So here we have traffic engineers admitting that motorists won't follow the law, and yet their entire warrant system is built on the premise that motorists will follow the law. This is exactly why we have a built road environment that is failing us miserably. Well, that and our near-total lack of law enforcement.

And before anyone jumps on this in attack mode, honestly answer these questions:
1. Do you stay below the speed limit at all times, including the basic speed law (which has some amazingly explicit provisions, like 15 mph on narrow residential streets-those with travel lanes of 9 feet or less)?
2. Do you come to a full and complete stop fully behind the limit line at each and every stop sign and red light?

For a time when I lived in a city the size of Springfield, almost all people answered those questions affirmatively because there was zero-tolerance traffic law enforcement. There were also no fatal traffic crashes (and very few collisions at all).