Traffic Theory

The traffic in Chennai is horrible. Totally crazy. You wud reach ur office in an hr one day and in 15 mins the other. I have been critical abt the traffic sense of ppl and never gave it more thought.Looks like my dad also frets abt it.....and a friend of his, from Mumbai, came up with this theory.
' In Mumbai say the time taken for a journey is 1 hr; even if one day we reach the place in 20 mins, we dont reduce the average time fixed, proportionately. So we prepare to leave an hr early on all days. Wheras you in Chennai would re-calculate the averages and start the next day with just abt 40 mins to spare. If something goes wrong, say just for abt 5 mins, you feel the entire system is crashing and panic leads to more delay'
This is not THE reason...but definitely makes sense.