why did "Traffic" just use my location?

Because Apple collects traffic data unless you turn it off in system services.

It's how traffic data is gathered for maps. Crowd sourcing. If you use the data, give back by disclosing your rate of speed while driving so maps can determine it you're green, yellow, or red.

I would certainly assume that Traffic data was only collected whilst using the Maps app in a car to navigate a route, otherwise the data is useless.
Looking at the apps you had opened there is no reason it should have been collecting data

Crowd sourcing. That is why traffic data is so good.

Aah. So you want to check the traffic status but you are not willing to contribute to its data is that it?

Can everyone please read the original post and the information contained within it.
The OP states that the only apps running were "Phone, Messages and Tweetbot"
Maps was not running, no navigation was taking place, therefore no traffic data should have been sent or received.

To the OP, please confirm what software level you were running and if you don't get any help, try the forums at Apple.com instead

davehutch said:

Can everyone please read the original post and the information contained within it.
The OP states that the only apps running were "Phone, Messages and Tweetbot"
Maps was not running, no navigation was taking place, therefore no traffic data should have been sent or received.

To the OP, please confirm what software level you were running and if you don't get any help, try the forums at Apple.com instead

Click to expand...

Map info is collected at all times... he need to turn it of....

Privacy>Location Services>System Services.. I turn off everything but Cell Network Search

it doesn't matter which apps you're using. If iOS 6 believes your traveling it'll periodically collect your location anonymously.

...if you are traveling (for example, in a car) and Location Services is on, a GPS-enabled iOS device will also periodically send GPS locations and travel speed information in an anonymous and encrypted form to Apple, to be used for building up Apple's crowd-sourced road traffic database. The crowd-sourced location data gathered by Apple does not personally identify you.

Click to expand...

Source: http://support.apple.com/kb/HT5467?viewlocale=en_US&locale=en_US

Traffic is only one aspect of Location Services and you would need to be travelling in a car. If you're walking or sitting on your sofa, traffic data is of no use whatsoever.
The system needs to know you're navigating...in a car, otherwise it would show the entire World as a traffic jam.
Speed is one way the system would know you're in a car as people can't walk faster than about 5mph, however, a traffic jam often moves at walking speed.
Trains, travelling parallel to a road would also give erroneous data if you we're on one and traffic data was collected.
What if one hundred people were travelling on a train at 80mph, and the train ran alongside a road with a traffic jam on?
Which data would be ignored and why?
It would therefore make sense to only send/receive traffic data whilst navigating with the Maps app...wouldn't it?

davehutch said:

Don't be ridiculous. If you're walking or sitting on your sofa, map data is of no use whatsoever.
The system needs to know you're navigating...in a car, otherwise it would show the entire World as a traffic jam

Click to expand...

It can easily tell if someone is driving if it periodically checks.

LoloBond said:

Map info is collected at all times... he need to turn it of....

Privacy>Location Services>System Services.. I turn off everything but Cell Network Search

Image

Click to expand...

I've turned everything off under that system services including cell network search. I never have an issue getting a cell signal, using maps etc.

Paranoid much?