While another widely stated benefit of low floor buses is quicker boarding for able-bodied passengers due to the lack of steps, studies have found the opposite effect in the UK. This is apparently due to the prevailing system of operation where passengers enter and exit through one single front door. It has been suggested that the previous 1980s/90s high floor step entrance buses which featured a centre rail, encouraged a bi-directional flow of entering and exiting passengers simultaneously. The removal of the pole to allow wheelchair/buggy access created the situation where the quintessentially polite British bus passenger would wait for all passengers to alight before boarding, leading to an increase in dwell times.