The Knight Street Bridge is a crossing over the north arm of the Fraser River , the Canadian National Railway (CNR) line, and several roads, in Metro Vancouver .
31-453: The 1929 Vancouver Major Streets Plan designated the Clark-Knight corridor as a six-lane arterial road . The upgrade delayed for decades, Knight St. was never a streetcar route, and experienced less commercial and lower intensity development than nearby arterials. A late 1950s metropolitan highway planning committee recommendation included a proposed 1970s crossing in the vicinity, to relieve
62-657: A crash cushion , crash attenuator , or cowboy cushion , is a device intended to reduce the damage to structures, vehicles, and motorists resulting from a motor vehicle collision . Impact attenuators are designed to absorb the colliding vehicle's kinetic energy . They may also be designed to redirect the vehicle away from the hazard or away from roadway machinery and workers. Impact attenuators are usually placed in front of fixed structures near highways , such as gore points , crash barrier introductions, or overpass supports. Temporary versions may be used for road construction projects. Impact attenuators are designed to absorb
93-442: A black lid. The "Fitch Highway Barrier System" was invented by race car driver John Fitch after the 1955 24 Hours of Le Mans race when his co-driver, Pierre Levegh rear-ended Austin-Healey driver Lance Macklin at high speed, launching his car through the air and into the spectator's area. The car burst into flames and took the lives of Pierre and 84 spectators in one of the worst accidents in racing history . He stated he
124-399: A crash, while others require minimal repairs. Truck mounted attenuators (TMA), similar in some ways to railcar buffers , can be deployed on vehicles that are prone to being struck from behind, such as snow plows and road construction or maintenance vehicles. Work zone regulations often specify a minimum buffer distance between the attenuator truck and the work area, and a minimum mass for
155-1101: Is a high-capacity urban road that sits below freeways / motorways on the road hierarchy in terms of traffic flow and speed . The primary function of an arterial road is to deliver traffic from collector roads to freeways or expressways , and between urban centres at the highest level of service possible. Therefore, many arteries are limited-access roads , or feature restrictions on private access. Because of their relatively high accessibility , many major roads face large amounts of land use and urban development, making them significant urban places. In traffic engineering hierarchy, an arterial road delivers traffic between collector roads and freeways . For new arterial roads, intersections are often reduced to increase traffic flow . In California, arterial roads are usually spaced every half mile, and have intersecting collector(s) and streets. The Traffic Engineering Handbook describes "Arterials" as being either principal or minor. Both classes serve to carry longer-distance flows between important centers of activity. Arterials are laid out as
186-518: Is dissipated by scattering the sand, and the vehicle decelerates smoothly instead of violently striking a solid obstruction, reducing the risk of injury to the occupants. Fitch barriers are widely popular due to their effectiveness, low cost, and ease of setup and repair or replacement. Since first being used in the late 1960s, it is estimated that they have saved as many as 17,000 lives and approximately $ 400 million per year in property damage and medical expenses. Non-gating impact attenuators arrest
217-594: The Oak Street Bridge . Constructed 1969–1974, the structure was the second cast-in-place segmental cantilever bridge built in North America, the first being Quebec in 1964. For many years, the 109.7-metre (360 ft) main span held the world record for this design. Each drop-in span, which joins the two separate parallel cantilever spans from the main piers, is an arched post-tensioned concrete girder, resting on rubber bearings at each end. Like Knight Street ,
248-502: The City of Richmond to install a second water main to Mitchell Island in 2002. In 2011, the bridge underwent a seismic retrofit of three abutments, which were vulnerable to settlement or collapse from movements during soil liquefaction . The subsurface conditions comprise dense till-like soils for the north bridge, but potentially liquefiable deltaic sediments for the south bridge. The north abutments and piers rest upon spread footings, whereas
279-485: The backbone of a traffic network and should be designed to afford the highest level of service , as is practical, as per the aforementioned "Traffic Engineering Handbook". The construction and development of arterial roads is achieved through two methods. By far the most common is the upgrading of an existing right-of-way during subdivision development. When existing structures prohibit the widening of an existing road however, bypasses are often constructed. Because of
310-714: The bridge underwent extensive rehabilitation that required overnight single lane closures in each direction. The work included lighting upgrades, pier repairs, and the replacement of crash cushions , signage, and bearing and expansion joints. Rehabilitation works also took place in 2023, including bearing replacements, milling and repaving the top layer of concrete deck with polyester polymer concrete (PPC) overlay to prevent future corrosion, pier patch repair expansion joint replacement and railing replacement ( https://www.translink.ca/plans-and-projects/projects/maintenance-and-upgrade-program/bridge-projects ). Formerly, transport planning had not been coordinated with land use planning. However,
341-643: The bridge was named after Robert Knight, a property owner in South Vancouver in the late 19th and early 20th centuries. During the planning stage, the project was known as the Fraser Street Bridge Replacement . At the official opening ceremony in January 1974, Graham Lea , provincial Minister of Highways, cut the ribbon. On hand were Gil Blair, mayor of Richmond, and Art Phillips , mayor of Vancouver. Totalling about $ 15M, including $ 3M for roadways,
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#1732843985044372-441: The bridge was the scene of more than 2,500 car accidents during 2013–2017, of which nearly half resulted in injuries or fatalities. The Marine Dr. on and off ramps have rated among Canada's most dangerous intersections. In 2017, the city made design and signalling changes to enhance safety, which included a new turn bay for westbound vehicles on SE Marine Dr. turning north, and a new shared walking and cycling path. During early 2020,
403-486: The busier junctions. Speed limits are typically between 30 and 50 mph (50 and 80 km/h), depending on the density of use of the surrounding development. In school zones, speeds may be further reduced; likewise, in sparsely developed or rural areas, speeds may be increased. In western Canada, where freeways are scarce compared to the rest of North America, flashing early-warning amber lights are sometimes placed ahead of traffic lights on heavy signalized arterial roads so
434-514: The colliding vehicle's kinetic energy to bring it to a stop safely. If no impact attenuator is present, a vehicle which strikes a rigid roadside object will suddenly stop. A person inside will promptly collide with the interior of the vehicle, and that person's internal organs will collide with their chest wall, causing severe internal injuries and possibly death. By safely dissipating the vehicle's kinetic energy, impact attenuators help prevent such injuries. Impact attenuators can be categorized by
465-401: The deceleration (negative acceleration) applied to the vehicle occupants. A smaller amount of energy is consumed in the work of crumpling the plastic containers. In cold climates, water-filled attenuators are either avoided, or have additives such as magnesium chloride salt added to them to prevent freezing. A Fitch barrier consists of sand-filled plastic barrels, usually yellow-colored with
496-605: The establishment of the Agricultural Land Reserve in 1973 encouraged the development of the Surrey plateau, and reduced encroachment upon the agricultural lowland of Richmond. If land use had been determined by market forces alone, development along the Knight St. extension south of the bridge would have created the largest industrial park in region. The initial zoning proposal was for a broader footprint south to Cambie Rd., but
527-473: The final version provided the present narrower corridor south to Westminster Hwy. In 2014, improvements to the Mitchell Island interchange included extended loading bays to aid bus manoeuvering, widening passenger walkways, installing over 60 metres (197 ft) of safety barriers, new traffic islands, and new signage. Arterial road An arterial road or arterial thoroughfare
558-423: The ground, and therefore benefit from easy deployment and relocation using barrier transfer machines and cranes. They are non-redirective, meaning they do not deflect vehicles that impact the side back into the roadway. The energy of the impacting vehicle accelerates the water in the barrels vertically and laterally consuming that energy in work done on the water. Additionally, this work is done over time which reduces
589-503: The method used to dissipate kinetic energy: Gating impact attenuators allow vehicles impacting from the side to pass through them (akin to a gate). Gating attenuators are more economical, but require a greater clear space surrounding them to be effective; without enough space, errant cars may pass through into another hazard, such as into lanes of opposing traffic. Water-filled attenuators consist of containers filled with water to absorb impact energy. They are typically not anchored to
620-426: The motion of vehicles that impact head-on, whilst deflecting vehicles that impact the side of the barrier. They are anchored and more expensive, but can be used in tighter spaces. Crash cushions are constructed of multiple segments, which crumple into each other when collided with to absorb the impact. Their main benefit is in their reusability; some attenuators can automatically return to their original position after
651-514: The occupants of the impacting vehicles. This is because TMA vehicles are designed to absorb the energy of the impact, while firetrucks are too rigid and can cause severe injuries or death. In the United States , impact attenuators are tested and classified according to AASHTO Manual for Assessing Safety Hardware (MASH), first issued in 2016 to supersede National Cooperative Highway Research Program (NCHRP) Report 350: Recommended Procedures for
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#1732843985044682-413: The off and on ramps for the island. The electrically heated deck minimizes winter de-icing. On the underside of the deck, the western spans carry a maintenance walkway, above which are a water pipe, gas pipe, and electrical lines. The navigational clearance is 19–23 metres (62–75 ft) at the apex, depending upon the tide. Upgrading Knight St., and eliminating the load weight restrictions associated with
713-453: The placement and general continuity of arterial road corridors , sewers, water mains, conduits and other infrastructure are placed beneath or beside the roadbed. In North America, signalized at-grade intersections are used to connect arterials to collector roads and other local roads (except where the intersecting road is a minor side street, in which case a stop sign is used instead). In Europe, large roundabouts are more commonly seen at
744-533: The previous structure, this Vancouver – Richmond link eased congestion, and connected to Highway 99 , and since 1989, Highway 91 . Averaging over 100,000 vehicle crossings daily, the bridge is the second busiest in the Lower Mainland. Cyclists are legally required to ride on the sidewalks. On January 15, 2000 the boom of a mobile crane transported on a barge named T.L. Sharpe , towed by the Sea Cap XII , struck
775-402: The province funded the scheme. On formation in 1999, TransLink assumed ownership and maintenance responsibilities. The configuration comprises an overpass of Marine Drive, the 238-metre (781 ft) Knight Street Bridge North, and the 1,198-metre (3,930 ft) Knight Street Bridge South. The six-lane medium-level bridge reduces to four lanes over Mitchell Island , the outside lanes becoming
806-398: The rate of deceleration. Fitch barriers are often found in a triangular arrangement at the end of a guard rail between a highway and an exit lane (the area known as the gore ), along the most probable line of impact. The barriers in front contain the least sand, with each successive barrel containing more, so that when a vehicle collides with the barrels they shatter, the kinetic energy
837-460: The south ones rest upon timber and steel-pipe piles. To densify the ground, 105 injection boreholes were drilled to a depth of 12.3 metres (40 ft) around one abutment, and filled at pressure with a low mobility grout up to the surface. Timber compaction piles were used for densification in other areas. Steel-pipe piles were installed at a pier adjacent to the riverbank. Ranking first in Vancouver,
868-1043: The speed limits can be raised to speeds of over 80 km/h. These warning lights are commonly found on high-speed arterial roads in British Columbia. The width of arterial roads can range from four lanes to ten or even more; either as a dual carriageway or sharing a common center lane, such as a contraflow lane or as a central turning lane. As with other roadway environmental consequences derive from arterial roadways, including air pollution generation, noise pollution and surface runoff of water pollutants. Air pollution generation from arterials can be rather concentrated, since traffic volumes can be relatively high, and traffic operating speeds are often low to moderate. Sound levels can also be considerable due to moderately high traffic volumes characteristic of arterials, and also due to considerable braking and acceleration that often occur on arterials that are heavily signalized. Impact attenuator An impact attenuator , also known as
899-845: The truck, to minimize the chances that the truck will be pushed forward by a crash into the workers or machinery. This is especially important in mobile work zones where the truck's parking brake may not be engaged. The truck may also be in movement (albeit slower than the vehicles that could crash into it). In some countries, such as Sweden, road safety authorities operate dedicated TMA vehicles registered as emergency vehicles, able to be dispatched to blockages or emergencies. TMA vehicles are better suited for protecting emergency or construction workers on roadways than non-specialized vehicles, such as firetrucks. TMA vehicles have several benefits over firetrucks, such as lower purchase and repair cost, improved firefighting capacity (because firetrucks are available for use and won't be damaged), and enhanced safety for
930-484: The underside of the Knight Street Bridge at 1:45 PM, damaging the bridge and the fixtures secured underneath its deck. The impact caused the boom to bend and the crane to slide off the barge and sink, and the bridge was closed to traffic for about 48 hours. Water supply to Mitchell Island via the bridge was shut down for 25 days, and an emergency bypass water supply from Vancouver was installed. The incident prompted
961-399: Was inspired by sand-filled fuel cans which he used to protect his tent from strafing during World War II . Early prototypes were self funded and tested due to low initial support. As a proof of concept Fitch used liquor barrels filled with sand to create the necessary impact attenuation, then personally crashed reinforced vehicles into them while recording with a high speed camera to capture