Will Riverside Circle work? ‘It can’t get any worse’

Salisbury officials are leaning toward adopting a 120-foot-diameter traffic circle for the Riverside Drive, Carroll Street, Camden Avenue, Fitzwater Street intersection. It would be called Riverside Circle.

The city’s plan to build a traffic circle at the always messy Riverside Drive/Mill Street/Carroll Street/Camden Avenue intersection had its first detailed public airing this week, once again generating both concern and optimism.

The City Council on Monday reviewed the Riverside Traffic Circle Feasibility Study, prepared by city staff with a traffic engineering firm, Wallace Montgomery & Associates. The 26-page report includes an analysis of existing conditions, lists project objectives, reviews future traffic needs and proposes two designs for a huge traffic circle for Salisbury’s busiest intersection.

Any confluence of four major city thoroughfares would certainly create traffic headaches, but the Mill Street area is especially burdened by two other intersections — the Fitzwater Street crossing at West Main Street and the intersection with Route 50 at the Salisbury Parkway.

At several time points each day, traffic flow from cars entering Mill Street from Riverside and Carroll is dictated traffic lights at Route 50 and West Main.

At peak times, it can take several minutes just to proceed through the three blocks. And because the overwhelming majority of drivers in that corridor position themselves to turn left at either West Main or 50, the two traffic lanes are not used to capacity.

The traffic problem is one that has plagued Salisbury since resident construction exploded – and the population boomed – west of the city in the 1980s.

While traffic volumes and signal times are the only remedy for West Main and 50, a traffic circle has long been touted as a solution for Riverside and Carroll.

Engineers conducted their observations of the intersection on Wednesday, March 1 – in the “worst possible circumstances.” They focused on driver behavior, traffic patterns, and roadway geometry.

Two circle options

Engineers have settled on two traffic roundabout options:

  • A 120-foot-diameter circle with a bypass lane for cars headed south to Riverside.
  • A 150-foot-diameter circle that might allow better overall traffic flow but block access up the hill to Camden Avenue.

Meanwhile, the study’s observations would be immediately recognizable to anyone who routinely traverses the corridor:

  • All three signals are coordinated and operate with a 120-second cycle length during both the morning and afternoon peak periods.
  • Queues formed in the both directions along Mill Street for vehicles wishing to turn left during peak periods. Vehicles seem to overuse the right lane in both directions, leaving the center lanes empty.
  • There was significant unsafe weaving present on the bridge all day long, likely due to driver confusion about lane use and hesitation.
  • Vehicles travelling along Mill Street and turning from Route onto Mill Street consistently run red lights and pull into the middle of the intersection to avoid being delayed at the intersection waiting for the next green light.
  • At approximately 8 a.m. that March 1, southbound Mill Street backed up all the way to 50 in the right lane. Vehicles were unable to clear through Main Street at Mill Street.
  • Vehicles used the parking lot in the Northwest quadrant of the Mill Street and Main Street intersection as cut through to bypass the red light along southbound Mill Street.
  • Vehicles approaching from Riverside Drive turn right on red onto Camden Avenue when southbound Mill Street has the green light, with little regard for approaching traffic.
  • During the midday peak period, left turns from eastbound Riverside Drive to northbound Mill Street began to back up through the intersection. Vehicles pulled into the middle of the intersection to avoid being delayed at the intersection waiting for the next green light.
  • The northbound left turn pocket on Mill Street Bridge to Main Street spilled out into adjacent lane blocking through traffic, multiple times throughout the day.
  • Northbound Mill Street left turns onto westbound 50 showed significant hesitation when there was a vehicle approaching from the north. This may be due to the fact that there is a permissive double left-turn movement, and they must yield to oncoming though traffic.

In summary: a traffic engineering mess.

Seeking council input

Council members on Monday discussed problems they currently see with the intersection, but no one weighed in on which size traffic circle should be built. The council approved the conversion to a circle when it adopted the Main Street Master Plan in 2015; construction monies were approved as part of the city’s capital spending plan.

Salisbury resident Henry L. Dibbern Jr., who has lived on McBriety Circle off Riverside Drive since 1988, said he has previously tried to raise his concerns about the circle and understood that there would be time later.

“I’m a little disappointed to hear the decision has already been made on the traffic circle,” he said.

Dibbern said he wasn’t opposed to traffic circles in general, pointing out that “Fruitland’s works quite nicely,” but said he was “worried that we’re committing to something that’s not going to work.”

“My major concern is that the study doesn’t identify one of the major contributing factors to congestion in that intersection – that is drivers entering that intersection from Carroll Street when there’s no opportunity to pass completely through the intersection,” he said. “People using that right-turn signal will fill up from West Main Street on back.

“This is going to create a huge clog.”

The study does comment that because drivers are trying to merge into the left-turn lane, the right lanes aren’t used to enough advantage.

“The problem here is the traffic light at Mill Street. There’s no place for traffic in the circle to discharge to the north.”

Mayor Jake Day repeated that the plan was being presented for information purposes, not approval. “We’re looking for council input,” he said. “It’s a big project and should have council input.”

Addressing concerns about the traffic lights on Mill Street, Day emphasized that the circle decision was made with State Highway Administration support, as state engineers control those signals.

“They will make sure Mill and Main, and Mill and 50, are tied to support that (Riverside Circle) intersection,” he said.

Day also saluted SHA leadership for its cooperation and help.

“Historically, the city has told SHA what it wanted to do and SHA has said ‘no – we want to take a different approach.’ They have been very supportive in terms of enabling this.”

Day said state engineers have insisted the circle “works from a functional standpoint,” which is a main reason for the study and the multilayered decision-making process.

Day also made a point often heard across the community when people talk about the traffic corridor.

“If you read the study,” he said, “I think what it shows is it can’t get worse than it is.”

Day said population growth will add to the woes and the current intersection configuration will make matters worse.

“It will (get worse) in time, but it can’t get worse in terms of its functionality. This is not a great intersection.”

The 120-foot roundabout proposal.

120-foot-diameter roundabout

According to the study, this concept proposes a multi-lane roundabout of 120-foot inscribed diameter with a bypass lane to replace the current signalized intersection. The existing bypass from Mill Street to Riverside Drive would remain in place with modifications to encourage traffic to reduce their speed to approximately 25 to 30 mph.

Vehicles wishing to make any other movement would be directed to use the roundabout. Camden Avenue would remain as a one-way exit. Pedestrians would be accommodated at crossings over Riverside Drive, Camden Avenue and West Carroll Street.

Mill Street would have a single entry lane for through movements to Camden Avenue and West Carroll Street. Riverside Drive would have two entry lanes: the left lane would be for exclusive movements to Mill Street, while the right lane would accommodate all movements.

West Carroll Street would have two entry lanes: the right one would be an exclusive right onto Mill Street, while the left one would permit movements to Riverside Drive and Camden Avenue.

There is potential for conflict at the Camden Avenue exit where vehicles would cross directly in front of the entrance from Riverside Drive. A careful design to encourage entering traffic to wait for vehicles exiting to Camden is required here.

Amanda Pollack, an engineer who serves as the city’s Director of Infrastructure and Development, said officials were leaning their support toward the 120-foot circle.

150-foot-diameter roundabout

This concept proposes a multi-lane roundabout of 150-foot inscribed diameter to replace the current signalized intersection. The Camden Avenue exit would be closed and traffic redirected to Riverside Drive. Pedestrians would be accommodated at crossings over Riverside Drive, Camden Avenue and West Carroll Street.

The roundabout would include striped bypass lanes that would direct traffic within the circumference of the roundabout but restrict any weaving with circulating traffic. The bypass lanes proposed are from Mill Street to Riverside Drive, and from Riverside Drive to West Carroll Street.

Mill Street would have two entry lanes: the left lane would direct traffic making a maneuver onto West Carroll Street, and the right lane would direct traffic into the bypass lane leading to Riverside Drive. Riverside Drive would have three entry lanes.

The middle and left lanes would permit vehicles to traverse the roundabout and onto Mill Street. The rightmost lane would direct traffic onto West Carroll Street through a bypass that would permit vehicles to perform the maneuver without entering the circulatory area of the roundabout. West Carroll Street would have two entry lanes: the left lane would permit a maneuver onto Riverside Drive and Mill Street, and the right lane would exclusively direct vehicles onto  Mill Street.

A big problem in this plan is that Camden Avenue would have to be closed to access.

An exit could not be reasonably accommodated for safety reasons, as there would be a high potential for crashes due to conflicts with the entering lanes from Riverside Drive. Closing this road would divert traffic onto Riverside Drive or West Carroll Street. It is likely that a greater percentage would use Riverside Drive.

The engineers, however, pointed out that closing Camden Avenue may be advantageous for other reasons: It is generally a residential street which currently handles a significant volume of through traffic and closing this road would reduce such traffic, which may be preferred by residents.

Cost estimates and benefit analysis

The proposed concepts were developed to a planning-stage level of detail that includes major quantities such as paving, grading, curb and gutter, pavement markings and preliminary signage costs.

Estimates are the 120-foot circle would cost $859,400, when right-of-way purchases are included.

The 150-foot- circle would require more construction and the acquisition of more right-of-way space, and cost about $1.09 million.

Engineers recognized that any traffic circle will not be a cure-all for the corridor’s traffic woes, but maintained a roundabout would “provide for an improvement in community value.”

“Aspects such as community value can be inferred from changes to the vehicular level of service, green space, and non-automobile accommodations,” the report said. “In general, community value is enhanced by improvements that reduce vehicular speed and delay, provide space for landscaping or planting, and improve local residents’ ability to move around their neighborhood.”

The report also ranked a circle far ahead of the current intersection setup.

“The proposed concepts all exhibit properties which make them desirable,” the report said. “The traditional improvements would retain the existing intersection configuration that local residents and commuters are familiar with, involve minimal disruption to traffic, and have minimal impacts to surrounding properties.

“The roundabouts on the other hand would offer improved levels of service in future years in addition to improving conditions at the intersection for both pedestrians and cyclists.”

 

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