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38-539: The road starts at its junction with Outram Road , Eu Tong Sen Street and New Bridge Road in the north and ends at its junction with Keppel Road in the south. It is intersected by the arterial Neil Road . Namesake roads include Cantonment Link , a one-way road which connects Keppel Road to Cantonment Road, and Cantonment Close . The Police Cantonment Complex and The Pinnacle@Duxton , an award-winning 50-storey residential development in Singapore's city center,

76-400: A SPUI takes up considerably less space than a full cloverleaf interchange , allowing construction to take place on a limited amount of property and minimizing state use of eminent domain . Finally, SPUIs are reportedly safer than other space-efficient interchange forms, such as (standard) diamond interchanges. Research suggests that, although there may not be a significant difference between

114-557: A SPUI will allow traffic to proceed straight through from the offramp to the onramp; this usually happens when the ramps connect with frontage roads . Since most through traffic travels over or under the intersection, the SPUI is still much more efficient than a surface intersection. The most commonly cited advantages of SPUIs are improved operation efficiency and safety as well as reduced right-of-way requirements compared to other interchange forms. Left-turning traffic from both directions of

152-536: A continuous green T-intersection with the bridges. The ramps cross each other at-grade , with a traffic light -controlled intersection. An interchange, like that in Millvale, Pennsylvania, formerly existed at the junction of SR 7 and SR 822 at the now-demolished Fort Steuben Bridge in Steubenville, Ohio . The northbound carriageway of SR 7 passed under the bridge, with lefthand ramps meeting

190-458: A longer bridge of the free-flowing road to cross the wider area required for the SPUI intersection below. Because vehicles must be able to cross the pavement in six different ways, a SPUI generally has a very large area of uncontrolled pavement in the middle of the intersection. This can be unsafe particularly if drivers are unfamiliar with the interchange type. Drivers making a left turn may become confused as oncoming turning traffic passes them on

228-462: A problem in cases where the arterial, or nonfreeway road, already requires a very wide bridge. The intersection of 97 Street , having seven throughlanes, with Yellowhead Trail in Edmonton , Alberta, Canada, though a diamond interchange in concept, required such a wide bridge that traffic-signal phasing allows this intersection to behave as a SPUI. A freeway-over SPUI (as in the lower photo) requires

266-410: A right turn (across oncoming traffic) in one turn). It also allows for diagonal crossings ( pedestrian scramble ) and reduces crossing distances for pedestrians. Intersections generally must manage pedestrian as well as vehicle traffic. Pedestrian aids include crosswalks , pedestrian-directed traffic signals ("walk light") and over/ underpasses . Walk lights may be accompanied by audio signals to aid

304-565: A right turn on red, and sometimes left on red depending on the geometry of the intersection in question, possible in many cases, often without stopping. Cyclists ideally have a protected bike lane on the approach to the intersection, separated by a concrete median with splay kerbs if possible, and have a protected bike lane width of at least 2 metres if possible (one way). In the Netherlands , most one way cycle paths are at least 2.5 metres wide. Bicycle traffic can be accommodated with

342-415: A setback crossing of the pedestrians and cyclists , generally between 1.5–7 metres of setback, a forward stop bar, which allows cyclists to stop for a traffic light well ahead of motor traffic who must stop behind the crosswalk. Separate signal staging or at least an advance green for cyclists and pedestrians is used to give cyclists and pedestrians no conflicts or a head start over traffic. The design makes

380-913: Is a four-way interchange on the German autobahn network. Autobahndreieck (literally "autobahn triangle"), short form dreieck , and abbreviated as AD, is a three-way interchange on the German autobahn network. At intersections , roads cross at-grade . They also can be further subdivided into those with and without signal controls. Signalized designs include advanced stop line , bowtie , box junction , continuous-flow intersection , continuous Green-T, double-wide, hook turn , jughandle , median u-turn, Michigan left , paired, quadrant , seagulls , slip lane , split, staggered , superstreet , Texas T , Texas U-turn and turnarounds . Non-signalized designs include unsignalized variations on continuous-flow 3 and 4-leg, median u-turn and superstreet, along with Maryland T/J, roundabout and traffic circle . In

418-439: Is a type of highway interchange . The design was created in order to help move large volumes of traffic through limited amounts of space efficiently. A SPUI is similar in form to a diamond interchange but has the advantage of allowing opposing left turns to proceed simultaneously by compressing the two intersections of a diamond into one single intersection over or under the free-flowing road. The term "single-point" refers to

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456-844: Is also a SPUI on the Frankenschnellweg , the urban part of the A73 , and Maximilianstraße, in Nuremberg (at 49°27′06″N 11°02′17″E  /  49.451708°N 11.038102°E  / 49.451708; 11.038102 ). Smaller versions of the SPUI can also be found on non-autobahn roads in German cities, with right-turning traffic under signal control, located in Heilbronn , Karlsruhe , Sindelfingen , Stuttgart , and Wiesbaden . SPUIs are also found in Australia, Canada, Hong Kong, Indonesia, and Singapore. A rarely built variant of

494-531: Is an example of such a location. In the United Kingdom and other countries, the practice of giving names to junctions emerged, to help travellers find their way. Junctions took the name of a prominent nearby business or a point of interest. As of the road networks increased in density and traffic flows followed suit, managing the flow of traffic across the junction became of increasing importance, to minimize delays and improve safety. The first innovation

532-453: Is located along the road. One of the interesting landmark along Cantonment Road is the Lim's Ancestral Temple, known as Lim See Tai Chong Soo Kiu Leong Tong (林氏大宗祠九龙堂家). The ancestral temple was founded in 1928, the main purpose of this ancestral temple is to conduct the ancestral worship of the Lim's ancestors and Mazu (天后圣姑), whom they regarded as their Grand-Auntie. One of the temple's founder

570-413: Is the wealthy Nan'an businessman called Lim Loh (林路), who is the father of war hero Lim Bo Seng . Junction (road) A junction is where two or more roads meet. Roads began as a means of linking locations of interest: towns , forts and geographic features such as river fords . Where roads met outside of an existing settlement, these junctions often led to a new settlement. Scotch Corner

608-632: Is whether or not the roads cross at the same or different elevations . More expensive, grade-separated interchanges generally offer higher throughput at higher cost. Single-grade intersections are lower cost and lower throughput. Each main type comes in many variants. At interchanges , roads pass above or below each other, using grade separation and slip roads . The terms motorway junction and highway interchange typically refer to this layout. They can be further subdivided into those with and without signal controls. Signalized ( traffic-light controlled) interchanges include such " diamond " designs as

646-510: The Town Center at Aurora shopping center in Aurora, Colorado , United States (at 39°42′40″N 104°49′33″W  /  39.711189°N 104.825807°W  / 39.711189; -104.825807 ). A three-level SPUI is similar to a standard SPUI but includes an additional grade separation allowing for free-flowing through traffic on the crossroad; such through traffic thus bypasses

684-638: The diverging diamond , Michigan urban diamond, three-level diamond , and tight diamond. Others include center-turn overpass, contraflow left, single loop, and single-point urban overpass. Non-signalized designs include the cloverleaf , contraflow left, dogbone (restricted dumbbell), double crossover merging , dumbbell (grade-separated bowtie), echelon, free-flow interchange , partial cloverleaf , raindrop , single and double roundabouts (grade-separated roundabout ), single-point urban , stack , and windmill . Autobahnkreuz (literally "autobahn cross"), short form kreuz , and abbreviated as AK,

722-399: The righthand side. Due to the large intersection area, the traffic lights need a longer yellow and red phase to clear the intersection, and, even then, it may not be long enough for a bicyclist entering on green or yellow to make it across before opposing traffic gets a green. In general, SPUI designs should not be used where bicycle traffic is expected unless fairly substantial changes to

760-472: The "side road" at this interchange. The southbound carriageway of SR 7 bridges over the interchange, while its northbound carriageway remains at-grade. SR 7's left on- and offramps run between its carriageways, meeting the I-470 ramps at an at-grade intersection. The I-470 ramps proceed to a trumpet interchange with I-470. I-470 itself bridges over both carriageways of SR 7 a short distance north of

798-643: The EU it is estimated that around 5,000 out of 26,100 people who are killed in car crashes are killed in a junction collision, in 2015, while it was around 8,000 in 2006. During the 2006–2015 decade, this means around 20% of road fatalities occur at junctions. By kind of users junctions fatalities are car users, 34%; pedestrians, 23%; motorcycle, 21%; pedal-cycle 12%; and other road users, the remaining. It has been considered that several causes might lead to fatalities; for instance: A number of features make this protected intersection much safer . A corner refuge island,

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836-618: The I-470/SR ;7 ramps' intersection. This design was likely chosen not for cost savings but because the northbound carriageway of SR 7 is bordered by railroad tracks, commercial properties, and the Ohio River and because I-470 bridges the river just east of SR 7—a more conventional interchange design was likely more difficult to achieve. There is another such interchange in Millvale, Pennsylvania , near Pittsburgh , at

874-433: The SPUI is the inverted SPUI , in which the carriageways of the free-flowing road are separated, with left on- and offramps running between the carriageways and coming to a single at-grade intersection with the cross street. This can be built less expensively than a standard SPUI by allowing for shorter, simpler bridges at the interchange. However, this inverts the usual convention of placing carriageway on- and offramps on

912-422: The bridge approach, while the southbound carriageway had a continuous green T-intersection with the bridge. An offset SPUI is similar to a diamond interchange, however, by making two of the ramps flyovers or flyunders , all ramps are pushed to one side of the highway, where they meet the surface street at a single intersection. An example of this is the interchange between Interstate 225 and Alameda Avenue near

950-459: The design or special accommodations are provided. Pedestrians are usually not able to get through the intersection with one green light. It can take up to four cycles to walk through the entire length of a SPUI. Finally, SPUIs can be somewhat difficult to clear of snow. The large area in which lanes cross may have to be shut down to allow efficient and thorough cleaning lest a snowplow leave piles of snow, interfering with traffic and visibility in

988-448: The fact that all through traffic on the arterial street, as well as the traffic turning left onto or off the interchange, can be controlled from a single set of traffic signals . Due to the space efficiency of SPUIs relative to the volume of traffic they can handle, the interchange design is used extensively in the reconstruction of existing freeways as well as constructing new freeways, particularly in dense urban environments. Sometimes

1026-593: The free-flowing road is at-grade with but still separated from the side road, as found in a continuous green T- (or seagull) intersection . There is one such interchange in Pultney Township, Belmont County, Ohio , between State Route 7 (SR 7) and Interstate 470 (I-470) at 40°02′52″N 80°44′01″W  /  40.047657°N 80.733542°W  / 40.047657; -80.733542 . The ramps leading to and from I-470 run west of, but are not directly connected to, SR 7; these ramps form

1064-480: The freeway they are departing (if, for example, they realize that they have taken the wrong exit) within a SPUI. Three-phase traffic signals are required. Other interchange types designed for efficiency, such as the six-ramp partial cloverleaf and the diverging diamond , require just two signal phases. The first SPUI opened on February 25, 1974, along U.S. Route 19 ( State Road 55 ), which goes over State Road 60 east of Clearwater, Florida . It

1102-435: The intersecting roadways is able to turn simultaneously without crossing the path of the opposing left turns. Because traffic passing through the interchange can be controlled by a single signal, vehicles can clear the intersection much more quickly than in a diamond interchange (which requires two sets of traffic signals). SPUIs also allow for wider turns, easing movement for large vehicles, such as trucks and RVs. Furthermore,

1140-494: The junction between Pennsylvania Route 28 (PA 28) and the 40th Street Bridge . The northbound carriageway of PA 28 passes under the interchange, with lefthand ramps meeting at the bridge (the northbound entrance ramp does not provide direct access to PA 28). The southbound carriageway of PA 28 has a continuous green T-intersection with the bridge. A similar interchange exists in Coal Grove, Ohio , at

1178-587: The junction of U.S. Route 52 (US 52) with the Ben Williamson Memorial Bridge and the Simeon Willis Memorial Bridge , which cross the Ohio River and lead to and from Ashland, Kentucky , respectively. The eastbound carriageway of US 52 passes under the interchange, with lefthand exit and entrance ramps to the bridges. The westbound carriageway of US 52, which narrows to one throughlane, has

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1216-606: The low grade bike lanes in the roadway or higher grade and much safer protected bicycle paths that are physically separated from the roadway. In Manchester, UK, traffic engineers have designed a protected junction known as the Cycle-Optimised Signal (CYCLOPS) Junction. This design places a circulatory cycle track around the edge of the junction, with pedestrian crossing on the inside. This design allows for an all-red pedestrian / cyclist phase with reduced conflicts. Traffic signals are timed to allow cyclists to make

1254-404: The middle of the uncontrolled pavement. Additionally, if the wide area of uncontrolled pavement is on a bridge, as in the diagram, the snow cannot be pushed to the sides of the bridge as it may pose a hazard to the road underneath. This problem can be exacerbated by the comparatively large bridge width required by the SPUI. Given that a SPUI allows only left and right turns, drivers may not reenter

1292-408: The right side of the carriageway, instead placing them on the left side, usually considered the passing lane . There is also a variant of the inverted SPUI, which can be used when a side road ends at, rather than crossing, a free-flowing road. In this variant, one carriageway of the free-flowing road is grade-separated from the side road, as with a typical inverted SPUI, while the other carriageway of

1330-471: The two types of interchanges in terms of total collisions, the injury and fatality rates are notably lower for SPUIs than diamond interchanges. The major disadvantage of SPUIs over other types of road junctions is the increased cost due to the need for a longer or wider bridge. A freeway-under SPUI (as in the upper diagram) requires a wider bridge over the free-flowing road to make room for the compressed on- and offramps. However, this disadvantage poses less of

1368-474: The visually impaired. Medians can offer pedestrian islands, allowing pedestrians to divide their crossings into a separate segment for each traffic direction, possibly with a separate signal for each. Single-point urban interchange A single-point urban interchange ( SPUI , / ˈ s p uː i / SPOO -ee or / ˈ s p juː i / SPEW -ee ), also called a single-point interchange ( SPI ) or single-point diamond interchange ( SPDI ),

1406-532: Was designed by Wallace Hawkes, Director of Transportation Engineering at J. E. Greiner Company (later URS Corporation ), who has been called the "granddaddy of the urban interchange". This design has since been altered to include frontage roads in each direction. Several SPUIs, built in the 1970s and later, are located on German autobahns, like the A40 , A42 , A44 , A46 , A57 , A59 , and A113 in Berlin . There

1444-521: Was to add traffic control devices, such as stop signs and traffic lights that regulated traffic flow. Next came lane controls that limited what each lane of traffic was allowed to do while crossing. Turns across oncoming traffic might be prohibited, or allowed only when oncoming and crossing traffic was stopped. This was followed by specialized junction designs that incorporated information about traffic volumes, speeds, driver intent and many other factors. The most basic distinction among junction types

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