Matt Yglesias links to an IBM survey asking people how much they'd be willing to pay to shave 15 minutes off their daily commute, and concludes that most people would consider $10 a pretty good deal. James Joyner, who commutes 45 minutes to work each day, is skeptical. "I simply don’t believe the numbers," he says.
I commute about 30 seconds each day, so I don't really have a personal opinion about this. But here's a data point. A few years ago a toll road company opened up a highway that slashed the commute time coming in to Irvine from Riverside County. A few of my coworkers who lived up there were ecstatic: it would cut their travel time by upwards of 45 minutes each way, they said.
Now, they might have been exaggerating. Maybe it was more like 30 minutes. But the price of the toll road at rush hour is only about $4, and since the toll folks could charge more if they wanted to, this is presumably the fee that maximizes their revenue. If it really saves 30 minutes compared to taking the nearest freeway, it values commute time at roughly $8 per hour.
This is just one data point, and I don't know for sure how good a substitute the new toll road is for the existing freeways in the area. It's not a bad one, though. And surely there are plenty of other examples like this, where a toll road roughly parallels a free road, which gives you a good idea of how much people are willing to pay in real life to avoid crawling in traffic. That seems like a much better way of collecting this data than taking a survey.