Last week's Bike Week here in Bozeman got a lot of people out of their four-wheeled gas burners and onto their pollution-free two-wheelers. And that's a good thing for a lot of reasons. It cuts down on our increasingly irritating traffic; it gives us some exercise and it's just plain exhilarating.

But Bike Week also drew attention to a bit of a paradox. While most of today's Baby Boomer parents profess to prefer a more active, simple, less-fossil-fuel-dependent lifestyle, they apparently don't promote the same in their children. A Chronicle report on Bike Week activities cited a recent National Household Travel Survey finding that, while 48 percent of children walked or biked to school in 1969, only 13 percent did so in 2009.

A follow-up, nonscientific poll of Chronicle editorial page readers over the weekend came up with more encouraging numbers. Some 68 percent of respondents said they believe it to be safe for Bozeman kids to walk or ride a bike to school, while 32 percent did not. But do they practice what they preach?

A casual observation of Bozeman elementary and middle schools at the end of the school day reveals that many students ride school buses or are picked up by parents. Even those who walk or bike to school are often accompanied by a parent.

Whatever most of today's parents say - that they feel their children would be safe walking or biking to school - they are apparently reluctant to put those beliefs into practice. They seem to be plagued with a nagging anxiety about what could happen if they let their children out of their sight in the streets.

But in fact the world is a safer place now - by far - than it was when the boomers themselves were children. The rate of fatal accidents - the leading cause of death in children - has decreased by 50 percent since 1980. And, while the highly publicized cases of Elizabeth Smart and Jaycee Dugard have fostered a morbid fascination and dread of kidnapping, actual abductions by a stranger are very rare.

Biking and walking aren't just good things for the parents. They're good for the kids, too. They need the exercise and independence that comes with it. Now we just need to get past our irrational fears and let them do it.