Accidents are likely to happen if drivers do not exercise greater judgment when using multi-lane roundabouts, an expert has warned.
“Roundabouts are a good alternative to traffic signals in a variety of instances. But, when the traffic volume is high multiple lanes are needed on one or more of the intersection approaches and roundabouts are a less attractive solution because of the possibility of accidents,” said Ademola Ilori, safety expert at the Traffic Department.
In fact, most drivers on Qatar roads do not understand the lane use rules that are associated with multi-lane roundabouts. This is true because drivers are not exposed to multi-lane roundabouts during either driver training or during their domestic driving experience.
By examining the example multi-lane roundabout shown in Figure 1, one can understand the “lane discipline” required for safe operation. In this example, three of the four legs of the roundabout (the north, south and west) have multiple-lane approaches. Much like a signalised intersection, pavement arrows show the allowable movements that can be made from a given lane.
At a standard four-leg multi-lane roundabout like the one shown in Figure 2, pavement arrows have the following meaning:
Right arrow: must exit quarter of the way around the roundabout
Through arrow: must exit half of the way around the roundabout
Left arrow: must exit three-fourths of the way around the roundabout or make a U-turn
Combination right/thru arrow: can exit quarter or half of the way around the roundabout
Combination left/thru arrow: can exit half or three-fourths of the way around the roundabout
Combination left/through/right arrow: can exit anywhere around the roundabout.
Just as you wouldn’t think of going straight from a left turn only lane at a signalised intersection, those familiar with multi-lane roundabouts wouldn’t think of exiting half of the way around the roundabout if they entered the roundabout via a lane containing a left turn pavement arrow.
Once the “lane discipline” rules of multi-lane roundabouts is learned (and obeyed) by all motorists, then these roundabouts can safely carry substantial volumes of traffic. However, if only a few of the motorists using the roundabout don’t understand this lane discipline, then the clear potential exists for someone to exit the roundabout from the wrong lane and cause a sideswipe accident.
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