I doubt if it's anything to do with your temp sensor. It only takes readings. Your radiator is inefficient and temps overheat while in standstill traffic.Since you're driving to long distance better to ensure the pipe and temperature is in good condition. Car at this age is prone to temperature sensor issue. It took me a while to fix that. I was not able to drive at all. Temperature started to rise once I'm caught in traffic jams. Air-cond cut off and blowing hot air. Ended as what gunnerzz said, I changed all the pipes, service the radiator (full of mud) and change a temperature sensor too.