If your vehicle stalls in traffic, what should be your first course of action?

The first course of action when your vehicle stalls in traffic should be to attempt to restart the vehicle. This is because resolving the issue yourself can help to quickly clear the obstruction from the road, ensuring the safety of both yourself and other road users. Restarting your vehicle helps to minimize disruption in traffic flow, which can reduce the chance of accidents or additional incidents.

While waiting for assistance, calling emergency services, or turning on hazard lights are useful actions in certain situations, they are secondary to resolving the issue directly if you're capable. Turning on hazard lights is important for alerting other drivers to your stalled vehicle, but it does not address the immediate problem of getting your vehicle moving again. Waiting for assistance or calling emergency services can further delay the resolution of the situation, which is less favorable when compared to attempting to restart your vehicle. Thus, the most responsible first action is to try to get your vehicle running again.