Motorists choose main streets primarily based on reducing travel time.
Stop lights on arterials are timed based on cars and trucks traveling at or above speed limits that are generally 60-70kmh. On a bike this timing is unfeasible except during strong tailwinds, and I rarely realize any time savings on major arterials. In fact I often just end up rolling from red light to red light.
And this is not factoring in traffic back-ups, which tend to be the worst on major roads. The litmus test for this is that side streets in my area are overflowing with through-traffic taking short cuts to reduce travel time, despite the turn restrictions, traffic calming, and stop signs attempting to minimize this.
Another factor that puts most motorists on main roads that these streets most often offer freeway access, another useless attribute for non-motorized road users.
Last edited by ghettocruiser; 11-05-07 at 02:38 PM.