According to state law, ATVs and other recreational vehicles must be registered with the Pennsylvania Department of Conservation and Natural Resources.

As of last month, 152,201 ATVs were registered as active, meaning the owners have paid the $20 two-year fee to ride legally on designated public trails and roads or to ride by permission on private land.

Limited registrations, which cost nothing but are limited to use on an owner's land, number 71,563.

Of the state's 67 counties, Butler County ranks seventh in ATV registrations.

At 6,861 active registrations, Allegheny County ranks highest, followed by Westmoreland County at 6,447, Luzerne at 5,274, Lancaster at 4,954, York at 4,268, Erie at 4,626 and Butler at 4,177.

"There are very few (counties) in the 3,400 and above registrations, so that shows you do have a major interest there," said Terry Brady, deputy press secretary for the DCNR.

With the increase in the popularity of ATV riding in Pennsylvania comes an increase in accidents, Brady said.

In 2004, 26 fatalities involving ATVs were reported, compared to 42 the following year.

The 255 accidents involving ATVs in 2004 jumped to 397 the following year.

"Almost everything has almost doubled, and we know that registration hasn't doubled," Brady said.

Despite the increase, Brady said most of the accidents occur on public highways, which prohibit recreational vehicles except on some designated township roads. Fewer than 10 of the reported accidents last year occurred on trails, he said.

For more information on ATVs, log on to www.dcnr.state.pa.us and click the Forestry link.