The House passed the bill in December, 169-22, but a number of Senate amendments require House approval before the legislation can reach Gov. Rendell's desk.

A "very pleased" Rep. Robert Freeman (D., Northampton), sponsor of the legislation, said he expected the House to approve the Senate changes when it reconvened the first week of June.

Given that House Bill 1281 has had "overwhelming support," Freeman said opposition from Rendell would be "unlikely" - especially since the environmental community favors it and the Pennsylvania Builders Association is taking a neutral stance.

Rendell spokesman Chuck Ardo said the governor would "need time to review" the Senate amendments.

"He sees the benefit of protecting the trail and providing a recreational and educational experience," Ardo said. "He certainly doesn't believe we should pave it and turn it into a go-cart track."

The legislation - an amendment to the Pennsylvania Appalachian Trail Act of 1978 - was spawned by outrage from environmental activists over the approval of development plans for a 4.2-mile road course for high-performance cars less than a half-mile from where the trail runs atop the scenic Blue Mountain range in Monroe County, north of Allentown.

The Blue Mountain Preservation Association and the Appalachian Trail Conference appealed to Monroe County Court, which found nothing in Eldred Township's land-use regulations or in the state's Trail Act to prohibit the $30 million Alpine Motorsports Club. Commonwealth Court upheld the decision.

The act had only urged trailside towns to pass ordinances to preserve its "natural, scenic, historic and aesthetic values." H.B. 1281 would require them to do so.

All area senators voted for the legislation.

Among the Senate amendments:

Local officials would have the ultimate discretion on how much land to zone. The law would not require an entire community be zoned.

Communities would have up to a year to adopt zoning.

Cooke Township, Cumberland County, population 117, would be exempt. Its portion of the trail is surrounded by state-owned forest and parkland and a private game preserve, Freeman said.

The Senate's action was applauded by PennEnvironment in Philadelphia, which has been lobbying for the bill.

"Clearly, this is an important part of our natural heritage that's worth protecting," director David Masur said.

When the Alpine complex was proposed and approved by Eldred officials - in 2002 - the township had no zoning. It does now, but too late to stop the rally course, which developers hope to open in summer 2009, pending state approval of stormwater-management permits.

Of the 55 communities along Pennsylvania's 229 miles of trail, nine have no zoning, according to PennEnvironment. The entire trail, a string of state and federal property, runs 2,175 miles through 14 states, from Georgia to Maine.