spare_wheel

25 mph speed limit takes effect Friday in New York City
The lower speed limit law was signed last week by Mayor Bill de Blasio as a key part of the mayor's Vision Zero plan to eliminate traffic-related deaths.

https://news.yahoo.com/video/25-mph-speed-limit-takes-105858854.html

There is little question that driving at lower speeds and especially at speeds *below* the speed limit dramatically decreases injury crashes:

https://www.nhtsa.gov/people/injury/e...s/ferguson.pdf.

25 mph as the default is a good first step but I think 20 would make far more sense based on this:

Literture Review on Vehicle Travel Speeds and Pedestrian Injuries

I suspect cycling mode share would skyrocket if urban areas had a default 20 mph speed limit on non-limited access roads. Hopefully, people start prioritizing safety, health, and livability over the transient convenience of motoring at high speeds.

illdoittomorrow

As always, the comments are good for a laugh... liberals overregulating my life! Socialism! Marxism! Your not the boss of me and you can't make me! People (i.e., me) never obey speed limits anyway! Revenue!

No mention of Agenda 21 or being sent to the FEMA camps yet, but give it time.

CharlyAlfaRomeo

If there is a ton of enforcement people will slow down but if the enforcement doesn't continue speeds will rise again.

Studies have shown that humans in absence of law enforcement will drive as fast as they feel they safely can, regardless of the speed limit.

spare_wheel

Not always. In dense urban centers traffic signals can be reconfigured to increase compliance. For example, downtown portland has signal timing that pretty much makes it impossible to drive over 17 mph (although some idjits still try).

unterhausen

this is why I want the campus I work on to install a speed table at every crosswalk. Tired of dodging speeding cars. I regularly drive through a small town in West Virginia that apparently has good speed limit enforcement. Nobody speeds there

prathmann

This is especially effective when there are signs indicating the speed to go to get all green lights. E.g. I remember a German town with speed limit signs saying 50 km/hr but also 'Green Wave - 45 km/hr'.

B. Carfree

IF the people are observant enough to make the connection. I remember driving a delivery truck in Corvallis a few years back when the signals through downtown were set such that at 20 mph one sailed on down the road. I didn't know whether to laugh or cry as the overwhelming majority of the motorists tried ever so hard to go thirty miles per hour. They would slam on the brakes, wait for the green and jam on the gas, followed by slamming on the brakes, rinse and repeat, all the while oblivious to those few of us who just rolled along at twenty.

Of course I was a bit jealous since the corresponding streets in Eugene have the signals set to require one to exceed the speed limit in order to roll through without stopping. I'd rather have stupid people slamming/jamming than have stupid traffic engineers facilitate dangerous driving.

kickstart

Traffic engineers use what's called the 85th percentile to set speed limits. Its the actual observed average speed 85% of drivers go on a particular road.

CharlyAlfaRomeo

That's engineered traffic calming and wasn't covered by my previous post. Of course there are ways to slow drivers down without enforcement, I never said there wasn't.

There are better ways than just changing the traffic signals, ways that would be a lot less frustrating, less polluting and more bicycle friendly though they cost more than reprogramming the lights.

spare_wheel

Word.

spare_wheel

It's hard to read between the lines when someone makes a generic statement. (Did not intend to be argumentative.)

B. Carfree

Well, that's the 85th percentile of independent vehicles. (When ten are stacked up, only the lead vehicle chooses the speed.) Also, they are allowed to lower the speed limit from that level if circumstances warrant it. Among the factors that are supposed to be considered are the presence of cyclists and pedestrians as well as the crash history (now irrelevant since police reports are only taken if someone dies or takes an ambulance ride). Unfortunately, far too few of our traffic engineers are interested in safety, as demonstrated by our horrific numbers of injuries on our roadways.

kickstart

I was simply pointing out a fact about observed speeds, and how they are used without offering any personal speculative interpretations.

Trying to blame traffic engineers for the actions of road users who cause most of the "horrific numbers of injuries on our roadways" by ignoring the efforts of said engineers, and their obligation to observe the collective intent of traffic laws doesn't hold water.

We're all part of the problem....even as cyclists....and it won't change until we're all willing to admit it.

Coal Buster

My experience in planning is that traffic engineers do what their clients pay them to do. When designing access roads for a new megastore, for example, they will design them for the maximum advantage of the store within the law. It is up to the governing body to modify those plans to fit the community. Planning boards will often deny things that are perfectly legal but deemed too dangerous for the community, like left turns out of driveways onto busy roads. The planning board operates under the guise of the Master Plan. A master plan establishes the framework and longterm goals for a community. The master plan contains no rules but is the basis for the rules that follow. If the law is the teeth, the master plan is the gums. The upshot of all this is that the traffic engineers are at the bottom of this process. Attacking them is pointless. If you want to make bicycling safer in your community, it has to be addressed in the master plan. If it is, then every agency has to work towards, or at least heed, the effect of traffic on bicyclists. If not, then cyclists just fall under the general "welfare of the community" aspect of planning, which means that bicycle safety is not in the forefront, or at best, barely considered, when designing town roads.

Looigi

That implies raising the speed limit, say to 80 mph so that everybody is below it, would increase safety....?

I say that facetiously of course, but the point is that speed limits are just numbers posted on signs, what's relevant is driving speeds appropriate to the conditions irrespective of what's posted. What's appropriate, of course, is a matter of opinion. Personally, I very rarely find my self troubled by the speeds most drivers drive, unless it's slower than I want to go and they're holding me up.

Coal Buster

I disagree. The lower the speed the less likely an accident will be fatal. At 25mph, pedestrian survival is likely; at 40mph, death is more likely. The difference in energy goes as velocity squared. Even a small increase in speed will be a large increase in total energy. The point is that there will be plenty of accidents even if drivers are driving at "appropriate" speeds. The goal of the reduction in speed is that a certain amount of accidents are inevitable. Lower speeds=less fatalities.

phoebeisis

It can be very easy-and cheap-to enforce a speed limit.
You can easily use RedLight Traffic cameras to do it-no problem.
Generally they are set to trigger a "ticket" at 6 mph or so above the limit.
So enforcement wouldn't be a problem.
Now getting cabbies and everyone else to agree to 20 mph-could be a problem..
On a side note- Fuel economy-highway FE especially-improves "A lot" at slower-but reasonable speeds.
For example the Ram 1/2 ton pickup 3.6 V6 300 HP 8 speed Auto Transmission is EPA-ed at 25 mpg hy
But at a steady 60 mph(reasonable speed) you will get an honest 30 mpg- yeah 5000 lb blocky vehicle will beat HY EPA by 20 % by just driving a reasonable 60 mph
Same story for the Ram 3.0 TD- EPA 28mpg but delivers 40 mpg at 60 mph

Now city EPA is a different story-but lower speeds won't hurt mpg- IF the lights are correctly timed
Waiting at lights-with the motor running-Kills efficiency/MPG/FE-many hypermilers turn the motor off at redlights
And a large part of the Prius honest 50 mpg city is because it automatically shut the motor off when it isn't required

Yeah speed kills- 20 mph on many streets-would be ok with me-but probably not with many drivers
Hmmm-some bike riders can exceed 20 mph on level streets

25mph is probably about as good as it will get-

A Hi-ish TECH solution to texting while driving would be more likely to be accepted than dropping speed limits
It wouldn't be THAT hard to disable phones while a car is moving-or while the engine is on-heck pretty simple really

Raiden

The simple problem that has kept this from happening: How do you tell if the phones owner is a driver or passenger?

Edit: I didn't know this 25mph rule was happening, I'm all for. Next I want to see all non-commercial car traffic removed from downtown San Francisco

phoebeisis

Who cares? Disable all of them.
But it would be easy enough to slave it to entering the driver's door-the phone that crosses the driver's door becomes disabled when the engine goes on.
But I would have no problem with disabling all phones in running cars.

spare_wheel

i have no problem with high-speed roadways but, imo, they should be limited access, outside of the urban core, and supported entirely by user fees.

steve0257

This for speed limits on streets

keyven

What's to stop the driver from throwing it in from the front passenger side before getting into the driver's seat?

More importantly, mobiles are an integral part of modern life and disabling them for passengers would be incredibly disruptive.

kickstart

They already are "supported entirely by user fees", they're called taxpayers, as everybody benefits from them whether they're direct users or not.

genec

Lowering speed limits will never have enough enforcement... the only practical solution is to redesign roads so that they don't appear like freeways to empowered motorists.

mconlonx

Speed doesn't necessarily lead to more accidents, although it very well might lead to more horrific injuries in the case of accidents.

Tiered licensing would be a better program if we actually gave a damn about human life.

Have any of you ever taken a cab in NYC? There's two speeds: accelerating and braking. Speed at any point of measurement is factored by driver skill/overconfidence vs. length between lights, divided by traffic density. I really doubt a 5mph change of official speed limit will change this at all.