Complicated system helps you drive through Roseville
In an office in the city’s engineering division, frightening video footage displayed on a large monitor shows Roseville being assaulted by oversized insects.
“We’re under attack from giant hornets,” joked Jason Shykowski, senior civil engineer of traffic operations in the city’s Public Works department.
He pointed to a large wasp climbing across one of the screens in Roseville’s Traffic Operations Center. There’s really no attack — but the staff in the office joke about magnified hornets that sometimes clutter the screens intended to show footage of cars traveling along the city’s roadways.
Each of Roseville’s 166 traffic signals has a traffic camera — they don’t call them “surveillance cameras” because this makes people uneasy, Shykowski said, and the devices don’t have the ability to record.
There are 15 screens mounted to the wall in the center, monitored to ensure that traffic runs smoothly. There isn’t one person devoted to staring at the screens all day, as staff shares in the duty.
“So we automate the system as much as we can,” Shykowski said.
Roseville is the only city in Placer County to use what’s known as active traffic management, Shykowski said. But his staff hopes to soon implement a more evolved system that is “traffic adaptive.”
“The goal is keeping vehicles moving on Roseville’s roadways,” said Public Works Director Rhon Herndon.
How the system works
Roseville uses Intelligent Transportation Systems to improve traffic flow. By using signal controllers and traffic cameras, engineers monitor real-time conditions, modify traffic signals as needed and alert motorists to roadway problems, such as street closures or detours.
Say heavy congestion occurs on Douglas Boulevard following a vehicle collision. Each traffic signal controller has a little computer programmed remotely to change signal timing when an incident occurs. Roseville’s system can also be used to alert motorists to avoid the area via changeable message signs.
The city has seven of these signs. Residents can also sign up for e-mail alerts or check out roadway conditions through the Traveler Information website.
Roseville uses traffic signal coordination, which is a method of timing traffic signals along a major roadway to provide for a smooth flow of traffic with minimal stops. The goal is to get the greatest number of cars through a group of coordinated traffic signals with the fewest number of stops.
Traffic signals along a main corridor are synchronized so that cars receive a green light before arriving at the signal. This “green wave” helps reduce congestion and stop-and-go traffic, which results in fewer greenhouse gas emissions.
All of the city’s traffic signals are timed and 87 are coordinated. To coordinate the lights, engineers rely on 70 miles of underground fiber optic and copper wires connecting all the city’s traffic signals. These signals collect vehicle count data. Engineers plug these numbers into a traffic software program to best determine timing.
The length of a cycle on a major roadway varies from 60 to 120 seconds. Engineers program the signals to change as traffic patterns shift throughout the day. For instance, traffic on Galleria Boulevard going to the Westfield mall increases during the evening when people go shopping. Some signals are altered during lunchtime to accommodate an increase in congestion.
“A lot of people eat out in Roseville,” Shykowski said.
High traffic peaks often happen before and after school when parents drop their kids off. This also changes pedestrian patterns so some crosswalks are programmed to allow more time for people to cross the street safely.
Traffic signals are synchronized from 7 a.m. to 8 p.m. on weekdays and 10 a.m. to 8 p.m. on weekends said, Tito Zamora, Traffic Operations Center coordinator. The rest of the time is traffic-activated “first-come, first-served.”
Since implementing the traffic signal coordination system in March 2010, Roseville has seen a 20 percent reduction in travel times, Herndon said.
“People don’t like to be delayed,” he said. “So it’s a convenience.”
But the system isn’t a perfect science and some residents don’t find Roseville streets easy to get around in a timely manner. Resident Lyn Greenhill said while some roadways have improved through the years, some are worse, despite the synchronized system.
“Douglas is a classic example,” said Greenhill, an engineer. “You think everything is good. Then you drive down Douglas.”
He also says the city should take care of unnecessary “little nuisances,” such as the signal on Sunrise Boulevard in front of the Roseville Automall.
“I get stopped there every time,” he said. “It should be that when you leave Eureka or Lead Hill, you don’t stop there.”
Looking toward the future
Roseville’s Traffic Operations Center is costing about $14 million over 20 years. The system, paid for by new development through traffic mitigation fees and $4.7 million in federal grant funding, has proved effective, Herndon said.
“We use a system for calculating level of service that measures the amount of delay at an intersection, that’s like a report card,” he said.
A city policy requires 70 percent of all signaled intersections be at least a level C — considered good — during evening peak hours. Herndon said that more than 90 percent of Roseville’s intersections are C or better. The most congested intersection in Roseville, Sunrise Avenue and Cirby Way, is a level F, because it typically takes a driver more than one signal to get through the intersection.
Now the city wants to go to the next level of traffic coordination — adaptive traffic signals. Staff will present the proposal to Roseville City Council later this year.
Adaptive traffic signals, at a price tag of $12,000 per intersection, self-adjust the timing of traffic signals along a coordinated corridor depending on how busy the roadway is at any given time.
As for Greenhill, he’d like to see a committee of staff and citizens formed to offer input as the city moves forward.
Sena Christian can be reached at firstname.lastname@example.org. Follow her on Twitter at SenaC_RsvPT.