While, in the right environment, a single driver may be able to break a jam, a single driver can create one just about anywhere.
Can a single car break a traffic jam?
71–80 of 108 posts
Re: Can a single car break a traffic jam?
#72No, at least not for I-405 / I-5 near Seattle. These roads, due to a complete lack of effective urban planning and development, are several times over capacity. I like to think that this heuristic would be effective for such cases. * Aim for a hard speed limit (maybe the actual speed limit). * Actually obey the law of this state: Keep Right Except to Pass. * ALWAYS allow merges (from either side) with higher priority…
> Aim for a hard speed limit (maybe the actual speed limit).
That's not gonna work. Depends on the day, the time, the weather, rain, fog etc. Some days, traffic flows at 70 on 405 during rush hour. If you go the legal speed limit you will be the dangerous blockage that makes everyone else down, and makes a few people unnecessarily grumpy. Other days it's misty because the water on the road gets stirred up by all the trucks. It's impossible to go the speed limit on these days, the flow is going 45.
There is no hard rule, except: go with the flow. SEE the traffic. BE the traffic. Do not FIGHT the traffic.
Re: Can a single car break a traffic jam?
#73No, at least not for I-405 / I-5 near Seattle. These roads, due to a complete lack of effective urban planning and development, are several times over capacity. I like to think that this heuristic would be effective for such cases. * Aim for a hard speed limit (maybe the actual speed limit). * Actually obey the law of this state: Keep Right Except to Pass. * ALWAYS allow merges (from either side) with higher priority…
> Aim for a hard speed limit (maybe the actual speed limit). That's not gonna work. Depends on the day, the time, the weather, rain, fog etc. Some days, traffic flows at 70 on 405 during rush hour. If you go the legal speed limit you will be the dangerous blockage that makes everyone else down, and makes a few people unnecessarily grumpy. Other days it's misty because the water on the road gets stirred up by all the…
Enforcing a speed limit on freeways is completely possible. They've got it done in England. What you need to do is capture license plates on entrance and exit, and calculate the average speed for each car's trip. If the speed limit is 50 MPH for traffic-flow reasons, and you do your 15 mile commute in 15 minutes, you're getting a "60 in a 50 MPH zone" ticket in the mail, every single time.
People will learn in a hurry that speeding is pretty much pointless and self-harming.
Re: Can a single car break a traffic jam?
#74Earlier quoted context omitted.
Tariffs. If people want access to a congested zone, charge them for it. Dynamically adjust the tariff based on the level of congestion. Of course people hate this and wail that it isn't fair, but it is among the more fair solutions to the immediate problem and inflicting traffic jams is probably not a good way to address economic inequality.
Agree. Tolls (assuming they means the same thing as tariffs) can also create the critical mass necessary for commuter bus lines to work, thereby allowing people to spend only a little more than they do now on commuting but get there faster since the roads are cleared. (The per person effective toll would be lower on a bus, even if they are charged by size.) But they would have to be much higher than in most proposals…
Tolls could even be done after the fact. Imagine a special tax on self-driving cars and trucks: 0.0x cents per mile if driven between 9AM and 5PM, based on mileage logs and all miles assumed to be driven then. If a corporation wants the discount, it can produce GPS logs showing its vehicles were logging all that mileage during off-peak hours.
Re: Can a single car break a traffic jam?
#75Earlier quoted context omitted.
I think you need to read the update #2 in the page you linked, of course you can't create capacity out of nowhere, but if you are in a "phantom jam" situation it does help to "smooth things out" as the page clarifies (which I think is what this article is about)
I guess I am just not used to that sort of traffic jam where I am. Here, it is always just 'way too many fucking cars on the road'
In that traffic jam, is 1 car passing that point every 2s? No? Then I guess your road is not operating at peak capacity.
Re: Can a single car break a traffic jam?
#76Traffic jams exist because humans drive cars, and humans are not designed to process data at 120 kilometers per hour. This is a major repost but still misses the main problem. When you look at a car in front of you, you perceive it as a stationary wall, not a moving wall. When you slow down, you're trying to avoid hitting where the car in front of you is when you press on the brake pedal. You're not smart enough to r…
But my car weighs only 1600kg, and for years my passengers have been telling me I'm going to hit the car directly in front of me. Looks like that day has already come ;)
Re: Can a single car break a traffic jam?
#77Earlier quoted context omitted.
> Aim for a hard speed limit (maybe the actual speed limit). That's not gonna work. Depends on the day, the time, the weather, rain, fog etc. Some days, traffic flows at 70 on 405 during rush hour. If you go the legal speed limit you will be the dangerous blockage that makes everyone else down, and makes a few people unnecessarily grumpy. Other days it's misty because the water on the road gets stirred up by all the…
Enforcing a speed limit on freeways is completely possible. They've got it done in England. What you need to do is capture license plates on entrance and exit, and calculate the average speed for each car's trip. If the speed limit is 50 MPH for traffic-flow reasons, and you do your 15 mile commute in 15 minutes, you're getting a "60 in a 50 MPH zone" ticket in the mail, every single time. People will learn in a hurr…
They've really got the surveillance state thing down to a science there, if they're doing things like that. In North America, where there are cameras, they tend to only look at your speed at a specific moment.
Re: Can a single car break a traffic jam?
#78Earlier quoted context omitted.
I guess I am just not used to that sort of traffic jam where I am. Here, it is always just 'way too many fucking cars on the road'
In that traffic jam, is 1 car passing that point every 2s? No? Then I guess your road is not operating at peak capacity.
That is the maximum number of cars that can pass a given point in 2 seconds; it does not mean that a road operating at peak capacity can reach that number.
You also have to take into account cars merging onto the road you are on. Imagine a road acting at peak efficiency, with a car passing every 2 seconds. Now merge in more cars. They are going to push back every car behind by that same 2 seconds.
You can read the section on 'merging' in the link above to read more details.
Re: Can a single car break a traffic jam?
#79Earlier quoted context omitted.
Truckers (professional drivers) do this all the time. If ever there is a traffic jam on the highway, you will see the big rigs consistently leaving hundreds of feet of space in front of them. They also seem to concentrate in the center lanes of the highway for reasons I haven't figured out yet.
In a traffic jam, wouldn't the alternative to leaving plenty of space be constantly starting and stopping? That seems pretty like a lot of work for the driver in a big rig.
ding ding ding ding! We have a winner. The just leave it in the fastest gear that is slow enough to not hit the car in front of them. For the extra 5min it costs it's a lot easier than pushing a bazillion pound clutch twice per cycle.
Re: Can a single car break a traffic jam?
#80Earlier quoted context omitted.
In a traffic jam, wouldn't the alternative to leaving plenty of space be constantly starting and stopping? That seems pretty like a lot of work for the driver in a big rig.
ding ding ding ding! We have a winner. The just leave it in the fastest gear that is slow enough to not hit the car in front of them. For the extra 5min it costs it's a lot easier than pushing a bazillion pound clutch twice per cycle.
Yep! I've only ever driven manual transmission cars, and my dad taught me that early on. "Just leave it in first and idle along." Even in a very driver-friendly manual car, stop and go traffic can be brutal.