Cost of Jakarta Traffic Jam

I use Jagorawi toll highway connecting Jakarta and Ciawi at least once a month to give a teaching workshop in Cianjur. Every time I go back to Jakarta, there is always a huge traffic jam - a few kilometers - where cars line up to wait to pay at the toll booths. This traffic jam is caused by a misplacement of toll booths that actually block the traffic. It is a real example of mismanagement gone horribly wrong.

There are of course daily traffic grinds everywhere in Jakarta during morning and evening rush hours. These gridlocks are quite maddening even to watch and cost big time to Jakartans. How do I estimate the cost of the traffic jam?

It is not difficult to estimate the traffic jam cost. (No need for a Ph.D., LOL!) All I need are a few facts:

(a) End-to-end length of a traffic jam per hour = 3 km. This number comes from an estimated average speed of a car crawling through a traffic jam.

(b) The amount of fuel wasted per hour = 6 liters. This number comes the Consumer Energy Center, California Energy Commission website, which states that "For every two minutes a car is idling, it uses about the same amount of fuel it takes to go about one mile." When the car idles for an hour, then it is equivalent to travel 30 miles (= 48 km). With an average fuel mileage of 8 km/liter, an hour idling will thus consume 6 liters.

Note: Does 6 liters make sense? If a car moves with a speed of 90 km/hour, it will consume about 11.3 liters. The idling thus costs about 50% of the fuel consumption. When a car idles, the only car parts that do not move are the axles that turn the wheels and the drive shaft. The engine is still running though, idling or not. The 50% fuel consumption fraction during idle corresponds to the fuel consumed by the running engine.

(c) The loss of productivity per person per hour = Rp 62,500 (about $7/hour). I get this number by assuming an average salary of Rp 10,000,000/person. A month has on average 20 working days and each lasts 8 hours. Hence, the salaryman costs Rp 62,500 per hour.

Okay, now the traffic jam cost calculation goes like this. Calculate only the cost per hour of moving a 3-km traffic jam filled with cars. Since car-to-car distance is about 10 m, then there are 300 cars in the 3-km traffic jam per lane.

Each car can be assumed to have 2 workers with the mentioned salary. Thus, there are 600 salarymen got stuck and the labour cost is therefore Rp 37,500,000/hour per lane for every 3-km traffic jam.

In addition, the fuel cost is equal to 300 cars x 6 liters/hour = 1800 liters. The cost of premium is Rp 4500/liter, so that the fuel cost for such traffic jam is Rp 8,100,000.

The total cost = labour cost + fuel cost = Rp 45,600,000 per lane for every 3-km traffic jam. For a 1-km traffic jam that lasts for one hour, it therefore costs Rp 15,200,000 per lane. This is the unit traffic jam cost worth remembering!

I estimate Jakarta has about 500 km of main thoroughfares that experience daily traffic jams. Each morning and evening, these traffic jams last 1 hour (in which the speed crawls to 3 km/hour), so each day the traffic jams last for 2 hours. In addition, there are on average 2 lanes for each thoroughfare. Hence each day, the traffic jam cost is

500 km x 2 hours x 2 lanes x Rp 15,200,000/km/hour/lane = Rp 30,400,000,000!

It is a lot of money! It costs abour Rp 30 billion rupiah (with nine zeroes!) per day. In a year, it will cost Rp 11,096,000,000,000 = Rp 11 trillion rupiah (with twelve zeroes!).

Jakartans need to wake up and spend this money somewhere else, such as making more efficient rapid transit system.