Questions and answers about the Blinker intersection

Posted September 21, 2006

(The following was prepared by the Martha's Vineyard Commission staff, at the request of Duncan Ross, chairman of the Oak Bluffs selectmen and forwarded to The Times by MVC executive director Mark London, who says the MVC has not taken a position on the question of how to resolve the traffic issues at the Blinker intersection. Copies of The Blinker Report are available at town libraries and downloadable from the MVC web site.)

Q. Is it true that, with a roundabout, trucks wouldn't be able to go through the Blinker intersection, and they would have to go through West Tisbury to go from Vineyard Haven to the airport?

A. This is not correct. The roundabout, and all five alternatives that were studied by the town of Oak Bluffs, would be designed to handle trucks of every legal size that travel on public roads in Massachusetts. The only impact of a roundabout on trucking is that trucks, like all vehicles, would not be held up in congestion; even during summer peak hours, the average delay would be reduced to a few seconds.

Q. Why would we install a rotary at the Blinker? I hate them on the Cape and they are being removed in other locations.

A. The option that is being studied is not an old-style rotary, which is large scale, high speed, multi-lane with weaving movements, and dangerous. The modern roundabout that is being looked at is small scale, low speed, single-lane, and extremely safe. The outer extent of the paved area would be about the same as the intersection is today; however the middle part would be planted with shrubs.

Q. Wouldn't a traffic light or a right-hand turn heading towards the airport be safer?

A. Both these options would be more dangerous than a roundabout. The accident rate for traffic lights is 64 percent higher than that of a roundabout for all crashes, four times greater for injury-producing crashes, and 10 times higher for incapacitating or fatal injuries (Source: Insurance Institute for Highway Safety). Roundabouts are safer because it is clearer who has the right of way and, since all vehicles travel in the same direction at very slow speed, the rare accident is minor. (A December 2002 report by the Maryland Highway Administration indicates that 15 single-lane roundabouts have greatly improved intersection safety in that state with a 100 percent decrease in the fatal crash rate, a 60 percent decrease in the total crash rate, an 82 percent reduction in the injury crash rate, and a 27 percent reduction in the property damage-only accident rate.)

With respect to adding a right-turn lane to the four-way stop, MS Transportation - which did the original study of the intersection for the town of Oak Bluffs - recommended against this option for safety reasons, both for vehicles and the conflict with the bicycle path. Greenman-Pederson - who worked on the design of the five options at the Blinker intersection - said, "From a safety point, the‑right turn under stop control could actually be more hazardous. A stop control is effective for controlling one travel lane, but if two lanes are controlled by a Stop on the same approach, confusion can occur as to who has the right of way. If the right lane were channelized and placed under yield control, this could reduce some of that confusion." It would also expand the size of the intersection, and add a crossing for bicyclists. It is not clear that MassHighway would accept funding the addition of a second lane with a four-way stop, because of safety concerns.

Q. What about bicycle and pedestrian safety?

A. The available information and all discussions with many experts in the field indicate that single-lane roundabouts are the safest solution for bicyclists and pedestrians, mainly because the design physically forces all vehicles to slow down (people can't run roundabouts like they can traffic lights or stop signs) so serious accidents are avoided. Though there is limited recent, statistically valid, US data about accident rates for bicycles and pedestrians in roundabouts (reportedly because the rates are so low), European data indicates a significant increase in bicycle and pedestrian safety.

Q. Why not just leave the four-way stop?

A. There is a public safety impact resulting from the congestion at the intersection with a four-way stop (with or without a right-turn lane). In the past, the Edgartown - Vineyard Haven Road and Barnes Road provided better access for emergency vehicles, including access to the Hospital, than the very congested routes along the water (Five Corners, Look Street intersection, etc.). The current delay with a four-way stop - presently averaging 8 minutes and up to 20 minutes in normal conditions in the summer, much longer if the Drawbridge is closed to vehicular traffic - could have serious consequences for an emergency trip.

Four-way stops are appropriate for low-volume intersections, with similar traffic volumes in both directions. MS Transportation recommended against the four-way stop as anything other than an interim solution here, pending implementation of a more suitable permanent solution. According to the leading experts in intersection design in the country, including the staff of the Federal Highway Administration in Washington, there are too few cases of four-way stops being converted to roundabouts to provide statistically valid comparisons of the accident rates, but what information is available indicates that the accident rate for roundabouts is somewhat lower than for a four-way stop.

The stop-and-go traffic and congestion with the four-way stop creates more air pollution and is an inconvenience for users. As traffic volumes increase in the future, these problems will worsen at an exponential rate and will become increasingly intolerable.

Q. Wouldn't relieving congestion at the Blinker make the traffic situation worse at the ends of the Edgartown - Vineyard Haven Road (the Look Street intersection and the Triangle)?

A. Assuming the volume on the road remains the same - and there is no indication that there would be any significant change - it would make no difference to traffic at the ends of the road whether it takes ten seconds or ten minutes to travel through the Blinker intersection. A traffic light would cause the flow to be more uneven, but the considerable distance to the ends of the road would largely smooth this out.

Q. Wouldn't a roundabout negatively impact the adjacent businesses?

A. The only impact would be that customers going to and leaving the business would no longer be held up in congestion and blocked driveways. It is not anticipated that any taking of private property would be required. There are no other anticipated impacts on abutters.

Q. Why spend money on roads instead of alternative means of transportation?

A. Considerable funds are going to alternative modes. The funds for the construction of any project would come from MassHighway and the Federal Highway Administration's annual Transportation Improvement Program (TIP), returning to the Vineyard what we pay in gasoline taxes. Last year, by special agreement, the TIP funded the purchase of buses. This year, it is slated for repaving New York Ave. in Oak Bluffs, including widening the shoulder to better accommodate pedestrians and bikes. Next year's project is to widen sidewalks between Circuit Ave. and Oak Bluffs Harbor. A separate bicycle path is being included in Sengekontacket bridges, the Drawbridge, and the Hospital plan. A subcommittee of the Joint Transportation Committee is working on a plan of bicycle network improvements that will probably translate into many projects to be implemented in coming years.