If you want to be efficient in Amsterdam, you take the bike or public transport. That has been faster than cars even before this change, and now more so.
It is terrible. They introduced similar speed limits in parts of London UK and it sucks. It does help with noise pollution but driving in London on empty roads at 20 mph is horrible.
It also happened in Portland in 2018, and it sucks, and makes me avoid Portland.
The speed limit is 20mph on most roads, no matter how many lanes of empty tarmac there is, what time of day it is, with how much visibility, how straight the road is, etc. It's a blind political statement with no regard to the actual roads and their circumstances.
It can be a political statement, or it can be about noise and pedestrian safety, depending on the environment.
Basically, it's irresponsible to drive faster than 30 km/h anywhere with a significant number of pedestrians. The risk of serious injury and death rises quickly above that speed, and human drivers cannot react quickly enough at higher speeds. You can justify a bit higher speed limits on major streets with significant traffic, as pedestrians tend to be more attentive when crossing them. But even then, the limit should be 40-50 km/h, as road capacity decreases and noise level becomes unacceptably high at higher speeds.
Because the tarmac is empty does not mean the people and nature living around the roads are gone. Whenever resource sharing with other living creatures pops up in America it somehow gets turned into a 'blind policital statement'.
If you want to reduce the number of cars on roads - which is a sensible approach - you reduce the need for cars. The easiest is to not mandate people to work in offices where not needed. By slowing vehicles down you achieve a placebo effect since said vehicles would be slow anyway when there’s traffic, while they’d be needlessly slow when there is none. Spending more time driving slowly means the same amount of noxious gases being emitted - even if emissions per car are lower, given that they spend more time on the road you gain little benefits.
However safety benefits and noise reduction are an asset. But those can easily be reduced in better more environment friendly ways.
Seattle dropped residential speed limits to 20mph some time ago. Havent followed up to see what impact that has had yet... Most roads though still kepts their old speed limits.
What happens in the US when speeds are too low, is you get half the people obeying it, and half of them driving way faster. It creates a dangerous conflict q lot of times. People road rage like crazy in some areas and will do dangerous shit like pass slower cars in unsafe places, tailgate, cut people off, etc.
They haven't put in any road diets in Seattle and the cops aren't enforcing traffic laws so everyone just drives the way they used to. So you've got 25 mph limits on 4-lane stroads with no pedestrian traffic (like literally no sidewalks in one case I can think of) and everyone does 45 mph.
It looks like they're going to start using speed cameras now instead of police enforcement (they certainly don't want to use police enforcement here, that would clearly turn out badly). They're trialing "racing cameras" to supposedly catch the kids drag racing at night, but it is obviously a way to introduce enforcement of the 25 mph limits without doing road redesign and to generate revenue.
The result is pretty obviously going to be regressive taxation, because Seattle/Washington State runs everything via regressive taxation. So the traffic cameras are not being setup on W Seattle Bridge to catch white collar people commuting to the office, but are put on W Marginal Way which are going to catch blue collar workers.
I'm just waiting for liberal Seattle to wake up one morning and realize the DOT is funding their bike lanes by regressive taxation through traffic camera enforcement, falling on the lower class and minorities, and see if their heads explode or not.
There's a way to do it right like Amsterdam where they've already built all the infrastructure and done all the road diets, we're doing it the ass-backwards way by dropping the speed limits and setting up traffic cameras.
