This roughly matches my estimate of evil drivers on the road, people cutting lines violently and not using turning lights, pushing to insert on the right when they used the emergency lane to pass everybody in a slowdown...
On the highway segments, most cars were just trundling along between 2 and 20 mph over the limit, generally keeping reasonably to themselves. When an obstacle appeared on the roadside (stopped motorist, police, other), people flexed to let other cars get left and then returned to normal driving.
Sure, I noticed a few people driving aggressively, following too closely, changing lanes excessively to squeak out one or two extra spots, but that was perhaps 50 cars at the very most in 1600 miles of driving. 1 or 2 per hour, not 1 per 20.