A deficiency of roundabouts in urban areas arises when lengthy delays occur on one orrnmore legs of the roundabout. This event occurs when the entering and circulating volumes are notrnevenly spread, typically during the peak periods when traffic flows have a predominantly directionalrncharacteristic. These conditions develop a negative public opinion about roundabouts that ignorernthe safety and capacity benefits that roundabouts provided for the majority of the day.rnIntroducing traffic signal control to a roundabout is a technique that can be used to overcomernproblems associated with uneven traffic flows during peak periods. However, the form of signalrncontrol, its operation details and its impact on all road users all need to be considered before it canrnbe adopted for application at a roundabout.rnA conceptual analysis model has been developed by Akcelik and Associates Pty Ltd (May 2001) tornanalysis roundabouts with metering signals. This model was tested using a range of data to verifyrnits operation and to test its robustness.rnUsing the results obtained from the model, a set of guiding principles was developed for thernappropriate use of metering signals at roundabouts.
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