[attlawqa]

Just an FYI, not my opinion or view on them..

Mini roundabouts

After developing the offside priority rule, Frank Blackmore, of the UK's Transport Research Laboratory, turned his attention to the possibility of a new type of roundabout that could be utilised at sites with limited space to use a conventional roundabout.

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 these smaller junctions to avoid the use of signals, stop signs or the necessity to give way in favour of one road of traffic. Mini-roundabouts can be a painted circle or a low dome but must be fully traversable. 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 terms of right of way but can give different performance with regard to driver behaviour. Mini-roundabouts are sometimes grouped in pairs (a double mini-roundabout) or in "chains", making navigation of otherwise awkward junctions easier. In some countries there are different road signs used to distinguish mini roundabouts from larger ones.
Mini-roundabouts are common in the UK and Ireland, as well as Irapuato in Mexico and Mount Royal and Rosedale in Calgary, Canada.
A slightly larger version of a mini-roundabout, sometimes called a "small or midi roundabout", is designed with a raised centre surrounded by a sloped "overrun area" of a different colour from the roadway and up to a metre wide called a "truck apron" or a "mountable apron". The truck apron's design discourages small vehicles from taking a shortcut over it while at the same time allowing the mini-roundabout to more easily accommodate the turning radius of larger vehicles (such as a truck which may have to navigate the roundabout).
In the UK the maximum permissible diameter of the central painted circle of a mini-roundabout is 4m. Whilst it may be physically possible, it is illegal for vehicles which are able to circulate around the central circle of the roundabout to go over the painted circle, or around the wrong way. Vehicles should treat the painted circle like a solid island and proceed around it.[35] (In practice, many motorists ignore these rules, especially when traffic is light).[citation needed] Some local authorities have installed double white lines around the painted circle to indicate this, but these are not permitted under UK traffic signs regulations without authorisation from the Secretary of State for Transport . The centre island also must be able to be over-run by larger vehicles.
At Hatton Cross roundabout, close to London Heathrow Airport, five small ‘mini-roundabouts’ have been constructed where the roads join/leave the main roundabout, allowing traffic to circle the main roundabout in both directions - clockwise in the outer lane(s) and anti-clockwise in the inner lanes.