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39-716: Leith Saddle is a saddle between the sources of the Water of Leith and the Waitati River , approximately halfway between Dunedin 's northern suburb of Pine Hill and the outlying settlement of Waitati . The saddle is a strategic point where the Dunedin Northern Motorway , part of State Highway 1 traverses a fragile alpine forest. Proposed road works to straighten a dangerous corner here conflict with conservation values. Water supply pipelines, and popular tramping and cycling routes also converge at

78-504: A mining background, expressed a common superstition that a woman brought bad luck to a mine. One worker insisted, "It's a jinx. I've seen too many die after a woman was in the tunnel." Bonnema sued the department for the right to work inside the tunnel. She countered she was in better shape and more agile than most of the men who were working on the tunnel. Emboldened by the passage of an equal rights law in Colorado, she finally entered

117-619: A 1.64% grade , with an elevation of 11,013 feet (3,357 m) at the east portal and 11,158 feet (3,401 m) at the west portal. At its dedication, the Eisenhower Tunnel was the highest vehicular tunnel in the world. While it remains the highest vehicular tunnel in the US, and longest mountain tunnel and highest point on the Interstate Highway System, higher tunnels have since been constructed elsewhere, such as

156-426: A long term intention in 2004 to realign SH1 in the vicinity of Leith Saddle; construction would require removal of some old-growth forest . The forest here features a species of Libocedrus , variously called Pahautea, Kaikawaka or New Zealand cedar, Libocedrus bidwillii , which is unusual in this region of New Zealand. Transit New Zealand stated in 2004 that Leith Saddle has 250% more accidents than average for

195-531: A nearby mountainside, as with the Eisenhower Tunnel bypassing Loveland Pass in the Rockies, to allow faster traffic flow throughout the year. The top of a pass is frequently the only flat ground in the area, and may be a high vantage point. In some cases this makes it a preferred site for buildings. If a national border follows the ridge of a mountain range, a pass over the mountains is typically on

234-549: A round of negotiations with Utah officials, it was decided the best option was to follow the US Route 6 corridor. Engineers recommended tunneling under the pass, rather than attempt to build a route across conforming to Interstate Highway standards . The Eisenhower–Johnson Memorial Tunnel was known as the Straight Creek Tunnel during construction, named for the waterway that runs along the western approach to

273-786: A style of street racing which may take place on these roads. There are thousands of named passes around the world, some of which are well-known, such as the Khyber Pass close to the present-day Afghanistan-Pakistan border on the ancient Silk Road , the Great St. Bernard Pass at 2,473 metres (8,114 ft) in the Alps , the Chang La at 5,360 metres (17,590 ft), the Khardung La at 5,359 metres (17,582 ft) in Ladakh , India and

312-464: Is also named. The eastbound bore was completed in 1979 and is named for Edwin C. Johnson , a Colorado governor and U.S. Senator who lobbied for an Interstate Highway to be built across Colorado. The Eisenhower Memorial Bore (westbound tunnel) is 1.693 miles (2.72 km) long, while the Edwin C. Johnson Memorial Bore (eastbound tunnel) is 1.697 miles (2.73 km) long. The tunnels are sloped with

351-888: Is also used, particularly in Europe. In the highest mountain range in the world, the Himalayas, passes are denoted by the suffix "La" in Tibetan, Ladhakhi, and several other regional languages. Examples are the Taglang La at 5,328 m (17,480 ft) on the Leh-Manali highway , and the Sia La at 5,589 m (18,337 ft) in the Eastern Karakoram range. Scotland has the Gaelic term bealach (anglicised "balloch"), while Wales has

390-420: Is defined as a mountain pass. Passes are often found just above the source of a river , constituting a drainage divide . A pass may be very short, consisting of steep slopes to the top of the pass, or a valley many kilometers long, whose highest point might only be identifiable by surveying . Roads and railways have long been built through passes. Some high and rugged passes may have tunnels bored underneath

429-771: Is the Brenner pass in the Alps . Some mountain passes above the tree line have problems with snow drift in the winter. This might be alleviated by building the road a few meters above the ground, which will make snow blow off the road. There are many words for pass in the English-speaking world. In the United States, pass is very common in the West , the word gap is common in the southern Appalachians , notch in parts of New England , and saddle in northern Idaho . The term col , derived from Old French,

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468-399: Is transmitted northwards from Dunedin's municipal water system via a new pipeline to the rural settlements of Waitati , Warrington and Seacliff . 45°48′00″S 170°30′58″E  /  45.800094°S 170.516081°E  / -45.800094; 170.516081 Mountain pass Mountain passes make use of a gap , saddle , col or notch . A topographic saddle is analogous to

507-674: The Continental Divide in the Rocky Mountains . With a maximum elevation of 11,158 feet (3,401 m) above sea level , it is one of the highest vehicular tunnels in the world. The tunnel is the longest mountain tunnel and highest point on the Interstate Highway System . Opened in 1973, the westbound bore is named after Dwight D. Eisenhower , the U.S. President for whom the Interstate system

546-530: The Fenghuoshan Tunnel , a rail tunnel in China. The tunnel bores measure 48 ft × 40 ft (15 m × 12 m). The traveled portion is a rectangular shape just over 16 ft (4.9 m) tall. The space above this is used for forced air ventilation while the space below the roadway is used for drainage. As of March 2023 , more than 434 million vehicles had passed through

585-602: The New Zealand state highway network and that the accident rate increased by 50% in the ten years to 2004. They said realignment here would reduce traffic delays, fuel use, crashes, and emissions of carbon dioxide and carbon monoxide . A contour pipeline running southbound over the saddle from several tributaries of the Waitati River feeds two of Dunedin's water supply reservoirs in Leith Valley : Ross Creek Reservoir and Sullivans Dam. Treated, fluoridated water

624-594: The Palakkad Gap at 140 metres (460 ft) in Palakkad , Kerala , India . The roads at Mana Pass at 5,610 metres (18,410 ft) and Marsimik La at 5,582 metres (18,314 ft), on and near the China–India border respectively, appear to be world's two highest motorable passes. Khunjerab Pass between Pakistan and China at 4,693 metres (15,397 ft) is also a high-altitude motorable mountain pass. One of

663-528: The Eisenhower bore was $ 42 million, but the actual cost was $ 108 million (equivalent to $ 741 million in 2024). Approximately 90% of the funds were paid by the federal government, with the state of Colorado paying the rest. At the time, it set a record for the most expensive federally aided project. The excavation cost for the Johnson bore was $ 102.8 million (equivalent to $ 432 million in 2024). Not included in

702-442: The biggest setbacks was the discovery of fault lines in the path of the tunnel that were not discovered during the pilot bores. The first construction contractor went bankrupt excavating rock in this fault zone. These faults began to slip during construction and emergency measures had to be taken to protect the tunnels and workers from cave-ins and collapses. Despite the best efforts of engineers, three workers were killed boring

741-458: The border, and there may be a border control or customs station, and possibly a military post. For instance, Argentina and Chile share the world's third-longest international border , 5,300 kilometres (3,300 mi) long, which runs north–south along the Andes mountains and includes 42 mountain passes. On a road over a pass, it is customary to have a small roadside sign giving the name of

780-432: The clearance could be raised even a few inches. The 2007 retrofit also added a weigh-in-motion system that calculates a safe speed for trucks on the 7% grades and curves on the departures from the tunnels and displays it to each driver. While the tunnel has largely supplanted the older route of U.S. Highway 6 over Loveland Pass , hazardous material carriers (hazmats), bicycles, and pedestrians are prohibited from

819-559: The east portal. A Martin 4-0-4 charter aircraft, one of two carrying the college football team of Wichita State University , crashed just north of the highway ( 39°41′37″N 105°52′57″W  /  39.6935°N 105.8825°W  / 39.6935; -105.8825 ). Of the 40 passengers and crew on board, only nine survived. The team was on its way to a game with Utah State University in Logan and had recently refueled at Denver's Stapleton International Airport . The plane carrying

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858-581: The famous but non-motorable mountain passes is Thorong La at 5,416 metres (17,769 ft) in Annapurna Conservation Area , Nepal. Eisenhower Tunnel The Eisenhower Tunnel , officially the Eisenhower–Edwin C. Johnson Memorial Tunnel , is a dual-bore, four-lane vehicular tunnel in the western United States , approximately 60 miles (97 km) west of Denver , Colorado. The tunnel carries Interstate 70 (I-70) under

897-627: The figures is about $ 50 million in non-boring expenses during the construction of both tunnels. Upon opening, it became the highest-elevation tunnel in the world, taking the title from the Salang Tunnel in Afghanistan. The tunnel's construction highlighted issues relevant to the feminist movement. When Janet Bonnema applied for a position as an engineering technician with the Colorado Department of Transportation she

936-409: The first tube and four in boring the second. Further complicating construction, the boring machines could not work as fast as expected at such high elevations and so the productivity was significantly less than planned. The frustration prompted one engineer to comment, "We were going by the book, but the damned mountain couldn't read." Though the project was supposed to take three years, the tunnel

975-410: The mathematical concept of a saddle surface , with a saddle point marking the minimum high point between two valleys and the lowest point along a ridge. On a topographic map , passes can be identified by contour lines with an hourglass shape, which indicates a low spot between two higher points. In the high mountains, a difference of 2,000 meters (6,600 ft) between the summit and the mountain

1014-479: The pass and its elevation above mean sea level . Apart from offering relatively easy travel between valleys, passes also provide a route between two mountain tops with a minimum of descent. As a result, it is common for tracks to meet at a pass; this often makes them convenient routes even when travelling between a summit and the valley floor. Passes traditionally were places for trade routes, communications, cultural exchange, military expeditions etc. A typical example

1053-410: The retrofit, about 20,000 vehicles per year tripped the alarm. The trucking industry argued that many of these trucks were under the height requirement but tripped the alarm due to their air suspensions (which can be lowered during their journey through the tunnel) or due to snow and ice atop the trailer. During this time, the trucking industry estimated the number of alarms would drop by as much as 80% if

1092-773: The saddle. The Water of Leith 's source is 100 metres to the south of Leith Saddle, at a height of 380 metres above sea level. The Leith Saddle Track is a 3.5 hour climb through native cloud forest to Swampy Spur and Swampy Summit with links to other walkways in the Silverpeaks and Dunedin's hills. The Dunedin Northern Motorway has an at-grade intersection at the Leith Saddle summit with Leith Valley Road and Waitati Valley Road. Both have low motor vehicle volumes and have metalled surfaces, making them attractive to cyclists. Transit New Zealand signalled

1131-696: The similar bwlch (both being insular Celtic languages). In the Lake District of north-west England, the term hause is often used, although the term pass is also common—one distinction is that a pass can refer to a route, as well as the highest part thereof, while a hause is simply that highest part, often flattened somewhat into a high-level plateau. In Japan they are known as tōge , which means "pass" in Japanese. The word can also refer to narrow, winding roads that can be found in and around mountains and geographically similar areas, or specifically to

1170-628: The team's starters departed Denver and traveled a poorly planned scenic route. The other plane, carrying reserve players, followed the original route and landed safely in Logan. While the Eisenhower Tunnel was primarily intended as a transportation tunnel, it also serves as a water tunnel for water diversion from the western side of the Continental Divide to the eastern side. Water from the Straight Creek watershed (a tributary of

1209-469: The tunnel and must use the pass, which is longer, steeper, and 834 ft (254 m) higher at 11,992 ft (3,655 m). And while the tunnel's route is less formidable than the pass, its approaches are steep nonetheless and have runaway truck ramps . If Loveland Pass is closed—such as for construction or storms—the hazmat prohibition is temporarily lifted and the tunnel is closed to regular traffic once per hour to allow hazmats to be escorted through

Leith Saddle - Misplaced Pages Continue

1248-399: The tunnel in a convoy . The idea for a tunnel under Loveland Pass existed since at least the 1950s. William A.H. Loveland had an idea of a tunnel under the divide in 1867, but instead got the wagon road now known as Loveland Pass built. Serious discussion began when the state of Colorado lobbied for the Interstate Highway System to route a transcontinental highway across Colorado. After

1287-407: The tunnel, with an entourage of reporters, on November 9, 1972. Some workers walked off the job, and at least one of them yelled, "Get those women out of here." She remained determined and re-entered the tunnel a few days later. The next time, she dressed in coveralls and was even assigned tasks on the roof of the tunnel overlooking the men below. Surprised that nobody had apparently noticed that she

1326-404: The tunnel. Before the tunnel was dedicated, it was renamed to honor Dwight D. Eisenhower and Edwin C. Johnson. The original Pioneer bore to access the two larger bores was "holed through" in late 1964, after fourteen months. Construction on the first bore of the tunnel was started on March 15, 1968. Construction efforts suffered many setbacks and the project went well over time and budget. One of

1365-409: The tunnel. This figure includes a significant number of visitors to Colorado's ski resorts . Due to additional height restrictions from variable-message signs and lighting systems, the original posted clearance of the tunnels was 13 ft 6 in (4.11 m). The trucking industry lobbied the Colorado Department of Transportation (CDOT) to increase the vertical clearance. In 2007, the tunnel

1404-470: Was a woman, she stated, "I had a good disguise." Bonnema continued to dress in coveralls during her subsequent work in the tunnel so as not to attract attention. In November 2023, CDOT opened an updated operations center and new garage bays at the tunnels. On Friday, October 2, 1970, during the tunnel's construction, workers constructing the tunnel were among the first on scene of a plane crash that had occurred less than two miles (3.2 km) northeast of

1443-559: Was given an assignment on the Straight Creek Tunnels project. Her supervisor misread her resume and thought that he was hiring "James." When the supervisor discovered that the department had hired a woman, she was tasked with doing support work from the office. There was opposition to a woman entering the construction site. One supervisor stated that if she entered, "Those workers would flat walk out of that there tunnel and they'd never come back." The workers, most of whom had

1482-488: Was not opened to traffic until a March 8, 1973, dedication ceremony by Governor John Love . Initially, the northern Eisenhower bore was used for two-way traffic, with one lane for each direction. The amount of traffic through the tunnel exceeded predictions, and efforts soon began to expedite construction on the southern bore. Construction began on the eastbound Edwin C. Johnson tunnel on August 18, 1975, and finished on December 21, 1979. The initial engineering cost estimate for

1521-450: Was retrofitted with lower-profile lighting and signs, increasing its clearance by 5 in (13 cm) to 13 ft 11 in (4.24 m). A height detector near each tunnel entrance sounds a siren and turns traffic signals red, stopping all traffic, if an overheight vehicle attempts to enter the tunnel. The entrance will remain closed until the vehicle is removed from the freeway, which can cause severe delays. CDOT noted that prior to

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