Eli5 How are carpool lanes supposed to help traffic? It seems like having another lane open to everyone would make things better?

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I live in Los Angeles, and we have some of the worst traffic in the country. I’ve seen that one reason for carpool lanes is to help traffic congestion, but I don’t understand since it seems traffic could be a lot better if we could all use every lane.

Why do we still use carpool lanes? Wouldn’t it drastically help our traffic to open all lanes?

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72 Answers

Anonymous 0 Comments

Citynerd made a video on HOV lanes literally this week: [https://youtu.be/3FYeebu0S4c](https://youtu.be/3FYeebu0S4c)

Re: your question – if the HOV lane leads to a pinch point, switching to a regular lane doesn’t help you reach the destination faster – at best, you get extra space for jammed cars, so the jam doesn’t spill back as far back/as quickly.

Anonymous 0 Comments

100 people drive to work, that means there are 100 cars on the road

100 people go to work, but they ride two to a car, there are 50 cars on the road

etc etc etc.

Anonymous 0 Comments

Some results from actual studies:

> A 2006 report found that METRO’s HOV lanes (consisting of 113 miles at the time) handled almost 118,000 person trips each weekday, by serving about 36,400 multi-occupant vehicle trips. The report found that the HOV lanes had lower average travel times than adjacent corridors and saved the average commuter 12–22 minutes per trip.
https://www.transportation.gov/mission/health/High-Occupancy-Vehicle-Lanes

> Evidence indicates that the carrying capacity on Onewa Road increased in both the
transit lane and the general traffic lane, while the transit lane patronage on buses
dramatically increased, as did the HOVs’ use of the lane. As such, the transit lane
carried 68 percent of all commuters in 27 percent of all vehicles on Onewa Road
(Murray, 2003).
https://www.nzta.govt.nz/assets/projects/ramp-signals/Priority-Lanes.pdf

[This paper](https://www.witpress.com/Secure/elibrary/papers/UT06/UT06019FU1.pdf) has an extended list of successes and problems. Enforcement has historically been one of the bigger problems, but technology is starting to solve that.

Anonymous 0 Comments

If a car has 5 seats, and 5 people are in it, that means there are less cars than if each had 1 person in it…

It’s not just for congestion though, it’s for the environment too

Anonymous 0 Comments

> It seems like having another lane open to everyone would make things better?

oh my sweet summer child.

also no they are trying to band aid the horrible traffic by getting several people into one vehicle. someone should really work on that! like the vehicle could have a designated driver, it would be big so many people fit and it would stop at alot of places so alot of different people could carpool together. Man i wish we had something like that :/

maybe it could even be on some kind of “rail” and it could have its completley own lane so it didnt even have to sit in traffic! man i wish we had something like that

Anonymous 0 Comments

YouTuber City Nerd recently made a video going into the upsides and downsides of HOV lanes.

Even creating one more lane magically from nothing would at best have a small, short term improvement, and in the long term would probably make traffic worse, not better.

Comparing a general lane to an HOV lane, that lane is probably carrying more people, and may be moving more cars when the general lanes get congested since it remains free flowing longer. Of course if that’s the case it may be making congestion worse elsewhere by letting more cars get there. In short, it’s complicated and depends a lot on context.

Regardless, both an HOV lane and a general purpose lane are vastly inferior use of space than a transit right of way that could move an order of magnitude more people and could put a serious dent in congestion by not only reducing car usage on that exact route, but around it as well.

Anonymous 0 Comments

> It seems like having another lane open to everyone would make things better?

oh my sweet summer child.

also no they are trying to band aid the horrible traffic by getting several people into one vehicle. someone should really work on that! like the vehicle could have a designated driver, it would be big so many people fit and it would stop at alot of places so alot of different people could carpool together. Man i wish we had something like that :/

maybe it could even be on some kind of “rail” and it could have its completley own lane so it didnt even have to sit in traffic! man i wish we had something like that

Anonymous 0 Comments

Citynerd made a video on HOV lanes literally this week: [https://youtu.be/3FYeebu0S4c](https://youtu.be/3FYeebu0S4c)

Re: your question – if the HOV lane leads to a pinch point, switching to a regular lane doesn’t help you reach the destination faster – at best, you get extra space for jammed cars, so the jam doesn’t spill back as far back/as quickly.

Anonymous 0 Comments

100 people drive to work, that means there are 100 cars on the road

100 people go to work, but they ride two to a car, there are 50 cars on the road

etc etc etc.

Anonymous 0 Comments

If a car has 5 seats, and 5 people are in it, that means there are less cars than if each had 1 person in it…

It’s not just for congestion though, it’s for the environment too