On the other side of the spectrum, I was also involved in a project in which the objective was to find the cost optimal strategy to maintain road section. The cost identified was used for the above budgeting process but also to compare it with the offers submitted by the road construction companies that would like to get the maintenance contract. So Operations Research enabled a sanity check on the offers done by the road construction companies. With the optimal maintenance strategy available, the government was able to challenge the construction companies, leading to more efficient road maintenance at a lower cost. Finding the optimal maintenance strategy was a challenge in itself. Based on actual the road conditions (holes, bumps, wear and tear) the model we developed was able to define the best maintenance strategy for each part of the road. We accomplished that by dividing the road into (virtual) tiles en for each tile decide to either lower it (scraping of the tarmac) or raise it (put on tarmac). Using a dynamic programming formulation the optimal maintenance strategy was identified, taking restrictions on bumpiness of the road, angle, etc, into account.

So Operations Research can be very hands-on giving you an exact plan on how to maintain a road segment and helps to identify the best maintenance offer. On the other hand it also supports decisions on governmental level, making the difference between what’s logical and politics.
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