That bridge is clearly designed in that way to comply with the ADA.

Injecting my personal politics: I've always thought the ADA was a somewhat misguided initiative when it comes to wheelchair accessibility. Seems like if we had taken all the money we spent trying to make places accessible by wheelchair and had instead directed it towards R&D for better modes of assistance for the disabled, we might've solved the problem instead of just slapping a bandaid on it.

Plus we wouldn't have bridges like this, which are worse for the non-disabled.