Good for you Erin, and I agree that many of us know when we can drive and when we can't, it is a personal decision as long as we aren't hopped up on pain killers or drinking away our pains. Even if we are struck with sudden weakness it is still extremely possible to safely move the vehicle out of the flow of traffic even if that weakness takes our ability to apply the break, say at an intersection crossing, vehicles are still equipped with emergency breaks, that if slowly applied and not yanked on like your 'drifting' act in the same way as the pedal break.
Conscious drivers know this, and honestly the complaints Erin has described concerning pushing herself to drive are no different than any number of potential vehicle malfunctions, only in this case it was physical malfunctions with the driver, but at no point was her mental accurity compromised.
When many officers complain about people continuing to drive past their ability it is those with dementia, cataracts so bad they cannot see clearly or when filled with so much anxiety that they simply cannot react, when it comes to medical, and then of course there are still the druggies (legal or not) and the drunks filling our highways.
I still drive, proven by being in an accident last week, but it wasn't me who caused the wreck, it wasn't one I could have avoided either, even in tip-top perfect health, and the lady who hit me couldn't even blame MS or even a cell phone on simply not paying attention. Accidents do still occur even without any medical or drug induced impairments.
And even after the accident I still choose to drive, a manual transmission without hand controls at that. What has to happen? What cost has to be paid to the public at large for me to get off the roads? Nothing... Answers both questions, when I go out to my car and can't engage the clutch, DH gets a text to pick something up, or mom gets a call to take me somewhere. But then I can do that.
However if DH is out of town, DM is tied up at work and there's an immediate need for me to get behind the wheel, I still do, forcing the leg through pain and weakness to engage the clutch, utilizing cruise control whenever possible and yes every so often dropping to neutral and using EB as my breaks.
I'm not driving erratically, I'm still perfectly capable in reacting to kids running out into my path (neighborhood's feral children love playing chicken with the cars) and pretty much until my body tells me it's my limit, or the doctors/DMV insist it is my limit (which I will likely stop long before then) I will continue to drive.
And honestly I'm a bit amazed at the preachy quality this thread had taken, as we all know, or should be aware, that MS strikes us down in any numerous ways, and just because some symptoms might be similar that one is experiencing doesn't mean that they necessarily had all the contributing factors another experienced when making the tough choice to give up what remaining independence another had.
Though Erin I both applaud you for getting a taxi when needed, but do think you could be a bit more firm with the folks, though that's mostly by the sound of their age and health conditions, you've reached the unfortunate point of now needing to be the parent, try not to spoil them too much