At Dagget, the big, blue car with a lady driver sounded the warning signal and passed Mack Nolan and the Cadillac roadster.

Like Casey Ryan, Nolan is rather proud of his driving, and with sufficient reason.
He was already hurrying, not to overhaul Casey, but to arrive soon after him.
Women drivers loved to pass other cars with a sudden spurt of speed, he had found by experience.

They were not, however, consistently fast drivers.

Mack Nolan was conscious of a slight irritation when the twin-six took the lead.

Somewhere ahead--probably in one of the rough, sandy stretches--he would either have to pass that car or lag behind.
Your expert driver likes a clear road ahead.
So Mack Nolan drove a bit harder, and succeeded in getting most of the dust kicked up by the big, blue car.