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Carpool lanes: literally the most important issue of our time!
Feral
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Carpool lanes mostly don't work.
Literally the most important social issue of the 21st century! More important than the Ukraine! More important than global warming or illiteracy or AIDS!
"What do you mean carpool lanes don't work?"
Let me break down two key definitions:
What is a carpool lane?
What do we mean when we say a carpool (or HOV) lane is working?
1) What is a carpool lane?
This is the easy question. A carpool lane is more precisely referred to as an HOV (High-Occupancy Vehicle) lane - this is a lane of traffic (usually, but not always, the leftmost lane on a freeway) where it is illegal by threat of fine for an automobile to travel unless it contains a minimum number of occupants. Most HOV lanes require two-occupant vehicles; some HOV lanes require three-occupant vehicles.
For the purposes of this discussion, we're not talking about related but different restrictions, including toll lanes or HOV access for low-emissions vehicles.
2) What do we mean when we say an HOV lane is working?
This is the more complicated question. Short answer: the primary purpose of an HOV lane is to reduce air pollution. An HOV lane works if it decreases the total number of vehicles on the road over time. It does this by incentivizing carpooling behavior.
Consider the following: a three-lane northbound highway is congested during peak hours (0700-0900 and 1600-1800). The transit agency in control of that three-lane highway has determined that they can add one additional lane, bringing the total to four. Now they are deciding whether the new lane should be an HOV lane or a "normal" (mixed-flow) lane.
If we assume, as a null hypothesis, that an HOV lane does not incentivize carpooling behavior at all, then adding that lane as an HOV lane will be worse than adding a mixed-flow lane. Here's why:
- If the number of existing HOVs is less than 25% of the total vehicle traffic, then you've denied the benefit of an additional lane from the majority of drivers. This means that congestion on the remaining 3 lanes is higher than it would have been if you just added a regular mixed-flow lane. The faster traffic in the HOV lane does not constitute enough vehicles to balance out the increased emissions due to that congestion.
- If the number of existing HOVs is 25% or more of the total vehicle traffic, then the total carrying capacity of the freeway is unaffected. However, traffic has to filter between the HOV lanes and mixed-use lanes, which increases the total number of lane changes, thereby increasing congestion and reducing lane speed, which in turn increases emissions.
Therefore, for an HOV lane to work, it must incentivize carpooling behavior enough to balance out the increased congestion on the other lanes.
The empirical data shows that it doesn't. Usually. Mostly. In some cases it does, a little bit, but those cases are the minority.
If you'd like to read the data, here's a study by Berkeley researchers on the SF Bay Area and another from New Jersey.
Why don't HOV lanes (usually) work?
What the SF Bay Area study found was this: the time-savings of an HOV lane do not motivate enough people to carpool. Some people do convert from single-occupancy to carpooling, but not enough.
They do not go into the reasons for this, but it stands up to common sense.
Carpooling is inconvenient. Instead of driving from your home directly to your workplace, you must drive from your home, to your carpooling partner's home (or a carpool pickup location), to your carpool partner's workplace, and then to your workplace.
Carpooling itself adds a time burden due to these extra stops. It also adds uncertainty - what happens if your carpool partner is late?
Rather, most carpoolers already either live together, or work together, or both. The incentive for carpooling is primarily to save money, not time - if two spouses carpool to separate workplaces, they only need to maintain one car. If two coworkers carpool, they cut their fuel costs almost in half.
How can you make HOV lanes work?
A few ways, but the biggest one is through a combination of public transit and carpooling centers.
Basically, if the carpool driver can pick up all his passengers at a central location (a carpool center or a park-and-ride), and then drop his passengers off at transit stops that are convenient to his commute route, then you've eliminated most of the time-inconvenience of carpooling.
This can also foster a community of carpoolers, so if your driver calls in sick, or your passenger is running late, there are other people at the carpool center who can drive or ride.
The SF-Oakland Bay Bridge is one area where this approach was successful, mostly because SF already had an 'organic' casual carpool community in place before HOV lanes were added to the bridge.
Guess what that means? The answer to traffic is the same as it's always been:
Public transit, public transit, public transit!
Literally the most important social issue of the 21st century! More important than the Ukraine! More important than global warming or illiteracy or AIDS!
"What do you mean carpool lanes don't work?"
Let me break down two key definitions:
What is a carpool lane?
What do we mean when we say a carpool (or HOV) lane is working?
1) What is a carpool lane?
This is the easy question. A carpool lane is more precisely referred to as an HOV (High-Occupancy Vehicle) lane - this is a lane of traffic (usually, but not always, the leftmost lane on a freeway) where it is illegal by threat of fine for an automobile to travel unless it contains a minimum number of occupants. Most HOV lanes require two-occupant vehicles; some HOV lanes require three-occupant vehicles.
For the purposes of this discussion, we're not talking about related but different restrictions, including toll lanes or HOV access for low-emissions vehicles.
2) What do we mean when we say an HOV lane is working?
This is the more complicated question. Short answer: the primary purpose of an HOV lane is to reduce air pollution. An HOV lane works if it decreases the total number of vehicles on the road over time. It does this by incentivizing carpooling behavior.
Consider the following: a three-lane northbound highway is congested during peak hours (0700-0900 and 1600-1800). The transit agency in control of that three-lane highway has determined that they can add one additional lane, bringing the total to four. Now they are deciding whether the new lane should be an HOV lane or a "normal" (mixed-flow) lane.
If we assume, as a null hypothesis, that an HOV lane does not incentivize carpooling behavior at all, then adding that lane as an HOV lane will be worse than adding a mixed-flow lane. Here's why:
- If the number of existing HOVs is less than 25% of the total vehicle traffic, then you've denied the benefit of an additional lane from the majority of drivers. This means that congestion on the remaining 3 lanes is higher than it would have been if you just added a regular mixed-flow lane. The faster traffic in the HOV lane does not constitute enough vehicles to balance out the increased emissions due to that congestion.
- If the number of existing HOVs is 25% or more of the total vehicle traffic, then the total carrying capacity of the freeway is unaffected. However, traffic has to filter between the HOV lanes and mixed-use lanes, which increases the total number of lane changes, thereby increasing congestion and reducing lane speed, which in turn increases emissions.
Therefore, for an HOV lane to work, it must incentivize carpooling behavior enough to balance out the increased congestion on the other lanes.
The empirical data shows that it doesn't. Usually. Mostly. In some cases it does, a little bit, but those cases are the minority.
If you'd like to read the data, here's a study by Berkeley researchers on the SF Bay Area and another from New Jersey.
Why don't HOV lanes (usually) work?
What the SF Bay Area study found was this: the time-savings of an HOV lane do not motivate enough people to carpool. Some people do convert from single-occupancy to carpooling, but not enough.
They do not go into the reasons for this, but it stands up to common sense.
Carpooling is inconvenient. Instead of driving from your home directly to your workplace, you must drive from your home, to your carpooling partner's home (or a carpool pickup location), to your carpool partner's workplace, and then to your workplace.
Carpooling itself adds a time burden due to these extra stops. It also adds uncertainty - what happens if your carpool partner is late?
Rather, most carpoolers already either live together, or work together, or both. The incentive for carpooling is primarily to save money, not time - if two spouses carpool to separate workplaces, they only need to maintain one car. If two coworkers carpool, they cut their fuel costs almost in half.
How can you make HOV lanes work?
A few ways, but the biggest one is through a combination of public transit and carpooling centers.
Basically, if the carpool driver can pick up all his passengers at a central location (a carpool center or a park-and-ride), and then drop his passengers off at transit stops that are convenient to his commute route, then you've eliminated most of the time-inconvenience of carpooling.
This can also foster a community of carpoolers, so if your driver calls in sick, or your passenger is running late, there are other people at the carpool center who can drive or ride.
The SF-Oakland Bay Bridge is one area where this approach was successful, mostly because SF already had an 'organic' casual carpool community in place before HOV lanes were added to the bridge.
Guess what that means? The answer to traffic is the same as it's always been:
Public transit, public transit, public transit!
every person who doesn't like an acquired taste always seems to think everyone who likes it is faking it. it should be an official fallacy.
the "no true scotch man" fallacy.
the "no true scotch man" fallacy.
Feral on
+14
Posts
Also, le gasp, taxes!!! Won't someone think of the job-creating baby jesus?
There are obvious risks, but if can shave the fuel you personally burn by a fair bit.
pleasepaypreacher.net
We have those around here.
There's also talk of priority bus lanes down Broad St (basically the main thoroughfare in Richmond, VA).
And a wild idea about light rail, but that's probably never going to happen.
Did you know Richmond, VA, had the first electric trolley system in the US?
And then we dismantled it because the white people decided they'd rather live in the suburbs, and since, as a Commonwealth, our cities are not funded by the surrounding counties, well why in the world would they want to pay for an efficient transportation system only black and poor people use?
Virginia!
pleasepaypreacher.net
Park and rides are fairly common in the US, but they're also not without their own problems.
The ideal Park & Ride is one that is more like a multipurpose transit center adjacent to a shopping mall, university, or some other city feature that people will want to head to anyway. Then as suburbs turn into exurbs, people taking the reverse commute will get off at the park and ride and walk to that mall/university/etc. Housing in such places will also be higher in demand, which means some people will end up living in walking distance from the park & ride. And it increases ridership on the buses that service that park & ride.
But that rarely happens because that land is expensive, and the usual short-term preference is to build the park & ride where land is cheap. If you're smart, you use tax incentives or permitting to incentivize businesses to move in next to the park & ride after it was built.
the "no true scotch man" fallacy.
pleasepaypreacher.net
All the actual complications aside for carpooling, what about the culture / status-symbol built around car ownership in the country? Speaking as someone who is first generation born in America (out of both sides of the family), my family considers me insane for not owning a car nor wanting to own a car. They see it as a necessity, and have little in the way of real arguments against public transit. But I bring this up to point out another reason why people don't carpool; "I want to drive MY car and if I'm not driving MY car then what's the point of having it?" But there's no consideration of abandonment of owning a vehicle. Cars are something to show off and take pride in. Which would be fine if there wasn't like 2 or 3 per household.
A while back I had to go to the head office in the US for a week. The hotel I was in was 0.5 miles from said office. Even better, right?
Thing is, the only way to get to the entrance is to cross a four-lane highway with no pedestrian features. Not the safest prospect.
So despite being in closer proximity to my destination, the local infrastructure choices meant I had to be in a motorvehicle if I wanted to get there safely.
QEDMF xbl: PantsB G+
We have that in Seattle, they're referred to as "express lanes" instead of HOV lanes though. They work okay. We also have HOV on-ramps -- standard traffic is supposed to wait through single-car traffic lights to enter the freeway/highway during peak congestion hours, but what it really means is that assholes without passengers just abuse the crap out of the HOV ramps.
pleasepaypreacher.net
I've found this infuriating after our move from Hawaii. I used to cycle down to where my wife works, put my bike in her car, then go walking around until she got off work.
Over here I just rode with her since there's no way in Hell I'm going to try and cycle around this area. And when I walked off to try and get downtown I found myself virtually trapped in the area she works because there was literally no way to get in or out without jay walking across four to six lanes of traffic.
I honestly look forward to the day that car culture is relegated to hobbyists with too much money.
they understand they are just raging assholes
nobody understands 4-way stops they are like witchcraft to most people
I do wish there were better designed roads and roadways and more people getting tickets for dangerous driving.
As far as carpool lanes I use them with my wife, but we live at the same location and only have the one car, so it just means a slightly slower fast lane with more assholes in SUVs.
pleasepaypreacher.net
This is horrifyingly true.
On more than one occasion I've explained who yields to who at a four way stop.
And on more than one occasion I've had the reply "But if they're on my right then I'm on their right so that doesn't work."
i was gonna be all "who yields to whom" but then i read the last line and it's the far greater outrage here
it huuuuuuuurts
O_o
4 way stops.Counterclockwise when congested, first come first serve otherwise.
How is this witchcraft?
Let's play Mario Kart or something...
America.
How the fuck does one not understand a 4-way stop?
people are really dumb, synd
like
really dumb
well the guy across from me is going straight so that means i get to go straight too!
And don't get me started on pedestrians. Know how I said we are a city of 233,000 people? Well another 50k students show up in the fall and leave in the spring, and while they are here every single one will just step out into traffic without looking because "state law says cars have to yield to pedestrians at all times!" No, bitch, they only have to yield when you enter in a safe and legal manner. I can't tell you how many I've nearly clipped because they decided to in front of me while wearing all dark, non-reflective clothing.
Which is funny (in that special US politics way) because better public transit is really good for business.
God damn do I hate this move so much. I also hate the "You didn't immediately start going when you got to the intersection its now my turn to go."
pleasepaypreacher.net
Do you live around the VCU campus in Richmond, VA, or are people just stupid and awful everywhere?
Rolling stops be best for traffic yo. Full stop only needed when congestion is high at the intersection.
UW-Madison. Students are stupid everywhere. Every-Fucking-Where
No they are stupid assholes everywhere. Like people in store parking lots who walk diagonally across the road as slow as fucking possible.
pleasepaypreacher.net
Or walk down the middle of the lane 2, 3, 4 or more abreast blocking everything.
And then they stop and talk
Walk talkers are bad, car talkers need to be drug out of their cars and executed in the streets.
pleasepaypreacher.net
The other day I almost got hit by a shitheel that thought red light was for plebes. While talking on the phone.
If thoughts could kill, it'd take a week to clean that car.
Wait...huh? So...four people stop at an intersection at all four sides. One set of two directly across from each other wants to go straight, while the other two want to go left and right. If everyone is signaling, why wouldn't the two straight crossers go, the right turn clear itself and then the left turn go? Or, hell, right turn, double straight, left turn? Why is it rude for the second guy going straight to double clear the intersection with the first guy? The right move is to wait for the guy turning left to go, then 2nd straight goes, then right turn dude?
Sorry, I should make a diagram...
And it's a bit off of topic on carpooling. Boo.
To go back to carpooling...I hate it when there is no carpool lane and the slow packed cars are over in the left lane, blocking faster traffic flow. Left is fast and pass, not cruise with traffic lane.