There are barriers that restrict traffic based on dimensions - such as the 'bus trap' [1] that only allows wide vehicles, and the 'sump buster' [2] that only allows high-ground-clearance vehicles through.
Of course, these have the disadvantage that (a) they damage the cars of confused motorists [6] (b) cars stuck in traps obstruct busses anyway[5], and (c) large SUVs and pick-up trucks can drive over them anyway [4].
Another option is a powered rising bollard [3] or barrier together with some mechanism (tag, ANPR, keypad) for recognising authorised vehicles. Which avoids a lot of those weaknesses - at the cost of power and maintenance.
Of course, these have the disadvantage that (a) they damage the cars of confused motorists [6] (b) cars stuck in traps obstruct busses anyway[5], and (c) large SUVs and pick-up trucks can drive over them anyway [4].
Another option is a powered rising bollard [3] or barrier together with some mechanism (tag, ANPR, keypad) for recognising authorised vehicles. Which avoids a lot of those weaknesses - at the cost of power and maintenance.
[1] https://en.wikipedia.org/wiki/Bus_trap [2] https://en.wikipedia.org/wiki/Sump_buster [3] https://goo.gl/maps/epSrQ2641m6ccf6cA [4] https://www.bbc.co.uk/news/uk-england-northamptonshire-22352... [5] https://www.manchestereveningnews.co.uk/news/greater-manches... [6] https://www.abc.net.au/news/2018-08-22/car-blocks-o-bahn-for...