Ackerman Steering. According to the CarBible.com, Charles Darwin's father, Erasmus Darwin, wrote a paper in 1758 describing this steering arrangement but didn't patent it. Ackermann re-invented it in 1817. Erasmus was a doctor and made house calls in wooden wagons over rough roads in England. Apparently there was some interest in his geometry but it didn't catch on. As traction improved over time, scrubbing became less tolerable.

When a vehicle with more than two wheels makes a turn, all the wheels should be turning around concentric circles otherwise something has to skid or "scrub" as they call it. The drawing on the right is clearly not correct.

   More Correct-er drawing at left. Each wheel travels on a circle with different radius but the same center.

Wikipedia explaination good.

   Camber: Negative Camber, shown at right, improves tire grip when cornering. Now days vehicles generally have a small amount of negative camber (-.5°). Negative camber improves the grip when cornering. This site says cars used to have positive camber to offset for vehicle loading.
Tilting the wheel causes it to want to turn (like a motorcycle or bicycle) and so if one wheel hits a bump and looses traction, the other wheel will make the car turn a little, possibly causing jittery steering. This sounds similar to Toe In but I could find nothing that says that for sure.

   The best thing for a low speed pedal powered heavy vehicle probably is to preserve the undersized and underengineered bearings as much as possible, which woul mean no camber only a little castor.
Wikipedia

   Caster wheels are alsways steering wheels. There is a steering axis and the wheel axle.There are two ways to make a wheel caster. One is to have the axle behind the axis. The other is to tilt the steering axis. Both means cause the contact point of the tire to the ground to fall behind the steering axis. The drag from this contact straightens the wheel.
   A tilted axis has the added effect of changing the camber when the wheel is turned. Fortunately the change is in the beneficial direction. While greater caster angles serve to improve straight-line stability, they also cause an increase in steering effort. Three to five degrees of positive caster is the typical range of settings, with lower angles being used on heavier vehicles to keep the steering effort reasonable.
Wikipedia

   Kingpin Inclination or KPI is seen from the front of the car. When the wheel turns, the car is actually lifted. So the weight of the car straightens the wheel.
   KPI also effects the camber induced by caster. Web sites that say the negative camber is lessened are confusing. Is a negative number lessened when it's absolute value increases? Yes. But is that what they meant? I don't know. I hope you feel as lessoned as I.
   When the kingpin points to a spot directly under the wheel or "the center of the contact patch," then the car has centerpoint steering. This makes low speed steering easy. Bugatti in the 30's achieved this with positive camber of 3.5 deg (a lot) and vertical kingpins (zero KPI). There are several forums discussing this geometry.
When the king pin points inside the contact patch as shown at right, the driver feels the road more. The difference is the Scrub Angle."
Wikipedia