A voluminous supplemental environmental impact statement outlining alternatives for improving Provo Canyon to meet projected traffic levels for the next 20 years has been made available for public perusal.

People concerned about future highway development in Provo Canyon have until mid-August to study the document and its proposals. Public hearings, scheduled for Aug. 17 in Heber and Aug. 18 in Provo, will give people an opportunity to tell state officials how they feel about proposed changes for a 30-mile stretch of U.S. 189 from the mouth of Provo Canyon to U.S. 40 south of Heber.Public comments will be incorporated in the final impact statement, after which the state Transportation Commission and Federal Highway Administration will recommend one of four alternatives that will govern canyon highway improvements. The study is available at the Orem and Provo public libraries, the Harold B. Lee Library at Brigham Young University and the Wasatch County Library in Heber City.

The alternatives were developed by the consulting firm of Howard, Needles, Tammen and Bergendorf in conjunction with UDOT and the Federal Highway Administration. The consulting firm developed the alternatives over the past year as part of the supplemental environmental impact statement.

The statement reassesses issues examined in a 1978 environmental study and addresses deficiencies that sparked a federal court lawsuit against UDOT. The lawsuit prompted a federal judge to allow only limited construction to proceed in the canyon in conjunction with preparation of the updated environmental impact statement.

The study says traffic accidents along the highway stretch claimed 24 lives from 1979-86, and that the highway's accident rate is much higher than that of similar state highways.

"Ever-increasing traffic volumes on this facility, designed 60 years ago, have led to accident rates which are up to 80 percent above those experienced on similar highways in Utah," the report says. "The purpose of this project is to provide appropriate improvements which will eliminate existing hazardous driving locations and provide a facility which has the capacity to safely accommodate the projected traffic for the next 20 years."

The Provo Canyon Citizens Participation Committee, appointed by the consulting firm, has recommended a multiuse alternative, which would be a four-lane divided highway designed to accommodate traffic traveling 50 mph and would depart somewhat from the highway's existing alignment. This alternative would be a compromise that addresses local access and arterial-roadway functions and could include the construction of two short tunnels.

Utah County commissioners and actor Robert Redford also support the $88 million multiuse alternative.

Jim Naegle, UDOT engineer for location and environmental studies, said, "UDOT has no preferred alternative at this point. We try not to be biased. What we try to do is balance out what we're able to give to the driving public with a minimum amount of effect on the environment. The study should give us all the information we need to make these decisions."

The other development alternatives under consideration are:

-No-build, which would maintain the highway as is. The current level of roadway repair and maintenance would continue, and safety improvements would be limited to signing and striping. Construction projects under way in the canyon would be completed with accompanying landscaping. Cost would be $13.4 million.

-Accessibility, which would concentrate on addressing the road-access needs of those living in the canyon. A minimum two-lane highway would be maintained and designed to accommodate traffic speeds of 40 mph. This alternative would cost $32 million and would closely follow the existing highway alignment.

-Mobility, which would give precedence to traffic passing through the canyon. At a cost of $101 million, this alternative would be a four-lane divided highway designed for speeds up to 60 mph. This alternative would have the greatest impact on vegetation and wildlife, including loss of 131 acres of deer and elk winter range.