The capacity of a road in the United States is about 2100 vehicles per hour per lane. Driver behavior affects this somewhat – it's 2600 in Europe. I'm wondering if that 2100 is actually slightly higher in the Boston area. Here are two pieces of evidence:
This thread (https://www.aaroads.com/forum/index.php?topic=20217.msg2304871#msg2304871) lists the busiest 2-lane roads. As you can see, very few states have any over 30,000 AADT. While that list only gives one per state, Massachusetts has at least three (data is pre-COVID): MA 125 between I-495 and the New Hampshire border in Haverhill, MA 12 in Leominster, and US 3 just south of I-95 in Burlington. While having traffic in the middle of the night would increase AADT without decreases caused by congestion, none of these roads would seem to have this, so it's either caused by more efficient drivers (my hypothesis) or every other state 4-laning anything that gets anywhere close to 30,000.
My other piece of evidence is that most of the country has left lane hogs, you know, the ones that stay in the left lane of a freeway going the speed limit or even under the speed limit. That doesn't happen here. There are slow drivers, but they stay in the right lane. Trying to be a left lane hog will get you run over. In addition, the law that trucks must stay in the right two lanes of a freeway is pretty well followed.
Does anyone else have any evidence to support or reject it, or have comments about any other part of the country (or world)?
The problem is, those three stretches of roadway are pretty terrible at peak hours. US 3 at the Woburn/Burlington border is a slog much of the day, MA 12 in Leominster has significant backups all day, and MA 125 in Haverhill in the evening is absolute gridlock.
All of these roads I have cycled in during peak traffic and I can easily outpace the traffic, in Leominster over a stretch of two miles (I used to live in Fitchburg so it was a common occurrence for me). I would not consider them efficient at all. Some with less traffic, like MA 38 in Woburn I can outpace traffic from Winchester to Wilmington, a four-mile stretch. And I'm no speedster...
And one refute on trucks, on the eight-lane freeways, where trucks must stay out of the left two lanes, in reality they only stay out of the far left.
Hm. Congestion as "efficiency." Interesting concept.
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
When I first moved to Metro Detroit a few decades ago, I noted that we have rush hours and traffic jams. We're just not sensible enough to slow down for them. 70 mph with only 1 car length separation. That must be "efficient".
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
All other things being equal, twice as many vehicles on a road filled to maximum capacity can cross the same point at 70 mph than traffic moving at 35 mph. All other things aren't equal, but the real world rarely matches the theoretical best.
Quote from: skluth on February 26, 2022, 03:35:39 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
All other things being equal, twice as many vehicles on a road filled to maximum capacity can cross the same point at 70 mph than traffic moving at 35 mph. All other things aren't equal, but the real world rarely matches the theoretical best.
Pointing out the somewhat obvious here, but one of the things that isn't equal is that following distance increases at higher speeds. Another is that higher speeds are harder for entering traffic to match.
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
This makes some sense. Running a red light repeatedly while only cutting someone off 10% of the time you do so will reduce congestion on the roads on average, but that 10% will definitely be remembered as bad driving by whoever else was in the intersection at the time. (And the tradeoff here isn't worth it, due to more likely crashes.) The same is true for aggressive left turns from parking lots onto busy roads, which, unlike running a red light, isn't illegal.
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
No Turn On Red signs are seen as optional to many. Which is really frustrating for people who design roads. So, now we add in things to force people to make turns very slowly.
iPhone
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
The problem is that Boston drivers drive way faster than they should. US 1 north of Boston basically becomes like the Autobahn during peak travel times, because there may be someone in a tricked out Civic zigzagging between cars.
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
There are drivers here that will merge onto the freeway at 55mph and then immediately camp in the center or left lane at that speed. It's obviously out of instinct.
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
But it minimizes required pavement and somewhat reduces gas consumption
Actually, 35 is pretty unstable as at that point things can collapse to congested flow to a total loss of throughput, but lower speeds (not speed limits!) during rush hour definitely help to handle more traffic.
Quote from: kalvado on March 01, 2022, 01:18:31 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
But it minimizes required pavement and somewhat reduces gas consumption
Actually, 35 is pretty unstable as at that point things can collapse to congested flow to a total loss of throughput, but lower speeds (not speed limits!) during rush hour definitely help to handle more traffic.
See my first sentence again.
Quote from: Rothman on March 01, 2022, 01:22:20 PM
Quote from: kalvado on March 01, 2022, 01:18:31 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
But it minimizes required pavement and somewhat reduces gas consumption
Actually, 35 is pretty unstable as at that point things can collapse to congested flow to a total loss of throughput, but lower speeds (not speed limits!) during rush hour definitely help to handle more traffic.
See my first sentence again.
Well, let's separate "efficiency" as defined by Rothman-the-Driver and as defined by Rothman-the-DOT-employee.
There is really a point where improving individual efficiency costs too much for everyone. That can include direct cost of pavement, indirect things like environmental and society implications and so on. A lot of discussions about "should we build this and that" actually come down to that balance in some way.
So while I am not too willing to accept 35 MPH highway cruise speed as new normal (for interstate grade road, maximum throughput is 45-50 MPH anyway), going as low as speed limit on Northway may be a sort of accepted deal.
Quote from: webny99 on February 26, 2022, 09:23:24 PM
Quote from: skluth on February 26, 2022, 03:35:39 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
All other things being equal, twice as many vehicles on a road filled to maximum capacity can cross the same point at 70 mph than traffic moving at 35 mph. All other things aren't equal, but the real world rarely matches the theoretical best.
Pointing out the somewhat obvious here, but one of the things that isn't equal is that following distance increases at higher speeds. Another is that higher speeds are harder for entering traffic to match.
I've been in enough rush hour traffic in large cities to know your statement is only true as far as safety goes, not real world experience. It also leads to lots of fender benders, but the safe distance between vehicles in rush hour traffic and the reality of rush hour traffic distance spacing are two entire different values. Spacing also (theoretically) becomes a lot less important if we transition to fully autonomous vehicles.
Quote from: skluth on March 01, 2022, 05:42:48 PM
Quote from: webny99 on February 26, 2022, 09:23:24 PM
Quote from: skluth on February 26, 2022, 03:35:39 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
All other things being equal, twice as many vehicles on a road filled to maximum capacity can cross the same point at 70 mph than traffic moving at 35 mph. All other things aren't equal, but the real world rarely matches the theoretical best.
Pointing out the somewhat obvious here, but one of the things that isn't equal is that following distance increases at higher speeds. Another is that higher speeds are harder for entering traffic to match.
I've been in enough rush hour traffic in large cities to know your statement is only true as far as safety goes, not real world experience. It also leads to lots of fender benders, but the safe distance between vehicles in rush hour traffic and the reality of rush hour traffic distance spacing are two entire different values. Spacing also (theoretically) becomes a lot less important if we transition to fully autonomous vehicles.
While 2 seconds is recommended timing, numbers for free flow traffic are given as 45 vehicles per lane-mile. That is 1.3 seconds at 60 MPH on average, or 2400 vehicles per hour. You're probably thinking congested flow, where speed cannot be maintained.
(https://www.researchgate.net/profile/Srijith-Balakrishnan/publication/287206999/figure/fig4/AS:669485472174098@1536629183645/Speed-flow-curves-and-LOS-for-multi-lane-highway-segments-Source-Highway-Capacity_W640.jpg)
Quote from: skluth on March 01, 2022, 05:42:48 PM
Quote from: webny99 on February 26, 2022, 09:23:24 PM
Quote from: skluth on February 26, 2022, 03:35:39 PM
Quote from: Rothman on February 26, 2022, 12:21:00 PM
Quote from: 1 on February 26, 2022, 12:11:14 PM
Quote from: Rothman on February 26, 2022, 12:09:08 PM
Hm. Congestion as "efficiency." Interesting concept.
This is actually true. The maximum flow on a freeway happens at about 35 mph; I'm not sure what it is on two-lane roads.
By only one definition of efficiency. If it's taking me twice as long to get somewhere, but capacity is maximized at a lower speed, that's not my sense of efficient.
All other things being equal, twice as many vehicles on a road filled to maximum capacity can cross the same point at 70 mph than traffic moving at 35 mph. All other things aren't equal, but the real world rarely matches the theoretical best.
Pointing out the somewhat obvious here, but one of the things that isn't equal is that following distance increases at higher speeds. Another is that higher speeds are harder for entering traffic to match.
I've been in enough rush hour traffic in large cities to know your statement is only true as far as safety goes, not real world experience. It also leads to lots of fender benders, but the safe distance between vehicles in rush hour traffic and the reality of rush hour traffic distance spacing are two entire different values. Spacing also (theoretically) becomes a lot less important if we transition to fully autonomous vehicles.
If you're saying that spacing
doesn't increase at higher speeds, I don't buy that at all. You might have traffic following too closely at a range of different speeds, but too close at 35 mph and too close at 70 mph are still very different things. Even if it following distances are still "too close" at higher speeds, meaning it's no
safer, there's simply no way the average following distance doesn't increase as speed increases.
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
CT is worse. My take was always that MA drivers are fearless, CT drivers are reckless.
Quote from: spooky on March 01, 2022, 08:12:12 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
CT is worse. My take was always that MA drivers are fearless, CT drivers are reckless.
Amen, brother.
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Quote from: spooky on March 01, 2022, 08:12:12 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
CT is worse. My take was always that MA drivers are fearless, CT drivers are reckless.
Miami: "Why not both, plus ignorant?"
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Quote from: Rothman on March 02, 2022, 12:02:28 AM
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Overinsured? One of the most basic truths of auto insurance is that level of insurance decreases with driving skill. Irresponsibility is consistent across both driving and being financially responsible.
(And this isn't a poverty thing. I can't believe how many claims I adjusted where someone's expensive car came with rather low liability limits).
Quote from: SectorZ on March 02, 2022, 08:37:41 AM
Quote from: Rothman on March 02, 2022, 12:02:28 AM
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Overinsured? One of the most basic truths of auto insurance is that level of insurance decreases with driving skill. Irresponsibility is consistent across both driving and being financially responsible.
(And this isn't a poverty thing. I can't believe how many claims I adjusted where someone's expensive car came with rather low liability limits).
Pfft. CT is where a whole bunch of insurance companies are headquartered. I am sure the thousands of employees have some sort of benefit in terms of cheap, good insurance.
Quote from: Rothman on March 02, 2022, 12:02:28 AM
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Key part of the statement there. :D
Quote from: RobbieL2415 on March 01, 2022, 10:42:00 AM
There are drivers here that will merge onto the freeway at 55mph and then immediately camp in the center or left lane at that speed. It's obviously out of instinct.
This is a very common thing in Connecticut. It's even worse when they get in the left lane to pass a truck, but then go the exact same speed as said truck. This is especially common on I-84 between Danbury and Waterbury.
Quote from: Rothman on March 02, 2022, 09:45:57 AM
Quote from: SectorZ on March 02, 2022, 08:37:41 AM
Quote from: Rothman on March 02, 2022, 12:02:28 AM
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Overinsured? One of the most basic truths of auto insurance is that level of insurance decreases with driving skill. Irresponsibility is consistent across both driving and being financially responsible.
(And this isn't a poverty thing. I can't believe how many claims I adjusted where someone's expensive car came with rather low liability limits).
Pfft. CT is where a whole bunch of insurance companies are headquartered. I am sure the thousands of employees have some sort of benefit in terms of cheap, good insurance.
Most carriers give their employees a 10% discount. Not very lucrative.
Quote from: SectorZ on March 02, 2022, 10:28:37 AM
Quote from: Rothman on March 02, 2022, 09:45:57 AM
Quote from: SectorZ on March 02, 2022, 08:37:41 AM
Quote from: Rothman on March 02, 2022, 12:02:28 AM
Quote from: froggie on March 01, 2022, 10:24:00 PM
Quote from: Rothman on February 28, 2022, 11:43:46 AM
Quote from: tylert120 on February 28, 2022, 08:21:20 AM
I worked in Boston for 8 months. I'm just here to say Boston drivers may be "efficient," but they are definitely some of the worst drivers in America.
Meh. CT is worse.
Disagree. CT drivers, like NY, are predictable. MA drivers are anything but.
Nah. I grew up in MA. CT drivers give a bad name to the entire Northeast. Keep an eye out for those telltale blue plates and you'll see how they've infected everywhere with their overinsured bad driving.
Overinsured? One of the most basic truths of auto insurance is that level of insurance decreases with driving skill. Irresponsibility is consistent across both driving and being financially responsible.
(And this isn't a poverty thing. I can't believe how many claims I adjusted where someone's expensive car came with rather low liability limits).
Pfft. CT is where a whole bunch of insurance companies are headquartered. I am sure the thousands of employees have some sort of benefit in terms of cheap, good insurance.
Most carriers give their employees a 10% discount. Not very lucrative.
Let me rephrase: It was a joke. :D
My dad avoided I-95 through Boston in 2012 for these reasons. He opted for I-495, to stay away from the city.
Quote from: epzik8 on March 02, 2022, 05:30:12 PM
My dad avoided I-95 through Boston in 2012 for these reasons. He opted for I-495, to stay away from the city.
Pretty easy to avoid a road that was never built... ;-)