Traffic restrictions, increased shuttle service and expanded parking are among a range of possible strategies Glacier National Park officials will consider as they develop a long-term corridor plan for Going-to-the-Sun Road, according to a list of preliminary alternatives released Friday.

Glacier in 2013 began the process of creating a corridor plan for the heavily trafficked 50-mile road that is the only east-west route across the park.

The plan is intended to address road and parking congestion, resource impacts and future changes in visitation — particularly as a warming climate is expected to expand the tourist season for the park.

Informed by public comments, university-led surveys and expert contractors, officials developed four separate strategies, along with a “no action” alternative.

With the release of the preliminary alternatives, the park is accepting public comments to be considered as it develops the draft corridor plan. That will require an environmental impact statement and a preferred alternative.

The park is accepting public comments until June 5 and the draft plan is expected to be released this fall.

One of the possible options would build additional parking and infrastructure to accommodate increased visitation, along with continuing the park’s shuttle system, which was put in place when Sun Road rehabilitation began in 2007.

Another alternative would restrict the number of vehicles in the park and expand the shuttle system to handle more visitors. Under that option, time limits would be imposed on vehicles and reservations would be required during the peak season.

It also would prohibit overnight parking, require day-hike permits on some trails during the peak season and increase biking opportunities, such as developing biking trails and holding “bike only” days on Sun Road. In anticipation of increased use, trails would be widened and hardened, and additional trails and handrails could also be added.

A third option would scrap the shuttle system entirely and rely on vehicle restrictions to manage congestion. Biking opportunities would be expanded.

The park’s final option is called “adaptive response to alternative futures.”

It provides park officials with the greatest flexibility to respond to changing conditions in the park, establishing “triggers” and resultant management actions.

It keeps on the table all of the management options in the other alternatives and requires park officials to develop plans based on different future scenarios. The least restrictive actions would go into effect first, followed by more heavy-handed responses such as overnight parking prohibitions, hiking permits and conversion of one loop of Avalanche Campground and the west-side baseball field into parking lots.

All the possible options include growing partnerships with gateway communities. The final alternative also suggests pointing more visitors to those communities to reduce park congestion.

The Going-to-the-Sun Road corridor area includes all trails and pullouts that can be reached from the park’s main road. This area experiences a high concentration of visitor use, particularly from the end of June to mid-August. The corridor also contains a high level of biological diversity and numerous cultural resources.

The planning process was begun to address the stress on park resources caused by increased visitation to the world-renowned park.

Visitation to the park set a record in 2014 at 2.3 million. Use of some of the park’s most popular hiking trails has exploded in the last few decades, with some experiencing a 250 percent increase compared with 1988.

To view the newsletter containing the preliminary alternatives or to submit comments, go to parkplanning.nps.gov/documentsList.cfm?projectID=47660.

Reporter Samuel Wilson can be reached at 758-4407 or by email swilson@dailyinterlake.com