Its not only weight but many taxis here have a portable ramp that is too steep and too long. And reversing out means the chair will tip, even if you are able to steer accurately enough to stay on it. So you have to rely on an unexperienced driver to prevent it tipping over while you are 3 feet in the air. They wont do it, and I wouldnt let them.
This is one of the less steep ones. Still very dangerous reversing out.
https://www.wheelchairdriver.com/images ... medium.jpgThis one is ALMOST accessible, but still too steep for stability in a rear drive chair. And with a 192kg chair it will not climb that ramp with a 20 stone use even if it doesent tip you out (but it does!). They fit ramps so that they comply with the law. Around 80% of them are too short, too high, too steep or no space inside to turn around. This one is one of the better ones.
https://www.wheelchairdriver.com/images ... mp-700.jpg But too steep. Also not enough headroom. But it complies with the law that the taxi driver cares about. The fact that you cant get in just saves him the effort and time as you wont call again.
Then theres the ones that use these.
https://c8.alamy.com/comp/B2N259/taxi-d ... B2N259.jpgBut the Q700 for e.g has its caster wheels MUCH NARROWER track than the rear wheels. So it literally doesent fit!
They are all visualising someone in a manual chair that can stand or move around. And they have ramps accordingly. I gave up on them. Thats why I ave a proper van, lowered floor so that theres enough headroom. (thats another problem. They are not tall enough inside in some cases either! No lowered floors.
So problems include far too steep, so safety or lack of traction/torque to climb the ramp, and needing someone to prevent it tipping over backwards. Not enough head room. And so safety. Literally inability to get in. And not enough headroom. As well as the drivers just not wanting the trouble.