The Portage Glacier Highway, or Portage Glacier Road, is a highway located in the U.S. state of Alaska. The highway is made up of a series of roads, bridges, and tunnels that connect the Portage Glacier area of the Chugach National Forest and the city of Whittier to the Seward Highway. Most of the highway travels through mainly rural areas just north of the Kenai Peninsula, with the Anton Anderson Memorial Tunnel passing under Maynard Mountain, part of the Chugach Mountain Range. Parts of the route were first constructed in the early 1900s, and the entire highway was completed on June 7, 2000, as part of the Whittier Access Project. The main portion of the highway traveling from the western terminus to the Begich, Boggs Visitor Center at Portage Lake is designated as National Forest Highway 35 by the United States Forest Service (USFS).
Route description The portion of the Portage Glacier Highway traveling from the Seward Highway to the Begich, Boggs Visitor Center is designated as part of Forest Highway 35, a Federal Forest Highway (FFH). Forest Highways are funded and administered by the USFS and the Federal Highway Administration; the system was created by the Federal Aid Highway Act of 1921. FFH-35 is one of the 33 Forest Highways that are currently designated in Alaska.
Chugach National Forest The Portage Glacier Highway begins at an at-grade intersection with the Seward Highway in the former town of Portage. At this point, the highway is a two-lane, asphalt road. Almost immediately after the Seward Highway intersection, the road crosses over the Coastal Classic line of the Alaska Railroad. The highway continues in a southeasterly direction along the Portage Valley, with Portage Creek to the north and pine forests to the south. After about , the roadway intersects a small gravel road that leads to the Moose Flats Day Use area, which has access to several scenic hiking trails. Peaks of the Chugach Mountains, along with several hanging glaciers, can be seen from the road; Portage Glacier is out of view. The highway passes through a low-lying wetland before reentering forest and providing access to the Alder Pond Day Use area and the Portage Valley RV park.
Portage Glacier Highway continues southeastward, providing access to the Black Bear Campgrounds, maintained by the USFS. The roadway bends eastward, passing the USFS Williwaw Campgrounds, as well as several small gravel roads. The road continues for a short distance before passing the Begich, Boggs Visitor Center and associated buildings, comprising the headquarters of Portage Glacier unit of the Chugach National Forest. The highway continues onto the Portage Creek Bridge, which is long. It allows the highway to cross over the small Portage Creek, which drains Portage Lake, in turn fed by Portage Glacier. The bridge ends at the start of the Portage Lake Tunnel. The tunnel is long and constructed of concrete. The route proceeds to a portion of road known as the "Rock Cut at Portage Lake" by the Alaska Department of Transportation & Public Facilities (DOT&PF). This road passes along the coast of Portage Lake and borders a large, man-made cliff to the north (hence the name "Rock Cut"). This portion of the route terminates at the Placer Creek Bridge. The bridge, which is just long, spans Placer Creek, the smaller of the two creeks feeding Portage Lake. The highway continues to the six-lane Bear Valley Staging area and the toll booth for the Anton Anderson Memorial Tunnel. The road continues into the Anton Anderson Memorial Tunnel.
Anton Anderson Memorial Tunnel
The Anton Anderson Memorial Tunnel, often called the Whittier Tunnel after the town at its eastern terminus, is a dual-use (bimodal) highway and railroad tunnel that passes under Maynard Mountain. The tunnel is at . At a length of , or 2.51 miles, it is the longest highway tunnel and longest combined rail and highway tunnel in North America. The tunnel originated as a rail-only tunnel, excavated in 1941–1942. The tunnel was upgraded to bimodal use by the Kiewit Construction Company between September 1998 and mid-summer 2000. In 1976 it was renamed in memory of Anton Anderson (1892–1960), chief engineer of the Alaska Railroad and under whose supervision the tunnel had been built.
The redesigned tunnel is fitted with a combined single uni-directional highway lane and single-track railway. The floor of the tunnel is constructed of 1,800 texturized concrete panels, each , with the railroad tracks sunken slightly below the road surface. The interior is exposed rock, and contains several "safe-houses", which are small buildings that are used in case of severe earthquakes, vehicle fires, or other emergencies. The tunnel also contains several pull-outs, which are reserved for disabled vehicles. As motor vehicle speed in the tunnel is limited to 25 miles per hour (40 km/h), it takes about ten minutes to travel from end to end. The tunnel uses a combination of portal fans and reversible jet fans to ensure proper air flow and air quality throughout the tunnel. There are two backup generators to ensure that the computerized traffic controls and safe-house ventilation systems in the tunnel continue to function in the event of a power failure.
The tunnel can accommodate either eastbound traffic, westbound traffic, or the Alaska Railroad but only one at any given time. Because rail and road traffic must share the tunnel, it is coordinated by two computer-based systems — the Tunnel Control System and the Train Signal System. These systems control the timing of vehicles entering the tunnel, spacing them for safety, and lower railroad gates when a train is approaching. The tunnel's entrance portals are designed in an A-shape, with a large, train-sized "garage door", which allows traffic in and out of the tunnel. The entrance portals are designed to withstand the force of an avalanche. The tunnel's eastern terminus is in Whittier. The staging areas on either end of the tunnel can accommodate as many as 450 vehicles waiting to pass through.
Vehicle convoys enter the tunnel in alternating directions every half hour. Scheduled and unscheduled trains can cause delays of up to 30 minutes. The tunnel operates from early morning until late evening on a schedule that varies seasonally and according to construction and maintenance needs. Larger or heavier vehicles have to be carried as rail transport. Pedestrians and bicycles are prohibited.Alaska Administrative Code, Title 17. Transportation and Public Facilities, Chapter 17.38. Anton Anderson Memorial Tunnel. Section 17.38.035. Prohibitions.
Track circuits in the tunnel had problems because of moisture; in 2015 these were replaced with axle counters.[Railway Gazette International September 2015 pg55
Whittier After exiting the tunnel, the highway enters the nine-lane Whittier staging area, where it passes several of the tunnel's automated control systems. Before traveling past the single-runway Whittier Airport, the route intersects two small roads, one of which is the Portage Pass Trail access route. Running parallel to the Alaska Railroad line, the route - now named West Camp Road - continues between the Passage Canal and several mountains for approximately . Passing by the Cliffside Marina and the Alaska Railroad Whittier Depot, the route crosses over Whittier Creek before immediately making a left onto Whittier Street, crossing the railroad and bending southeastward and traveling past a large parking lot, the headquarters. Traveling past several businesses making up central Whittier as well as the city park, used for Whittier Parking and Camping, the highway turns east and intersects Glacier Avenue, as well as a short pedestrian pathway. The roadway continues through central Whittier before reaching a four-way intersection with Blackstone Road, Eastern Avenue, and Depot Road, after which the route transfers to the latter. The road continues along Passage Canal for a short distance, while traveling towards the Alaska Marine Highway (AMHS) pier. Depot Road splits away from the highway, which continues for a short distance along Dock Access Road before reaching its eastern terminus, the AMHS pier.
Traffic The highway is maintained by the Alaska Department of Transportation & Public Facilities (AkDOT&PF). Part of the job of the AkDOT&PF is to measure traffic along the highway. These counts are taken using a metric called annual average daily traffic (AADT). This is a statistical calculation of the average daily number of vehicles that travel along a portion of the highway. The estimated AADT for the Portage Glacier Highway is 1,030 vehicles. In addition to taking AADT, the AkDOT&PF also takes monthly and yearly counts for the highway. The road's yearly traffic count for 2010 was 234,738 vehicles. The roadway's highest monthly traffic is in mid-summer, when an average of nearly 50,000 vehicles use the tunnel each month. The highway's lowest monthly traffic is in late winter, when the average monthly traffic is only about 6,000. The monthly and yearly counts are taken at the entrance to the Anton Anderson Memorial Tunnel. The entire length of the highway is designated as an Intermodal Connector Route, part of the National Highway System (NHS), a network of roads important to the country's economy, defense, and mobility.
Scenic and recreational opportunities
The Portage Glacier Highway offers numerous scenic and recreational opportunities, mostly located along the section designated as FFH-35. A short, long boardwalk trail and the long Trail of Blue Ice are accessible through the Moose Flats Day-Use area. A viewing area for the Explorer Glacier is located near milepost 2, and a turnout for the Portage River is located near milepost 3. Near milepost 4 is the Williwaw fish viewing observation deck, which allows travelers to view spawning salmon in July through September. The long loop Williwaw Nature Trail is accessible through the Williwaw Campground. The trail provides views of the Middle Glacier. At the turnout for the Begich, Boggs Visitor Center is the Byron Glacier Trail as well as several others. The Portage Glacier can be seen on a short cruise on the M/V Ptarmigan; the glacier is no longer visible from the road. Past milepost 6 is a turnout for the Byron Glacier and Portage Lake.
Moose can be seen along the highway, as well as black and brown bears. Bald eagles can occasionally be seen from the highway. During spring and autumn, migrating species of ducks, geese, swans, and cranes can be seen throughout the region. Spawning salmon species of sockeye, chum, and coho can be seen in Portage Creek. Several unique species of wildflowers are found along several of the trails in the area. Whittier annually holds the Walk to Whittier, which is an event where pedestrians walk through the Anton Anderson Memorial Tunnel to Whittier, the only time pedestrians may use the tunnel. The event has been held since 2002, except it was not held in 2010. The walk traditionally takes place in June.
Tolls A toll is charged for access through the Anton Anderson Tunnel. The fees are collected from vehicles traveling eastbound. The fee for a regular vehicle is $13, as is the price for motorcycles. Vehicles pulling trailers must pay a higher toll, set at $22. Small buses and regular RVs are charged $38, while large buses must pay $137. Oversize and unusually sized vehicles, those wide and high must pay $330 per use. Vehicles that are exempt from paying tolls are those owned by the Alaska Railroad, the DOT&PF, or any emergency or law enforcement vehicle. Any vehicles owned or operated by any state government agency or school district pay $11.