ITHACA, N.Y. – Ithacans have varied strategies for getting through the so-called “Five Corners” intersection where Route 366, Dryden Road, Maple and Oak Avenues and Cornell Street converge. Some drivers wait patiently behind the stop line for the nearly minute-long signal cycle while others gun it and run it. Some creep up over the crest of the hill to try to glimpse competing traffic, while others wade blindly into the tangle and hope for the best. Pedestrians sometimes take each spur one at a time, but sometimes dash straight across the middle, and meanwhile cyclists are left to interpret turn signals that could refer to several different paths.
“It’s one of my least favorite intersections in the city,” said Eric Hathaway, city transportation engineer, at a community meeting about redesigning it on Thursday, March 21.
Hathaway and representatives from C&S, an engineering firm the city has contracted to consult on the redesign, said an overhaul of the intersection is urgent. Already, its crash rate is more than double the statewide average according to Kelsey Wessel, lead engineer on the project with C&S. Between 2013 and 2017 there were 20 collisions in the intersection, she said.
As the number of students living in the area increases, problems are only going to worsen.
Hathaway and C&S presented two possible design solutions. The first would upgrade traffic signals and improve road grading, offering modest safety and efficiency gains at relatively low upfront costs. The second would replace the existing intersection with a roundabout, requiring costly upfront construction but offering significant long-term benefits.
The Office of Engineering is seeking public input before moving forward with either proposal. Here are the details you need to weigh in.
Upgrading traffic signals
The traffic signals at Five Corners are woefully out of date, Hathaway said at Thursday’s forum. They cannot detect when a vehicle approaches, so drivers, cyclists and pedestrians stopped at a red light need to wait a full cycle whether or not there’s traffic coming from other directions. That delay worsens traffic backups and can lead to noncompliance when people grow impatient.
Wessel said upgrading the signal equipment and configuration could improve efficiency and safety while reducing maintenance costs from aging lights. Adding vehicle detection and installing pedestrian-activated crossing signals would reduce wait times and perhaps improve compliance as a result, which would prevent accidents caused by drivers or pedestrians crossing out of turn.
The city could also reconstruct a portion of the intersection to reduce the vertical grade alongside upgrading signals, to improve visibility for cars entering from Route 366 in particular.
C&S estimates the cost of upgrading traffic signals would be about $360,000, and adjusting the grade at the same time would bring the cost to $500,000. While that is a lower figure than the cost of creating a roundabout, Wessel said the improvements would also be more modest.
She played a simulation demonstrating how vehicle and pedestrian traffic would flow through the intersection in 2029, with traffic volumes adjusted for a local population increase and signal timing optimized. On the screen, cars sat waiting in a line down Dryden Road and Route 366 while pedestrians waited at the corner. Wessel said no amount of signal optimization can eliminate traffic backups during peak hours.
Meanwhile, while Hathaway and Wessel said upgraded signals would improve safety, they pointed out that several current hazards would persist. There are 32 conflict points in a typical four-way intersection, Wessel said, where traffic paths cross and make collisions more likely. In a complex intersection like Five Corners, there are even more opportunities for collisions. Better orchestrating traffic with updated signals might help drivers make better decisions, but it will not eliminate conflict points.
Creating a roundabout
Transforming Five Corners into a roundabout would be a large undertaking. Todd Humphrey, highway department manager at C&S, said construction would likely take four to six months, and the firm estimated upfront costs at about $700,000. According to Hathaway and the C&S team, however, the design has significant advantages over a signal upgrade.
Roundabouts are designed to reduce traffic speeds. Roads would be narrowed as vehicles funnel into the circle, making it feel tight so that drivers automatically slow to about 15 mph, Wessel said.
For that reason, roundabouts are recommended as a component of Vision Zero, a strategy the City of Ithaca recently embraced to reduce traffic related injuries and fatalities.
“When people are at lower speeds, even if they have more decisions to make they make better decisions,” Hathaway said, adding, “When people are going slower and they do make a mistake, it’s less costly.”
If a roundabout were created at Five Corners, there would be no traffic signals or stop signs; vehicles would be expected to yield to traffic before entering the circle and to yield to pedestrians when exiting the circle.
Likewise, pedestrian crossings would not be signalized. While Hathaway said the city could consider adding flashing lights, known as “rectangular rapid flash beacons,” to alert drivers to pedestrians, generally people crossing on foot would simply wait for a gap in traffic before proceeding.
The proposed roundabout design would add small medians, known as splitter islands, on each incoming road. These islands slow traffic and shorten crosswalk distances so pedestrians are exposed to oncoming traffic for less time.
Hathaway responded to concerns about how drivers, cyclists and pedestrians would coordinate their movements in lieu of signals. “Is it just going to become a mess where everyone is waiting? Generally the answer is no,” he said. He cited traffic studies in Minnesota and Portland, Oregon that have shown shorter pedestrian delays where roundabouts are used as well as fewer serious collisions.
Wessel said there are just eight conflict points in a single lane roundabout, and that compared to traditional intersections, research has shown they reduce serious injury crashes by nearly 80 percent.
She pressed play on the same 2029 simulation with the proposed roundabout in place. Traffic moved freely, with no more than a few cars yielding at once, as pedestrians made their way from corner to corner.
Seeking public input
Humphrey joked at the meeting that C&S doesn’t have a stake in which design the city moves forward with: “We get paid either way.” He said in his professional opinion, though, the roundabout redesign offers a better long-term solution. In addition to improving traffic efficiency and safety, he said C&S models show the roundabout would reduce greenhouse gas emissions by allowing vehicles to yield rather than stop. Since the roundabout would require completely reconstructing the affected roadways, it would also reduce road repair costs in the area for the next 20 to 30 years, he said.
But while C&S has a preferred design, the Office of Engineering wants input from the community before moving forward with either proposal.
Hathaway acknowledged that roundabout construction would have negative impacts for local residents and commuters. “That’s the biggest negative to me about the roundabout – detours are not easy in this area, and it takes a while to make a roundabout like this. It’s not as simple as a signal,” he said.
In addition to weighing in on which of the design proposals the city should choose, residents can offer suggestions about how the city could mitigate construction impacts related to either project or could suggest adjustments to either proposal to meet local needs.
Comments can be sent to Eric Hathaway at firstname.lastname@example.org.