alt Hacker News>driving enough below the limit that they won't accidentally exceed it
That is precisely why traffic would effectively grind to a halt. Because going even 0,0001 over the limit is so easy, you would have to turtle through traffic to get anywhere while making certain you never go above the limit. 50km zone is now 30km, and you didn't decelerate quickly enough and were going 32km at the threshold. 60km zone, but you accelerated too quickly and hit 61km for a moment. And sometimes, rarely, but sometimes you have to accelerate yourself out of a dangerous situation.
Honestly if you are arguing for this idea, I strongly suspect you have no experience driving. I've driven for about 25 years. I've received two speeding tickets. One in Germany (I'm danish), where I got confused due to unfamiliar signage and got dinged for going 112km in a 100km zone. And once here I got a ticket for going 54 in a 50 - my mom was at the hospital, possibly about to die (she didn't). Both of those were speed traps.
How close to your desired speed are you able to maintain?
> 50km zone is now 30km, and you didn't decelerate quickly enough and were going 32km at the threshold.
Is the argument that you and others would be unable to safely achieve the posted speed within the speed limited area? For example, if you feel you can't drive more precisely than 40-50 when you are aiming for 45, in the above scenario, you could start with your goal being 45, then in the 30 zone aim for 25, knowing that you'd be going no faster than 30 when your intend to drive 25.
> 60km zone, but you accelerated too quickly and hit 61km for a moment.
Should you aim for 55, if for example the most precise you can do is +/- 5? Or adjust correspondingly for how precise you are able to keep within a desired range.
And of course:
* In a world where enforcement was more consistent, we might expect speed limits to eventually be adjusted - i.e. are speed limits currently set lower than what is technically safe because we assume that some portion of people will currently break the law?
* With self-driving, or at least automated speed-keeping (but not steering) there will no longer be the issue of someone having the problem of being unable to stay within x km/h of the speed they're targeting.