>>15067112 (lb)

My guess is that he didn't want so much damage early that the car would be undriveable and he would be at the mercy of the parade onlookers.

So, he waited until there was a good chance to hit as many as he could and still escape. Don't aim for the sidewalk (curb), and don't hit anyone at high speed. Minimize car damage.

There were about 12 side streets leading off the parade route if he wanted to get off the route without hitting anyone.

5 million bail tells me it was all intentional.