Not a citation but most intersections are literal chokepoints for traffic. The throughput of those decide the speed of traffic. You can lookup "Cities in Motio

Not a citation but most intersections are literal chokepoints for traffic. The throughput of those decide the speed of traffic. You can lookup "Cities in Motion fix traffic" on Youtube if ypu want proof. So when you except that throughput is speed, you understand why every car comercial is shot at 3am traffic.