My tempertature gauge goes up in heavy traffic. When I start moving it gets back to normal.

This is a normal condition for this model and many more. There maybe an issue with your engine oil or coolant systems. If you can flush the radiator & coolant system clean on next service & replace with a fresh quality brand of new coolant then you may have solved some of the problem. The other is if your rad fans are kicking in enough or at all. So do a stationary check in your garage. let the engine warm up on idle. Then when it reaches a heat that will kick in the fans check what the Temp-gauge is reading & make a note.
You may have a weak oil pump or water pump. Check the pumps records & see if they are newish or first day. Water circulation is very important in a cars system. So in slow traffic the engine is running at low rev's & gets hot due to slow air speed through the rad. So the water pump is there to keep the pressure up at all times. It could be the No:- problem with your car.
After that get an engine oil pressure test done & compare with the results data spec-sheets from its manual.

If you are asking the normal position of the temperature gauge needle in normal operating mode it will be about half way in the gauge reading( between cold and hot). IT may vary about a needle width regardless of the load on the engine and if it climbs up in traffic then you have a problem with the fan operation

If you have a viscous fan hub then have it replaced as it is not drawing air through the radiator at idle or slow speed (crawling traffic). Check that are no air locks in the system as they will cause heating problems.

sounds to be a stuck thermostat

IT IS NORMAL FOR A VEHICLE TO HEAT UP WHEN THE A/C IS ON ESPECIALLY IN HOT CONDITIONS IF THE VEHICLE IS NOT OVERHEATING THEN THIS IS NORMAL IF YOU WANT YOU CAN ADD A HEAVY DUTY OR HIGHER GRADIENT THERMOSTAT TO BETTER REGULATE THE GUAGE

it is normal for the temp gauge to show a little over the normal mark in heavy traffic as long as it is not going into red its okay

Check
1)thermostat and also that the electric fan is kicking in when it gets above normal temp
2)blocked radiator
3)worn water pump (more so from electrolysis, ie not using the right antifreeze)

1.Low coolant level,2. restricted rad. ( full of dirt, bugs etc.)3. Idle too low.4. Fan not cutting in.5. Water pump.

I had this exact same problem -- for about a year and a half! Replaced thermostat, replaced sensor twice, replaced overflow tank, replaced radiator cap, placed a grounding kit on the car in case the problem was electrical ... and was ABOUT to replace thermostat again and then the water pump when a new mechanic suggested we bleed air out of the cooling system. The heater core was PACKED with air, as was the upper hose valve area. Previous mechanic had been using a pressurized fill device to bleed the system and this had just been backing air into the heater core. There are two valves under the hood for bleeding air -- one on the heater core and one on the upper hose. It only takes a few minutes to fix this!

Well let's see....You did not say the temp of the heat changed inside your car... if it does NOT ...I say the gauge is messed up....

A thermostat usually sticks open or closed.. if it is broke.

If it is defective the car will start getting hotter under a load going uphill or....when the a/c is running it will not put out cool air while sitting still at a stoplight or heavy traffic..