Even though the average gas price rose above four dollars last week—a week in which it typically declines from Memorial Day’s yearly highs—rising crude costs threaten to drive prices even higher by the end of the summer. Certain events like a hurricane or other natural disaster damaging refinery capacity, or a further instability in the Middle East, are also widely viewed as capable of single-handedly driving prices to five dollars a gallon at any time.

One of the most interesting aspects of this story though, is how price hikes have effected American driving habits. In May, we saw a dramatically slowed start to the summer driving season over Memorial Day weekend. SUV sales have also dropped to post-9/11 lows, with General Motors deciding recently to cut 700,000 light trucks and SUVs from its annual production plans.

Now comes an Ipsos survey that asked Americans directly how they were responding to pricey gas. As it turns out, 67 percent of us say we have already changed our driving habits in one way or another, and if gas hits five dollars, an additional 18 percent say they plan on doing so as well.

Most drivers are either cutting back on recreational driving (26%) or consolidating multiple errands into the same trip, with a minority opting for more significant changes like carpooling (7%), walking or biking (6%), using public transportation (4%), or buying a fuel efficient car (3%.) The longer gas prices stay this high, the more that is sure to change.