Interesting[0] story from a friend of mine who is a <i>real</i> engineer:<p>Back where he used to live at some point road authorities increased speed limits and found that average speed decreased. His explanation was simple: once speed limits matched drivers expectations they started to respect them. (Other explanations that I can pull from thin air now is police promising that the new limits will be enforced a lot less leniently than the old, or that speeds went down because of saturation congestion.)<p>[0]: although unconfirmed for me IIRC, maybe someone here can tell me were to find data
Very nice, I played a bit around with it but there is 1 thing that bothers me. The sliders all start at the left but the value it represents isn't at the left. Some sliders should start in the middle to be right.
I've seen many of these ring-road simulations over the years. They are great for pitching lower speed limits, but I fault their assumptions. Traffic does not feed on itself in this manner. Aberrant drivers and situations are constantly being inserted and removed from the system. A slowdown at point A does flow up/down to point B like a wave, but it doesn't wrap around back to point A to be amplified again.<p>I do credit this particular simulation for modeling acceleration/deceleration. Playing around with it leads to the conclusion that many congestion problems can be addressed by increasing the performance numbers for cars, and by encouraging people to use their brakes/engines to their full potential. We should all drive as if in nascar,
minimizing gaps to fully utilize the available road. Clarkson would be proud.<p>I would like to see a simulation of cars+trucks+motorcyles. Two-wheeled vehicles are common everywhere and in some countries are dominant on the roads, yet they are never included in these models. And toss in a few bicycles just for kicks.<p>Realworld "simulation":
<a href="https://www.youtube.com/watch?v=7wm-pZp_mi0" rel="nofollow">https://www.youtube.com/watch?v=7wm-pZp_mi0</a>
I love that it has really good model explanations.
On my simulations though, trucks tended to drive extensively on the left lane. In real life trucks don't usually do this.
This brings back some memories of traffic flow fundamentals.<p>I do remember an assignment that was modeling multiple different traffic flow models. The thing that stood out to me is how after a long time span with an network that was stuck with the same vehicles, like this model, traffic flow issues tended to become exaggerated.<p>As a traffic engineer, I use a product called Vissim to do exactly this kind of thing for real world scenarios. Very fun stuff.
It needs a slider for number of 80 year old grandpas who should have been off the road years ago but DMV keeps passing them to be nice.<p>Our town has implemented a few of these traffic circles. For some reason a memorial to the killed appears a few months each time after one is opened. I don't think it was drivers killed, I think it was pedestrians trying to cross at the inlets/outlets.
Interestingly, this confirms the common-sense wisdom that coasting, rather than braking, helps to even out traffic jams.<p>If you decrease the "comfortable deceleration" parameter all the way, you significantly increase the number of cars that can be handled without traffic jams.<p>Also, try turning T/s0/b all the way down, a all the way up, and then increase the density to about 75. Because the simulated drivers have very fast reaction times, the traffic oscillations propagate much faster than the cars are actually moving, creating some cool-looking spiral patterns.