For drivers cruising through Palo Alto, the city's efforts to control traffic are impossible to miss.
From new roundabouts and traffic islands to freshly minted bike lanes and curb extensions, the city's push to create "complete streets" for all types of commuting has been proceeding full speed ahead, often to the consternation of construction-weary neighbors.
But while these streetscape projects are all the rage — at times, literally — a slew of more low-key and high-tech solutions also are being used by the city to alleviate the area's traffic woes. These include installing "adaptive" traffic signals that adjust their lights based on real-time traffic conditions; "feedback" signs that flash at speeding drivers and generate speed-compliance reports; and electronic boxes that rely on Bluetooth-enabled devices such as smartphones to gather data on congestion.
This lattermost effort, using Velocity monitors designed by the firm Iteris, are part of Palo Alto's broader effort to better collect, analyze and display traffic data. Santa Clara County has already installed monitors at four area intersections (along Oregon Expressway, Foothill Expressway and Alma Street), and Palo Alto plans to install them at 10 city intersections.
When a Velocity monitor picks up a Bluetooth signal from a smartphone, it will assign a random identification number to the phone so that when the phone passes another monitor, the system can calculate the driver's travel time. If the driver makes the same trip the next day, the smartphone will receive a new identification number, ensuring anonymity. The only data that gets stored is the travel time between one monitor and another, Chief Transportation Official Joshuah Mello told the Weekly.
Mello sees the Velocity devices — as well as other data-gathering technology — as a tool for making Palo Alto's traffic data both more accurate and more publicly accessible. Today, the act of conducting a traffic survey is "more an art than a science," Mello said. People (usually consultants) do their best to count all the cars passing along a busy segment. The Bluetooth monitors, he said, will give the city "a more automated way to monitor whether our arterials are functioning the way they are supposed to."
Other technologies are more conspicuous, even if some of their new functions aren't immediately apparent. Palo Alto since 2003 has been using electronic speed feedback signs — radar devices that display the speed of passing vehicles and, when needed, urge them to "SLOW DOWN" in rapidly flashing red letters. In recent months, however, the city has updated, repaired and reprogrammed all 15 devices (including six that had been inoperable) and installed two new ones, according to the 2017 Traffic Safety and Operations Report, a newly released overview of Palo Alto's various traffic-management projects.
The feedback signs are now stationed along busy stretches of Alma Street, Arastradero, Embarcadero and Middlefield roads, as well as along other prominent arteries. And they are, in many ways, a sign of the times in that they both give drivers a cue to slow down and provide the city reams of data about traffic conditions. The new report notes that the electronic feedback signs have a "traffic-analyzer feature that collects day, time and speed of vehicles and generates charts and speed compliance reports."
So far, the city hasn't been using the data gathered by these signs. But Mello said he'd like to see the city get to a place where it could just pick a road segment and look at all the data collected there without the need for a consultant conducting "snapshot in time" counts that may or may not represent the average day.
Ultimately, Mello said, he'd like to see the city create an online "dashboard" for its street network, with publicly available data showing the performance of various intersections and road segments.
"We're moving toward a place where we're going to have a lot more transparency around data and a better way to visualize the data," Mello said. "That's part of what the project is about."
While a dashboard is a long-term objective, the new technology has a more near-term and practical aim: ensuring smooth and safe traffic flow. The challenge is hard to overstate. The most recent National Citizens Survey showed only 33 percent of Palo Alto's respondents giving the city a high grade (either "excellent" or "good") in 2017, well below the 45 percent who did so in 2007.
To help whisk traffic along, Palo Alto is preparing to expand its use of SynchroGreen, an adaptive system that tracks real-time traffic conditions and modifies signals accordingly. SynchroGreen made its debut on Sand Hill Road in 2015 and was implemented last year on four intersections along San Antonio Road, as well as on East Charleston Road and Fabian Way.
In the coming months, the city plans to bring the adaptive system to Charleston-Arastradero Road, which is also set to undergo a redesign as part of a multi-phase effort launched 15 years ago. The adoption of SynchroGreen on Charleston-Arastradero was one of the conditions that the city included in its environmental analysis for the ambitious streetscape project.
The SynchroGreen system identifies "platoons" of cars that move along the corridor and looks for gaps between these platoons, Mello said. It then strategically serves side streets during these gaps.
For example, if westbound drivers on Sand Hill Road are waiting to turn left onto Stanford's Stock Farm Road and the system detects a gap in traffic heading east on Sand Hill, the system will take advantage of the gap and serve the left-turning cars onto Stock Farm as quickly as possible, Mello said.
The system does, however, has one drawback: It often requires cars to wait longer on side streets.
"We've had some emails and phone calls after we implemented SynchroGreen on San Antonio Road, and some of these were concerns about increased wait times to get on San Antonio. We're making tweaks to address those."
Like most bits of Palo Alto's recently installed technology, the new traffic signals were designed to be compatible with the future dashboard. The Traffic Safety and Operations Report cites the emergence of "intelligent transportation systems" with the capability to monitor, evaluate and modify intersection signal-timing parameters using a very detailed data collection and evaluation of detailed metrics."
Unlike the traditional method, which relies on traffic-simulation models, the new system provides signal-timing recommendations based on actual intersection performance, the report states.
Palo Alto is now moving toward adopting such a system. In 2015, when traffic signals citywide were upgraded, the city's central management system was made compatible with the various data-analysis programs, the report states. The same holds true for most other new devices, Mello said.
"Every time we add something new or look at a new device or system, we're ensuring that an API (application programming interface) be made available that would enable us to link the systems together," he said.