The new Arnold Drive roundabout at Agua Caliente Road was put into use Sept. 18, but motorists unfamiliar with its design were demonstrating confusion last week about how to proceed through it.

Some drivers paused at the various entry points thinking they first had to stop. Others stopped in confusion once inside the circular lane, seemingly unsure of which positions had right of way.

According to state transportation guidelines, vehicles first in the roundabout have right of way, successive vehicles must yield to those present, and no vehicles should stop while in the traffic circle, except to avoid collisions. If emergency vehicles are approaching the circle, motorists should not pull over inside the roundabout but should proceed to the nearest exit, turn out of the circle and then pull over.

The simplest procedure when approaching the roundabout is to look left, yield if necessary, proceed with caution, moving to the right and exiting at the desired point.

According to Rob Silva, the Sonoma County Road Department Operations Manager, the roundabout remains under construction but temporary striping has been put down to open the project to traffic while construction continues. Larger trucks, particularly transfers, are having a hard time staying within the temporary striping, Silva reported in an email. This week the concrete contractor is expected to begin forming the interior structures and larger trucks will have a problem driving around the form boards, he said. Larger trucks are advised to use alternate routes due to narrow turning movements during construction, Silva advised.