They are typically moving between 0 and 1 passenger around -- worse than cars.

Multi occupancy - its actually more cost effective for a group of 4 or 5 to jump in a Cab for a short trip than to use the underground.

So you would argue that bus lanes should be HOV lanes - if you have at least 3 people in your car you can use it (although if it's a taxi, minimum would be 4 people)

I can't speak for London, but in my experience, cabs are more likely to have a single passenger, than cars are to have a single driver.

And your point is exactly what

Given that cabs typically have 1 passenger in, why should they be allowed in bus lanes?

I was making the point that the responder had no experience of London cabs.

And its common for groups to use cabs in London and also for those with heavy luggage or who are disabled Black cabs a re a godsend in London