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Re: Pedestrians aren't the only ones who matter.

Posted by R30A on Fri Feb 3 13:15:30 2017, in response to Re: Pedestrians aren't the only ones who matter., posted by BrooklynBus on Fri Feb 3 11:19:26 2017.

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"If the signals are in fact timed for 30 mph, yes. If not, no,the average speed will not be 30 mph."
Yes what? Your comment says nothing and does not refute what I stated.

Yes, if the signals were timed for 30 MPH, reducing the speed limit would likely reduce the average speed. If they are already timed for 25 MPH or lower, lowering the speed limit would do nothing.

"You cannot assume volume will remain the same, nor can you assume that capacity will go down."

I used the incorrect word. I meant throughput, not volume. Ask any engineer. They will confirm when you lower the average speed, you lower the throughput, meaning the number of vehicles that can cross the intersection in a traffic cycle.

Speed is simply one variable. If you lengthen the cycle or the proportion of the cycle for which the road in question has a green signal, that can easily not be the case.


"(You would probably miss an additional light.)
Baseless assumption."

That is exactly what lowering throughput means. Since fewer cars get through, they have to stop more often.

If you assume that they were previously timed for the higher speed, and you assume that the cycles otherwise remain the same, then yes. But now we are requiring many assumptions for what you claimed was a universal truth.


"Your average speed is now reduced from about 28 mph to about 21 mph.
Fabricated numbers with no basis in reality."

No. They are realistic numbers. If you disagree, what would you say they are?

I am an honest person, so I do not fabricate data and claim it as fact.

"THEREFORE EVEN UNDER THOSE OPTIMAL CONDITIONS, YOUR AVERAGE SPEED IS STILL LOWER WHEN YOU LOWER THE SPEED LIMIT.
This is not a universal truth, as I have repeatedly been saying."

Yes, you have repeatedly been saying that, but you haven't shown that is the case. Even the singular example exception you gave after finally admitting that in general lowering the speed limit does lower the average speed is incorrect. Now what are you going to do. Deny you said that? And ask me for the reference? I will not go around in circles with you.

My statement has not changed. Lowering the speed limit does not universally result in a lower average speed. Nothing you have said disproves that statement. In fact, your long list of assumptions that you have to make outright proves it.

Me: The only situations where lowering the speed limit does not effect the average speed is (1) if there is so much traffic that you cannot travel at the speed limit anyway and (2) no one is abiding by the new lower speed limit anyway.

You: Or if, as I have been saying all along, road conditions make the higher speed limit unattainable for some reason.

That was never the issue.

That was ALWAYS the issue.

Me: It is obvious that those two situations were taken out of the equation from the beginning and please don't tell me they weren't even if I didn't specifically mention it.

Maybe not the beginning, but early enough that they are certainly not what I am referring to. But yes, before you mentioned them, both are certainly perfect valid counterexamples for why lowering speed limits does not necessarily lower average speed.

IT WAS ASSUMED, just like No stopping on highways does not mean you should hit the car in front of you when it comes to a stop on the highway because of traffic.

You: Which brings up another good example of why the universal statement is wrong. If higher speeds result in a far greater number of accidents resulting in gridlock, average speed could certainly go up with a lower speed limit.

For that to be the case, reducing the speed limit by five miles per hour would have had to reduce the number of accidents by a HUGE amount like 80 percent.

80%? Proof? But who said anything about 5 MPH? I am certain there are places where lowered speed limits does reduce the number of accidents by 80%.

The numbers are probably not more than a couple of percentage points.
In general, that is almost certainly true.

And we are not only talking about accidents involving pedestrians. Would you say there has been a dramatic decrease in the amount of fender benders since Vision Zero? I have not seen any statistics that indicate that. Have you?
What does this have to do with this discussion?

Me: So discounting those two possibilities, there are no circumstances where lowering the speed limit doesn't lower the average speed. EVEN THE EXAMPLE YOU CITED IS INCORRECT.

You: One of those two possibilities is an example of why, but isn't the general reason why the statement is false. Lowering the speed limit will not reduce the average speed, if the old limit was unattainable for any reason. That could be traffic, signals, road condition, road layout, etc. Anything whatsoever.

As I already stated, that is not the issue. The entire discussion was based on conditions when driving at the speed limit was achievable. We were not talking about times when speed is limited by congestion and not the speed limit. as I said, THAT WAS OBVIOUS. Thanks for trying to divert the discussion once again.

Amazing how stubborn you are. You just cannot admit when you are wrong.

It is amazing how many times you try to change what we are talking about to make it into a discussion in which your statement is right. And you call me stubborn???

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