Overheating

An overheating condition can be caused by several things. The thermostat in the engine may not be opening enough or quickly enough. The engine cooling fan could be not functioning at all, causing no air flow in start / stop traffic. You could have poor coolant flow from a water pump issue. You could have an air flow restriction at your radiator. Your coolant reservoir cap may be not pressurizing your system properly. Your engine may have a coolant leak within your engine - such as with a leaking cylinder head gasket. I know I didn't clear anything up for you - but I think it's important to not oversimplify the situation, and encourage you to have a test performed prior to do any further driving. More driving and more overheating may cause extra damage to the engine and cooling system.