Algodoo

They actually were done at the same time

I agree with the adding of traffic lights, but you need to imagine the costs to place all of these, wire them(such roads often stretch over kilometers), and then get a CPU to control them. You also need to remember that the roads that are "red" quickly fill up over dozens of dozens of meters, and once they finally go green(something a normal person in a car does not want to wait for), the reaction time of all these person will cause the line to slowly acellerate to maximum(once the first person starts driving, the last person notices this about 5 minutes later). This causes the other lines for ones to wait even longer again, resulting in them filling once again. One of the usual problems in traffic jams is the transmission of the signal that you can drive. For every driver, about 1 second has to pass in order for the next one to start driving. multiply this by the length of the road divided by the average car size, and you get quite some delay. Then add the time needet for the last member of the line to reach the end of the jam, and you get an even larger number. And if you have to multiply that time by the amount of merging roads, you get a time that no normal person likes to wait if he is heading home from a tiring day of work and just wants to relax...

A major factor that affects fuel economy and the overall efficiency of the traffic flow is the WAY people drive. As an example, I happen to be a fairly aggressive driver (do not equate "aggressive" with "reckless"). I have always believed that if most people drove the way that I do, there would be fewer crashes, and the traffic flow, overall, would be much more efficient. So, how can you get most people to drive like I do? EDUCATE them! As part of getting your driver's license, you would have the option of taking a course titled "Effective Driving Techniques". The course would go beyond just getting your license, and it would teach people how to move most efficiently through various traffic conditions, and how to maximize your fuel economy while minimizing your trip time. If people drove sensibly (which they do not now) I believe that traffic lights would become redundant, and could possibly be removed completely from all roads. I realize that this is just a dream of mine, and can probably never happen, but I believe that it could be very possible to implement.

FRA32,
I agree with what you say, but I am unwilling at this point to modify the code to model the more accurate driver behavior that you describe.

Xray,
I will leave a space for you when I see you merging from the on ramp. I'm not sure if aggressive driving results in a higher car mesh rate (in cars per minute), but if it does, then we are in agreement. Maybe everybody should drive bumper cars (or electronic bumper cars that don't actually crash).

Intresting scene.
I was wondering, what would be better a roundabout or crossroads?

The MythBusters put this to the test and they determined that a roundabout was better than crossroads.