The pre-check line is a great way to streamline the screening checkpoint but unfortunately it's only applicable to the USA. Often the flow at the standard lane is slower due to carry-on luggage screening. It seems the full body imaging goes quicker than the luggage screening, the difference is even greater if it's only the arch metal detector. If we split the lanes between passenger with carry-on luggage (small suitcase and large electronic devices) and the rest (small purse or backpack and no large electronic devices) we may be able to speed up a portion of passengers. Let's assume a worst case of 60% with carry-on luggage, and increase to 70% for people that carry a laptop. Still we have a 30% that may be able to be processed faster at a lane that screens smaller items and requires less time to do so. The machines for small screening items will also be narrower and we could gain some space. This can be applied internationally and also in the US additionally to pre-check depending on each airport statistics.