A signaller controlling level crossings has a responsibility for balancing rail and road operations. Every time road users are held for unnecessarily long periods when the railway signalling would perfectly safely permit otherwise, they are more and more likely to 'jump the lights' next time.
I do very much agree with the latter part of this, and stand by my earlier post - I very much believe that excessively long closure times do, over time, increase the likelihood of misuse. Yes, it's illegal to jump the red lights, and I've reported more than a few for doing so - but I consider it far more productive to try to keep them on side in the first place, so that they're perhaps less likely to do so!
I also
know that different signalmen work crossings in slightly different ways, in terms of the time at which they start the sequence where (as in the majority of cases) this isn't specified - this is quite reasonable too, where the sequence is started
x minutes after receiving 'train entering section' where
x varies depending upon the type of train and that individual signalman's style. Workload plays a part too - sometimes it's necessary to get the barriers down sooner than normal, because you know that you're going to be busy at the other end of the panel, or on the phone to go through the details for a possession for example, and you don't want to be distracted and cause a delay as a result.
I'll usually raise them briefly if I can, especially at our busiest crossing right in the middle of a town, to try and clear at least some of the traffic - sometimes, to show their gratitude, they'll then end up queued back over the crossing and prevent me from lowering them when I need to. The motorists who get stopped when the barriers go down again seem to get even angrier if they've seen them go up and back down before they've had chance to get across - ignoring the fact that doing so has at least cleared some of the traffic, thus easing their passage when the second train's passed. I can see, then, why so many are reluctant to go for a quick 'swing'!