Q. I can’t understand why the right-hand lanes on Smithfield Avenue, in both directions, aren’t right-turn-only lanes onto Route 95 south. Smithfield Avenue is virtually a divided street, and there is no cross traffic. The light is only for traffic coming off Route 95 to turn left or right onto Smithfield Avenue. Especially frustrating is crossing the bridge, trying to get on Route 95, and having a car in front of me that could just as easily have been in a left dedicated straight-ahead lane.

A. Recently, a project was completed at the intersection of Smithfield Avenue with the Route 95 south ramps. As a part of this project some alternative traffic patterns were considered for this intersection. After looking at the number of vehicles that use the intersection and where they are going, such as straight through the intersection or making a right turn, the Department noticed that twice as many vehicles were traveling through the intersection versus making a right turn on the east- or west-bound approaches.

During this analysis the intersection in its original configuration and potential alternative configurations were rated using a standard system for road rating used nationally called Level of Service (LOS). LOS is a measure of effectiveness by which traffic engineers determine the quality of service of the transportation infrastructure.

The current intersection configuration is the one that had the best rating without hurting the flow of other nearby intersections.

Yield indicators

Q. Yield indicators painted on the road surface are helpful. However, although they are relatively new, the markings are beginning to show signs of deterioration. What’s up? Also, why aren’t the ground indicators placed reasonably before the yield sign to give the motorist an indication that the yield is ahead?

A. The relatively new on-ground yield indicators, the arrows pointing toward on-coming traffic that are painted on the road are called yield lines, and are positioned based on national standards.

The Manual on Uniform Traffic Control Devices (MUTCD), a Federal Highway Administration publication, sets the nationally accepted standards for all traffic control devices (i.e. signs, pavement markings, traffic signals, etc.). All 50 states follow this manual so that there is uniformity when traveling from state to state.

Every detail about this pavement marking is explained in the MUTCD including the size of the triangles, the space between triangles, and the distance the line is from the up-coming yield sign.

Pavement markings on state roads are re-painted every two years. This includes yield pavement markings.

Dana Alexander Nolfe, chief public affairs officer for the state Department of Transportation, answers questions of general interest posed by Journal readers about state roads and other state transportation matters.

The DOT is responsible for the state’s transportation infrastructure, which includes highways, bridges, traffic signals and bikeways.

Questions are answered in the order they are received, and there may be a delay in answering.

To ask a question that would also be of interest to other readers, send a letter to Ask RIDOT, Features Department, The Providence Journal, 75 Fountain St., Providence, RI 02902. You can also e-mail your question to projocars@projo.com. Please put “Question for the DOT” in the subject field.

Questions or complaints of a specific nature should be posed to the DOT directly and will not be answered in this column.