Zion National Park's plan to limit motor vehicle traffic in the park's narrow canyons could have been implemented this spring, but funding was not available, spokesman Robert Andrew said Saturday.

"The need for a public transportation system to alleviate vehicle congestion has been recognized since the early 1980s," said Andrew.But the need became more and more urgent as the number of tourists visiting the park increased by 7 percent a year to a record 2.17 million visitors during 1988.

Officials came up with a proposal to limit the number of vehicles in the scenic park, use a mass transit system to move visitors to major attractions, and bar mobile homes and trailers from the road that dead ends at the Temple of Sinawava.

"We were ready to begin in April of this year," said Andrew. "But the costs were greater than we realized. Now we're looking at the spring of 1990, if we can get the financing."

Zion officials still are trying to determine whether the park should run the proposed mass transit system or let a concessionaire handle the job.

"It would be something like a city bus system, running about every 15 minutes," he said. "We don't want a tour bus where a guide explains the sites. If we had that type of system, people getting off one bus to see one of the sites might not be able to get on a following bus."

"The process is now under way" to ban long-term parking from April 1 through Oct. 1, during the height of the tourist season, Andrew said.

"A maximum length of stay of two hours would be implemented at all parking areas between Zion Lodge and the Temple of Sinawava. The idea is to prevent hikers who plan to spend most of the day or longer in the park from taking up scarce parking spaces."

Vehicles entering the canyon above Zion Lodge would be restricted to those under 21 feet in length and 5,000 pounds gross weight, once the plan is implemented in 1990 or later. And all day-use visitors would be required to park towed vehicles before entering the canyon.

"Basically, we're talking no mobile homes, boats or trailers," Andrew said.

And the park plans to restrict vehicles going through the narrow, two-lane Zion Tunnel, requiring a ranger escort through the tunnel for vehicles wider than 8 feet and longer than 30 feet.

"It's a serious safety issue now that we're experiencing serious crowding. People may not like the wait for escorted vehicles, but safety is our most important concern," he said.

The proposed plan follows a five-day transportation survey conducted last August. More than 90 percent of the visitors surveyed said Zion needed some type of public transportation system.

People wishing to comment on the interim proposal have until March 17 to submit their suggestions to park officials, Andrew said.