[johnwalkr]

As the article said, several microphones are required to pinpoint the location of sound. Location and distance are very important to measuring sound.

I forget what city recently tried to enforce vehicle noise, but I recall reading that virtually all tickets were thrown out under argument that the distance, angle of meter, nearby materials weren't perfect enough to measure adequately.

Furthermore as far as I've seen, measurements are with a handheld meter after the vehicle is pulled over, not when the driver is wide-open-throttle and over the speed limit.

It makes much more sense to measure from a fixed location while the vehicle is in motion.