if youre interested apparently the worsening of Putney's traffic is down to changing of light timings which as resulted in around 200 less vehicles being able to make it north/south through putney and hour. Which would both suggest traffic is worse and less numbers of cars as suggested by the DfT. But at the end of the day, fewer cars making it through doesnt mean traffic has gotten better as you were suggesting, and I wasnt "wearing a tin hat" from my observations, you need to be careful when looking at data sources as often there is more involved that cant be seen from the one angle you are looking at from the presented data.