(Redirected from Roundabouts): ''This article is about the road junction. For other uses, see
Roundabout (disambiguation)''.
A 'roundabout' or 'rotary' is a type of
road junction (or
traffic calming device) at which
traffic enters a stream around a central island after first yielding (giving way) to the circulating traffic. In the United States it is technically called a "'modern roundabout'", to emphasize the distinction from the older, larger type of
traffic circle (though some Americans still refer to modern roundabouts as '"Traffic Circles"'). In many parts of the
English Midlands roundabouts are commonly referred to as "islands".
Overall, roundabouts are statistically safer than both traffic circles and traditional intersections, with the exception that cyclists have a significantly increased crash rate at large roundabouts. Roundabouts do not cope as well with the traffic on
motorways,
highways, or similar fast roads.
Difference between roundabouts and traffic circles
Roundabouts are sometimes referred to as
"traffic circles", but a technical distinction was made in some jurisdictions between roundabouts and traffic circles in the mid-
1960s. Starting in that decade, research in the
United Kingdom found that circular intersections with certain geometric characteristics and traffic control schemes tended to be safer than those without them. The key differences are:
| Roundabout | Traffic Circle |
|---|
| Entering vehicles yield | Stop sign, stop signal, or giving priority to entering vehicles |
| Vehicles in the roundabout have priority over the entering vehicle | Allow weaving areas to resolve conflicted movement |
| Use deflection to maintain low speed operation | Some large circles provide straight path for higher speed |
| No parking is allowed | Some large circles permit parking within the circle |
| Pedestrians are (usually) prohibited from the central island | Some large circles allow pedestrians on central island |
| All vehicles circulate around the central island | Mini-traffic circles with left-turning vehicles passing to the left1 of the central island. |
1 For countries that drive on the right-hand side of the road.
(Source for table: Oregon Department of Transportation [1])
|
In the
United Kingdom the term 'traffic circle' is not used, and all types are known as roundabouts (but see
mini-roundabouts and
magic roundabouts below). In the
United States, circular intersections that meet the design standards shown in the table above are termed "modern roundabouts," to distinguish them from older rotaries or traffic circles. In
Massachusetts, rotaries are nearly always built to the standards of a British roundabout, and a "roundabout" refers to an especially small rotary with crosswalks, between high-traffic roads.
[1]
History and safety
The first modern roundabout was constructed in
Paris around the
Arc de Triomphe in
1901, closely followed by
Columbus Circle in
New York City in 1904. The first British roundabout was five years later, in
Letchworth Garden City in 1909 - originally intended partly as a traffic island for pedestrians
[2]. However, the widespread use of roundabouts began when
British engineers re-engineered the traffic circle in the mid-
1960s to overcome its limitations of capacity and for safety issues. Unlike traffic circles, roundabouts operate with yield control to give priority to circulating
traffic and eliminate much of the driver confusion associated with traffic circles and driver wait associated with
junctions that have
traffic lights. Roughly the same size as signalled intersections with the same capacity, roundabouts also are significantly smaller in diameter than traffic circles, separate incoming and outgoing traffic with
pedestrian islands and therefore encourage slower and safer speeds (see
traffic calming).
Roundabouts are safer than both traffic circles and traditional intersections—having 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities (according to a study of a sampling of roundabouts in the
United States, compared with the intersections they replaced). Roundabouts also reduce points of conflict between pedestrians and motor vehicles and are therefore considered to be safer for them. However, roundabouts, especially large fast moving ones, are unpopular with some cyclists. This problem is sometimes handled on larger roundabouts by taking foot and bicycle traffic through a series of
underpasses.
In addition to improved vehicle and pedestrian safety, and in spite of lower speeds, roundabouts dramatically outperform traffic circles in terms of vehicle throughput and, because a roundabout's circular traffic is always moving, they outperform ordinary junctions with traffic signals as well.
Multi-lane and large roundabouts can be hazardous for cyclists. An analysis of the national crash database
[3] in
New Zealand for the period 1996-2000 shows that cyclists were involved in 26% of the reported injury crashes at roundabouts, compared to 6% at traffic signals and 13% at priority controlled intersections. The most common roundabout crash type for cyclists involves a motor vehicle entering the roundabout and colliding with a cyclist who is already travelling around the roundabout (generally just over 50% of all cyclist/roundabout crashes fall into this category). The next most common crash type involves motorists leaving the roundabout, colliding with cyclists who are continuing further around the roundabout carriageway. Designs that have
marked perimeter cycle lanes are found by research data to be even less safe than those without them.
If the adjacent cross-walks are not properly designed, there are increased risks for persons with visual impairments, because of the speed at which traffic exits the roundabout. This issue has led to a conflict in the United States between the visually impaired and
civil engineering communities; the visually impaired have taken the position that roundabouts (rather than signal-controlled crossings) are acceptable only if there are pedestrian crossings with lights at ''each'' road connecting to a roundabout. Although such crossings would reduce the possibility that a
blind pedestrian might be run over by vehicles entering or exiting the roundabout at unsafe speeds, they would also increase the cost of a roundabout and decrease its throughput.
In addition, roundabouts do not cope well with the traffic on motorways or similar roads, leading to long queues. Britain's strategic road network has many isolated roundabouts on otherwise almost motorway-like roads (for example, A1/A421) and even on a few motorways (for example, the
A601(M),
A627(M), and
M271 have roundabouts on the main line). Some of these roundabouts, as well as other busy roundabouts, have had traffic lights added and are termed "signal controlled roundabouts".
Roundabouts are not suitable for junctions where the exits suffer from
traffic congestion. Congestion on one exit commonly blocks a roundabout and spreads to all entering directions. The roundabout of
Kwai Tsing Interchange in
Hong Kong was replaced by a large
box junction with
traffic lights after recurring area traffic congestion when numerous container trucks journeyed to
Kwai Chung Container Port after a
typhoon.
Types of roundabout
Large roundabouts such as those used at motorway intersections typically have two to four lanes around the central hub, and frequently have traffic lights regulating flow during peak hours.
Some roundabouts have a divider between traffic turning from one road onto an adjacent one, and traffic within the roundabout, enabling those making such turns to bypass the roundabout entirely. Another type of roundabout is the through-about roundabout or "hamburger" junction. This type of roundabout enables straight-through traffic on one road to cross over the central island, whilst all other traffic must drive around the island. As a consequence this junction must always be controlled by traffic lights. Examples of this type exist in
Bracknell,
Nottingham and
Reading, as well as on the
N2/
M50 intersection in
Dublin,
Ireland.
Gyratory system
The term "gyratory" (for example, the
Hanger Lane Gyratory System) is sometimes used in England when a roundabout is large and has non-standard lane markings or priorities; in fact, they are more like traffic circles
[3].
Mini roundabouts
A 'mini-roundabout' in the United Kingdom, where a painted white circle is used for the centre. The arrows show the direction of traffic flow.
Mini-roundabouts exist at smaller intersections to avoid the use of signals, stop signs or the necessity to yield in favor of one road of traffic. Mini-roundabouts can be a painted circle, a low dome, or often are small garden beds. Painted roundabouts and low domes can easily be driven over by most vehicles, which many motorists will do when there is no other traffic, but the practice is dangerous if other cars are present. Mini-roundabouts work in the same way as larger roundabouts in term of right of way. They can often come in "chains", making navigation of otherwise awkward junctions easier. There are usually different
road signs used to distinguish mini roundabouts from larger ones.
Mini-roundabouts are also common in
Irapuato, Mexico, usually marked with a tiny grassy circle enclosed with sidewalk edges, and in
Calgary, Canada's inner-city
Mount Royal and Rosedale neighbourhoods, where mini-roundabouts recently replaced intersections formerly controlled by stop signs to combat increasing cut-through traffic.
A slightly larger version of a mini-roundabout, sometimes called a "small roundabout", is designed with a raised center surrounded by a sloped "overrun area" of a different color from the roadway and up to a meter in thickness called a "truck apron". The truck apron's design discourages small vehicles from shortcutting over it while at the same time allowing the mini-roundabout to more easily accommodate the turning radius of larger vehicles.
In the U.K the maximum diameter permissible of a mini-roundabout is 4m. Whilst it may be physically possible, it is illegal for vehicles like cars, which can turn around the mini-roundabout, to go over the painted island, or around the wrong way- vehicles should treat it like a solid island and proceed around it. Certain local authorities have installed double while lines around the island to indicate this, but these are not permissible. The centre island also must be able to be over-run by larger vehicles. If this is not possible, perhaps due to plants, or street furniture it is considered a small roundabout not a mini roundabout and as such must adhere to the stricter roundabout guidelines.
Raindrop or peanut shaped roundabouts
These roundabouts do not form a complete circle and are in a "raindrop" shape. They are appearing at Interstate interchanges to provide a free-flowing left turn to the on-ramps and eliminating the need for turn signals and lanes. Since the on and off-ramps are one-way, the need for a complete circle is not necessary. This means that drivers entering the roundabout from the bridge do not need to yield and prevents queuing on narrow, two-lane bridges. These roundabouts have been used at new interchanges so that a two-lane bridge can be built for less cost than a three-lane, as well as replacing traffic signals that are inefficient without a turning lane.
Roundabouts on motorways
While roundabouts do not usually interrupt motorways in the UK or Ireland, a common type of motorway intersection (suited only for lower volumes of traffic) consists of a
grade separated roundabout above or below the main motorway, accessed via sliproads. Most intersections on
Dublin's
M50 motorway ring-road use this configuration — although several junctions have a greater volume of traffic than the capacity such roundabouts can accommodate.
An additional improvement is the '3-level stacked roundabout' — this is a roundabout interchange where ''both'' roads are grade separated. In the
United Kingdom, the
M25/
A3 and
A1(M)/
M18 interchanges are examples of this type. These junctions however have less capacity than a full
free-flow interchange. A similar design to this is the
three-level diamond interchange.
The
A52 motorway in Switzerland links with three sections of road near Hinwil heading toward
Hinwil,
Forch and
Rapperswil. The intersection takes shape in the form of a massive roundabout on the motorway. However, the sign for a roundabout is not used and a speed limit of 80 km/h (50 mph) applies. The size of the roundabout conceals the fact that it is a roundabout at all.
The
A7 motorway, also in Switzerland, also has a motorway roundabout (at its terminus in
Kreuzlingen), but it is smaller in size.
Massachusetts Route 128, a motorway/
freeway in the
United States, also has two large
at-grade roundabouts (or ''rotaries'' as they are called in that state) in the city of
Gloucester. They are signed as Exits 10 and 11. Roundabouts in
Massachusetts follow the same general rule as in the UK, with circling traffic receiving right of way.
There also was a former roundabout at the southern terminus of
Route 3, a motorway linking
Cape Cod to
Boston; directly opposite is another motorway, the start of the
Mid-Cape Highway section of
US 6 heading over the
Sagamore Bridge. Due to the small size of the roundabout, and the fact that Routes 3 and 6 make up the shortest way to get between the Cape and Boston, traffic tie-ups and accidents were common, especially in the
summer months, when drivers from other states were often confused at how to navigate the roundabout. This roundabout was replaced with a standard motorway interchange during a three-year conversion project which concluded in
2007.
In the city of
Malmö,
Sweden, there is a roundabout connecting two motorways, "Autostradan" from
Lund, and the "Inner ring road". It is signposted as a motorway through this roundabout. Today these two motorways are considered local, but before year 2000 they were part of the European roads
E6,
E20 and
E22.
Controlled roundabouts
Some bridges on
Beijing's
2nd Ring Road are controlled by traffic lights. While it may appear to defy the roundabout system at first, it works well to control the flow of traffic on the bridges, which themselves are two viaducts creating a roundabout suspended over the ring road itself.
Signal controlled roundabouts are common in
Great Britain and
Ireland, where they have been introduced in an attempt to alleviate traffic problems at over-capacity roundabout intersections or to prevent some flows of traffic dominating others (around the
M50 in
Dublin for example).
"Magic" roundabouts
The town of
Swindon in
Wiltshire,
England is known for its "
Magic Roundabout". This roundabout is at an intersection of five roads and consists of a two-way road around the central island with five mini-roundabouts where it meets the incoming roads. Traffic may proceed around the main roundabout either clockwise via the outer lanes, or anti-clockwise using the inner lanes next to the central island. At each mini-roundabout the usual clockwise flow applies.
Similar systems are found in various places in England, most famously the
Moor End roundabout in
Hemel Hempstead (
Hertfordshire), which has six intersections; but also one in
High Wycombe (
Buckinghamshire)
[4] and the
Denham Roundabout in
Denham (
Buckinghamshire), the
Greenstead Roundabout in
Colchester (
Essex) and the Sadler's Farm Roundabout in
Benfleet (
Essex); "
The Egg" in
Tamworth, (
Staffordshire); and the Hatton Cross Roundabout in
London [5]. Magic roundabouts are also known as "Ring Junctions".
Roundabouts with trams
Most notably found in inner
Melbourne, particularly in the inner suburban area of
South Melbourne, where the
tram network is extensive. Tram tracks always pass through the central island of these roundabouts. They can be worrying for inexperienced drivers, as they must give way, not only to vehicles coming towards them from their right, but also to trams coming at them from right-angles.
Having trams pass through a small roundabouts is not a problem; through larger roundabouts it can be difficult, particularly when there is a tram junction (i.e. the tram may do more than simply pass straight through the intersection). In these cases, the roundabouts are very large, and often have tram stops in the middle.
Flemington Junction is the most notorious intersection of this nature, containing a tram-stop, pedestrian crossings, three entering tram lines, traffic signals to stop vehicular traffic at each crossing point when a
tram is due, service roads and
pedestrian crossing.
There are a few larger roundabouts in
Brussels where several tram routes converge from different directions, and the tram lines are laid around the roundabout allowing the trams to follow the same path as other traffic.
In
Dublin,
Ireland, the
Red Cow ("Mad Cow") roundabout at the
N7/
M50 intersection is particularly infamous. It is a grade-separated motorway junction, and is signal-controlled with secondary lanes (separate from the main roundabout) for those making left hand turns. The junction, the busiest in Ireland, had tram lines added to it with the opening of the
LUAS system in
2004. The tracks pass across one carriageway of the N7, and across the southern M50 sliproads. Trams pass at a frequency of every 5 minutes at rush hour.
In
Gothenburg,
Sweden the roundabout and Korsvägen
tram stop (the Crossroad) at the
Trade fair is of this type, and is rather infamous in the city. It is heavily trafficked by cars, and about one tram or bus per minute passes.
In
Wrocław,
Poland tram passes through Powstańców Śląskich Roundabout, having a stop in the roundabout (north-headed track).
In
Kiev,
Ukraine an interchange of two "
fast tram" lines is done below a roundabout.
Oslo,
Norway also has many roundabouts with
tram tracks passing through; for example at Bislett, Frogner plass,
Sinsen, Solli plass and Storo.
In
Wolverhampton,
UK, the
Midland Metro tram passes through the centre of a roundabout on approach to its terminus at St Georges. This also happens in
New Addington on the
Croydon Tramlink on Old Lodge Lane at the junction to King Henry's Drive.
An underpass in
Sheffield,
UK allows the tram to travel below a major roundabout, avoiding what would otherwise be a serious hindrance to traffic.
Hamburger roundabout/throughabout/cut-through roundabout
These resemble a normal roundabout but are signalised and have a straight-through section of carriageway for one of the major routes. The ''hamburger'' name derives from the fact that the plan view resembles the cross-section through a
hamburger. There are two such examples on the A580 East Lancashire Road in
St Helens, England, one at
Haydock Island in Merseyside (which also features the M6 passing overhead), the second is on the
Astley/Boothstown border near to Manchester. More examples are the A6003 at
Kettering and the A538 near Manchester Airport
[6]. Yet another can be seen at the junction of
Morley Drive and Alexander Drive in Perth, WA, Australia. An example of such an intersection in the United States can be found on the
Revere Beach Parkway in
Everett, Massachusetts.
Roundabouts and Cyclists
Cycle facilities at roundabouts
Research has shown that even in large circular intersections that lack modern roundabout design features, a high rate of bicycle/motor vehicle crashes occurs when bicyclists are riding around the outside. Design guidance for modern roundabouts recommends terminating cycle lanes well before the entrances, so bicyclists merge into the stream of motor traffic.
A 1992 study from the
German Transport Ministry's research institute has cast particular light on this issue. The study found that bicyclists' risk is high in all such intersections, but it is much higher when the intersection has a marked bicycle lane or sidepath around its outside ''(see "Marked perimeter cycle lanes" below)''. The results of this study concerning circular intersections are summarized on a
web site (in
German, but partially translated below). A report about accidents at four-arm roundabouts was published by the
UK Transport and Road Research Laboratory (TRRL) (now
TRL) in 1984.
Collisions typically occur when a motorist is entering or leaving the circular roadway. A motorist entering the circular roadway must yield to traffic in it, but such traffic will generally keep away from the outside of the circular roadway (as with a vehicle in the photo) if passing an entrance. A bicyclist close to the edge of the roadway is not in the usual position where an entering motorist expects to look for circulating traffic.
When exiting the circular roadway, a motorist must look ahead to steer, and to avoid colliding with another vehicle ahead or with
pedestrians in a
crosswalk. As the circular roadway curves away from the exit, the path of a vehicle exiting the circular roadway is relatively straight, and so the exiting motorist may often not need to slow substantially. However, if it is necessary to yield to a bicyclist riding around the outside, the exiting motorist must look toward the rear, to the outside of the intersection. With many vehicles, such as
vans, the driver's view in this direction is obstructed. The task burden of the motorist is therefore substantially increased if bicyclists ride around the outside. The resulting conflicts, and more frequent requirements for motorists to slow or stop, also reduce the efficiency of traffic flow which is one of the major advantages of the circular intersections. Cycle lanes around the outside of circular intersections are therefore falling out of favor.
Marked perimeter cycle lanes
An early attempt to deal with the problem was to mark preferential lanes for cyclists, as in the picture (right). With cycle lanes,
bicyclists do not merge into the flow of motor traffic in the roundabout, but rather, they travel around the outside, relieving them of the requirement to merge. The colored road surface and edge lines of the cycle lanes indicate that
motorists are required to yield to bicyclists at all locations where their paths may cross.
Modern design guidance
The special features of modern roundabouts, including splitter/diverter islands and small diameter of the circular roadway, decrease the speed of motor traffic and so reduce the risk of collisions for bicyclists as well as motorists below that of conventional intersections. Design guidance for modern roundabouts recommends terminating cycle lanes well before the entrances, so bicyclists merge into the stream of motor traffic. Bicyclists who lack the skill and confidence to do this may use the crosswalks as pedestrians. Modern design guidance also recommends placing the crosswalks far enough from the roundabout so that at least one exiting vehicle can wait without blocking the circular roadway.
See the
New York State DOT Interim Requirements and Guidance or the
United States DOT Informational Guide.
Examples of roundabouts
★
Elephant and Castle,
London
★
The Plain, Oxford
★
St George's Circus, London
★
Place Charles de Gaulle (Place de l'Étoile),
Paris — 12 roads regularly spaced at 30° intervals around the
Arc de Triomphe
★
Los Alamitos Traffic Circle,
Long Beach, California
★
Glorieta de Bilbao,
Madrid — a star shaped roundabout
★
Columna de la Independencia Rondabout in
Paseo de la Reforma,
Mexico City
★ Set of 5 modern roundabouts at exit 12 off
Interstate 87 in
Malta, NY (completed May, 2007)
Miscellany
An
IMAX cinema built in a roundabout
★ The
Lambeth Bridge Roundabout in
London was featured in the film
National Lampoon's European Vacation.
★ The first UK roundabout was built in
Letchworth Garden City, in 1909.
[4]
★ The
Brunel Bridge Roundabout in
Slough was made famous by its appearance in the opening titles of the
Ricky Gervais sitcom ''
The Office''.
★ The Kinsale Road Roundabout in
Cork,
Ireland is a very large and irregularly shaped, three lane, signal controlled roundabout. The roundabout is situated on the
N25 southern ring road dual carriageway, at the intersection with a dual-carriageway to the city centre, a road to Bishopstown, and the
airport or
Kinsale road. With the huge traffic volumes at the intersection, the dangerous and difficult navigation of the roundabout had given rise to the "Magic Roundabout" nickname and at times traffic jams of a kilometer in length were not uncommon, especially during peak periods. However this roundabout has been upgraded to a grade-separated junction where the N25 now passes over it.
★ The roundabout at the junction of Tyndall Street and Ocean Way in
Cardiff has
cubes and other
geometric shapes constructed from
road signs.
(Google Map)
★
Crawley,
West Sussex has a large rectangular roundabout which contains a hotel in the centre, giving rise to the address, "The Squareabout, Crawley".
★
Mooroolbark,
Melbourne contains a triple-roundabout
[7], that is, three consecutive roundabouts, on Hull Rd. They were built to replace a dangerous area where three secondary roads joined Hull Rd at separate places within 200 m. Each roundabout allows drivers to turn onto or off from one of the three secondary roads.
★ Two roundabouts in the Melbourne metropolitan area,
Highett [8] and
Brighton [9], have
heavy rail crossing the roundabout and through the inner circle.
Boom barriers protect the rail from oncoming traffic at the appropriate points in the roundabout.
★
St Kilda Junction,
St Kilda,
Melbourne, was once an uncontrolled seven-street roundabout also containing a
tram junction in the middle; it was drastically altered in the 1970s to make it a two-level, light-patrolled intersection.
★ One of the most famous landmarks in
Guadalajara,
Mexico is the
Minerva Fountain Roundabout, which contains a huge fountain surrounding a statue of the Roman goddess
Minerva. It is in the middle of a series of 3 consecutive roundabouts, located in the intersection of 5 avenues: López Mateos, Vallarta, López Cotilla, Agustín Yáñez and Golfo de Cortez. A long tunnel runs under all the three roundabouts.
★ In
Birmingham, United Kingdom,
Haden Circus is a roundabout with only half of the central island grassed over, the other half being demarcated by concrete blocks. This originates from when Formula 3 racing was held on the city streets.
★ The
Australian cities of
Griffith in
New South Wales, and
Albany in
Western Australia contain no traffic lights, only roundabouts.
★ The city of
Milton Keynes in the United Kingdom is famous for having grid roads which have roundabouts at almost every intersection.
★ In
Dundee, Scotland, roundabouts are called "circles" by the locals.
★ The Shepherd and Flock roundabout
(Google Map) in
Farnham,
Surrey extends to over 10 acres with 17 houses and a pub that lie within, making it one of the largest inhabited roundabouts in the UK. An oddity of 1960s road planning has left the 17 houses and the pub encircled by several lanes of tarmac that connects
Guildford to
Winchester (
A31). The completed roundabout was therefore named after the pub "The Shepherd and Flock".
[5]
★ The
Simpsons once took a trip to the
United Kingdom and became stuck circulating a roundabout. They fought their way out eventually, only to crash into the Queen's carriage.
★ A
roundabout dog is a homemade street installation placed in roundabouts, a phenomenon that occurred all over
Sweden in
2006.
See also
★
Roundabout Appreciation Society
★
Traffic circle
References
★ R. Schnüll, J. Lange, I. Fabian, M. Kölle, F. Schütte, D. Alrutz, H.W. Fechtel, J. Stellmacher-Hein, T. Brückner, H. Meyhöfer: ''Sicherung von Radfahrern an städtischen Knotenpunkten'' [''Safeguarding bicyclists in Urban Intersections''], Bericht der Bundesanstalt für Straßenwesen zum Forschungsprojekt 8952, 1992
★ http://bernd.sluka.de/Radfahren/Vortragsfolien.html Scroll to the section labeled "Kreisverkehr". A translation of the text reads: Graphic from ''Sicherung von Radfahrern an städtischen Knotenpunkten'' [''Safeguarding bicyclists in Urban Intersections''], (BASt, 1992). Accident numbers in large circular intersections with different bicycle facilities show: 1. why there should be no sidepaths or bike lanes in these intersections; 2. Even when bicyclists use the roadway, their risk is relatively high in these intersctions.
★ See for example ''Modern Roundabouts, an Informational Guide'', http://www.tfhrc.gov/safety/00068.htm and the section on roundabouts in the US Manual on Uniform Traffic Control Devices, http://mutcd.fhwa.dot.gov/HTM/2003/part3/part3b2.htm#figure3B27 (you may have to scroll down the page).
★ Maycock, G., and Hall, R. D. (1984). "Accidents at 4-Arm Roundabouts." TRRL1120, Transport and Road Research Laboratory (TRRL), Crowthorne, England.
★ Wilke, A. and Koorey, G. (2001). ''How Safe are Roundabouts for Cyclists?'' In TranSafe Issue 5, April 2001. Wellington, NZ. http://www.landtransport.govt.nz/transfund/publications/transafe/transafe-05.pdf
1. Commmonwealth of Massachusetts Driver's Manual [2]
2. Roundabout Magic BBC News
3. http://www.alaskaroundabouts.com/history.html
4. Sign of the Times Letchworth Garden City Heritage Foundation
5. Telegraph - At home in the middle of a roundabout
External links
★
DLZ Roundabouts
★
Roundabouts in North America
★
★
Roundabouts: An Informational Guide by the U.S.
Federal Highway Administration, FHWA-RD-00-67, June 2000 (or see the
entire pdf in one file)
★
★
Secion 3B.24 from the U.S.
Manual on Uniform Traffic Control Devices
★
★
Roundabouts: Interim Requirements and Guidance by the New York State Department of Transportation, June 20, 2000
★
The Magic Roundabout of Swindon
★
Multilane Roundabouts an Information Sheet
★
The Hanger Lane Gyratory System, London, England
★
The Kinsale Road Roundabout, Cork, Ireland, on Google Maps
★
How to use UK roundabouts, video tutorials
★
Mini-roundabouts - Getting them Right
★
Washtenaw County Road Commission's Modern Roundabout Information
★
Roundabout Information and related
CBC Article and
Video
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