if you are sitting in traffic for long periods of time or stationary for more than a few minutes, it's always advisable to stick it into neutral

a bit of interesting news for you though that is along the same lines:

the old routemaster buses were notorious for blowing up torque converters, something in their design meant that when they got hot, they exploded, so the mechanics drilled holes into the torque converters, plugged them with lead and left them at it

this way the lead melts as the oil gets hotter and blows a hole in it, simple to replace the lead plug rather than the whole torque converter

centrecom also made sure that drivers were reminded to put the buses into neutral when stuck in traffic