The rulebook does not say 1.5 steps. Maybe it did when we were kids and that's what we were taught. But it's not the modern rule. If anything, two steps off a drive is the modern rule. What is a 1/2 step anyway? I take one step and the other leg is moving and almost hits the ground? The NBA has a number of rules on traveling but this is the most pertinent: "A player who receives the ball while he is progressing or upon completion of a dribble, may use a two-count rhythm in coming to a stop, passing or shooting the ball."
The NCAA rules on traveling are pretty poorly written.
Section 72. Traveling
Art. 1. Traveling occurs when a player holding the ball moves a foot or both feet
in any direction in excess of prescribed limits described in this rule.
Art. 2. A player who catches the ball with both feet on the playing court may
pivot, using either foot. When one foot is lifted, the other is the pivot foot.
Art. 3. A player who catches the ball while moving or dribbling may stop and
establish a pivot foot as follows:
a. When both feet are off the playing court and the player lands:
1. Simultaneously on both feet, either may be the pivot foot;
2. On one foot followed by the other, the first foot to touch shall be the
pivot foot;
3. On one foot, the player may jump off that foot and simultaneously land
on both; neither foot can be the pivot foot.
b. When one foot is on the playing court:
1. That foot shall be the pivot foot when the other foot touches in a step;
2. The player may jump off that foot and simultaneously land on both;
neither foot can then be the pivot foot.
Art. 4. After coming to a stop and establishing the pivot foot:
a. The pivot foot may be lifted, but not returned to the playing court, before
the ball is released on a pass or try for goal;