Letter: Gambir drunk driver was speeding

This is a comment from The Jakarta Post on the article titled “Experts say Gambir drunk driver was speeding” published on June 14 on page 9.

Two passengers have given estimates of the car’s speed “at the time of the crash”, but we are not told how they made their estimates. Were they watching the speedometer, for example? Did they notice the driver making the swift gear changes necessary to accelerate a Toyota Avanza up to 90 kilometers per hour out of second gear? Or do they have special gifts that enable them to calculate speeds to the nearest tenth of a kilometer per hour just by looking out of the window?

Nor is the testimony of the prosecutors’ physics expert clearly explained. Was 99 kilometers an hour the maximum speed he measured? If so, how long was this speed sustained for? What was the average speed for the period during which the car was captured on CCTV? What was the purpose of separating the film into individual frames? To estimate the car’s speed, it would be best to measure the displacement over a period of a second or more, since trying to measure displacement over a period of only one thirtieth of a second would be too imprecise to give a reliable speed estimate.

Nor are we told where the CCTV camera was located.

It is also noticeable that the opening sentence refers to “experts on physics and traffic safety”. But the traffic safety expert is not identified and no details of his testimony are given.

Of course it is hard for journalists to report clearly from Indonesian court rooms, where nobody much cares about establishing the facts, but it would be nice to get a better picture than this.

John Hargreaves
Jakarta