Show HN: A Simple Highway Simulator • Hacker News Board

Re: Show HN: A Simple Highway Simulator

#41

Post by novaleaf » Tue, Oct 25, 2016, 1:06 PM UTC

mabcat wrote: post #37

cyberferret wrote: post #30

Interesting project! I had fun playing with it. I wanted to test the theory (which I saw in an article posted here on HN a few weeks ago) that a single car slowing right down on a busy highway (e.g. to avoid hitting an animal on the road or similar) can actually cause a traffic jam that goes back miles and can last for hours. I couldn't prove that hypothesis at this scale. I am assuming that the AI drivers have just…

The 200ms default reaction time in the simulation is wildly optimistic. I remember 1500ms from rider training and http://www.visualexpert.com/Resources/reactiontime.html seems to bear that out.

also braking: it looks like the cars can only brake as fast as they accelerate. seems like this should be a different slider.

Re: Show HN: A Simple Highway Simulator

#42

Post by tragomaskhalos » Tue, Oct 25, 2016, 2:28 PM UTC

scotty79 wrote: post #36

What I'm missing is right lane preference, that would control how much people obey the rule that you shouldn't be on the leftmost lane unless you are faster then the cars in the right lane in front of you and if you aren't much faster then the car that's next to you on the right lane you should slow down and place yourself after it or speed up and place yourself in front of it. It's horribly painful to watch two slow…

Or indeed left-lane preference, for British and Japanese users. But yes a more sophisticated simulation would use > 2 lanes, and have various controls for lane discipline, especially since poor lane discipline is a major contributor to congestion. This is a suggestion not a criticism btw, I had fun with this.

Re: Show HN: A Simple Highway Simulator

#43

Post by Silvanm » Tue, Oct 25, 2016, 8:58 PM UTC

Glad to see my first post on HN to receive such positive feedback. I guess I'll post my vacation projects regularly if they are appreciated :-)

If you want to see a more scientific approach at the subject I recommend looking at http://traffic-simulation.de/

Re: Show HN: A Simple Highway Simulator

#44

Post by QuarterReptile » Wed, Oct 26, 2016, 1:03 AM UTC

mjevans wrote: post #34

legohead wrote: post #25

Nice. I've wanted to do something like this, as I have a theory about the car pool lanes being worse for traffic. When traffic is bad, car pool lanes are just as backed up typically. When someone wants to get in the car pool lane upon entering the highway, they tend to do so fairly quickly. This can cause a shockwave as someone flies from one side of the highway to the other. The same thing can happen in the opposite…

In the uncounted thousands of hours of driving on the freeway in my life thus far, I've observed: * Drivers will improperly idle in a lane they feel safe in, refusing to keep right except to pass (this is actually state law where I live). * Any deviation from a straight, flat, roadway (corners, hills, dips, anything) will cause the flow to slow; even when you can proxy the status of the roadway in front by the tail-l…

On your first point, that's the norm in my driving (most of both US coasts.) I've sometimes wondered what the saturation level is where the left lane should just be another lane to increase steady state flow rate. I guess it's when the lane becomes too crowded to cycle properly.

On your second point, I've always just assumed that that was a tall car thing because I figured they probably get more uncomfortable cornering. The same way I probably seem irrational when I speed around pickup trucks: they probably fail to recognize that their driving in front of me is like putting a wall in my face (and unlike semi trucks the drivers are no better than the rest of the people on the road.)

On your third point, the US has baked in too many policies that are prohibitive to sensible development patterns. The implicit subsidies for low density living and the federally insured mortgage cone to mind as two of the worst.

Re: Show HN: A Simple Highway Simulator

#45

Post by hacker314159 » Wed, Oct 26, 2016, 1:54 AM UTC

Really cool project. I wonder if transportation agencies would want to use something like this for studying traffic.

Re: Show HN: A Simple Highway Simulator

#46

Post by netsharc » Wed, Oct 26, 2016, 8:11 AM UTC

jtolmar wrote: post #24

Here's something fun and counter-intuitive: From default settings, set speed variance to 50%, launch frequency to 120 cars/minute, and reaction time to 500ms. Unsurprisingly, this is chaos. Then, keeping those settings, clear the cars and set the target speed to 150km/h. The traffic mostly clears up! Since the cars are going faster, they leave the road sooner, meaning fewer are on the road at a time, fixing most prob…

This might depend on your screen size, on my screen the crashes occur on the right edge of the road.