To improve air quality, Berkeley considers saying ‘no’ to 4-way stops at intersections

Berkeley is considering converting all intersections with 4-way stops to just 2-way stops, the first step in eliminating stop signs altogether.

Update, April 2: As many of you surmised, this was an April Fools’ Day story.

Original story: The Traffic Management Study Group, a subcommittee of the Transportation and Traffic Commission, issued their first interim report at a special subcommittee meeting late Friday afternoon. The report recommends phasing out all 4-way stop signs throughout the city. Citing carbon footprint from 4-way stops as the primary reason, the report calls for replacing nearly all of Berkeley’s 4-way stop signs with 2-way stops and eventually transitioning most intersections to “smart” traffic signals.

“Each 4-way stop intersection releases as much carbon into the environment as a 737 taxiing from Gate 2 to Gate 31 at Oakland airport,” the report states. Recognizing that the transition could be “problematic” at some intersections, the subcommittee report recommends a new design for the new 2-way stop signs that alerts drivers accustomed to 4-way traffic control.

The report also calls for a long-term strategy to replace most of the stop signs in Berkeley with “smart” traffic signals by 2026.


These recommendations come in advance of anticipated state legislation, SB-409, that will preempt local public works and traffic management departments, replacing local control of intersection design with state-wide requirements.

“This is a necessary component of California’s strategy for meeting our greenhouse gas reduction goals,” Eileen Write, a state representative from the Los Angeles area, explained to the few members of the public who found out about the subcommittee meeting. “Local jurisdictions, to put it bluntly, have failed to reduce these sources of pollution. As a result, we are now facing a state-wide 4-way stop sign crisis, and have to deal with all the slow traffic flow and avoidable air pollution that come with it.”

Each intersection converted from 4-way to 2-way stops will reduce atmospheric carbon emissions equivalent to up to 200 square feet of solar panels.

Despite this explanation, the mood in the room was strongly against giving up local control of intersection design, and several commissioners advocated calls and emails to the state legislature to oppose the new bill.

“We do have a traffic crisis, and state-wide action is called for,” insisted Marin County traffic engineer Waldo Graide, who had been brought in as a consultant to the subcommittee. “Analog stop signs are extremely dumb devices. They cannot respond to demand, they cannot detect oncoming traffic, and they cannot alert repair crews when they are damaged.”

But for the short term, according to the subcommittee report, 4-way to 2-way conversion will keep tons of greenhouse gas out of the environment and speed up traffic flow. As per the report, the long-term plan is to convert all intersections that currently have 4-way stop signs to smart signals, which will make the intersections even cleaner and even more efficient. The smart signals will detect oncoming cars and turn red or green to optimize traffic flow, minimizing high-polluting engine idle time, braking and accelerating.

“Won’t this lead to speeding on the arterial streets?” shouted a woman who identified herself only as a Cedar Street resident.

Driver survey results. The survey was conducted while cars were stopped at 4-way intersections.

“No, not after we transition to smart signals,” Graide replied. “They detect the speed of oncoming cars and turn red for any car approaching at a speed greater than the 25 mph limit. Furthermore, license plate cameras built into the new signals will catch anyone who runs the light. It will calm traffic and also be a great source of revenue.”


Commissioner Carmen Gia expressed her support for the concept. “Instead of cars racing from one 4-way to the next, wasting fuel, time and engine wear with all the stops and starts, we can look forward to stately, constant-speed, energy-efficient cruising through our residential neighborhoods, always at safe speeds.”

“Does this mean we can also phase out speed bumps?” asked Milvia Street resident Jocelyn Shaik.

“Not at all, we still need them for the long blocks between signals,” said Gia. “In fact, the plan calls for adding 1,387 new smart speed bumps. These remain flush with the road surface most of the time, so you won’t even know they are there if you approach at a reasonable speed. But the smart speed bumps use the same technology as the smart traffic signals to detect the speed of an approaching vehicle. If a car is approaching a speed bump faster than the recommended limit, the bump will pop up, just for that car. This will reduce wasteful braking and accelerating, save time, and keep speeds appropriately slow in the neighborhoods.”

According to the report, the speed bump design was developed with funding from CABAM, the California Association of Brake and Alignment Mechanics.

The report also notes that emergency vehicles will transmit a code to keep all the speed bumps down and give themselves priority at intersections, similar to the system that currently gives Rapid buses priority. Police cars will even be able to make all the speed bumps pop up extra high when they are in hot pursuit of a suspect.

“Looking to the future, smart traffic controls will help make our streets self-driving ready,” the report concludes. “This is the new paradigm for traffic control. Instead of the one-to-many topology of information flow from an intersection signal to the vehicles, the new system responds to traffic data. As vehicle autonomy evolves further, the cars will communicate with one another digitally and negotiate the optimum flow peer-to-peer, then relay the instructions to the traffic signal.”


“If a car is approaching a speed bump faster than the recommended limit, the bump will pop up, just for that car. This will reduce wasteful braking and accelerating, save time, and keep speeds appropriately slow in the neighborhoods.”

Hans Freeride and Hap Hazard, developers of autonomous vehicle software, made a brief presentation. They described another feature that Berkeley drivers can look forward to in the near future. “With peer-to-peer traffic optimization, traffic control can move beyond purely objective considerations. Each driver can explain verbally to their networked driving computer why their trip is particularly important and time-sensitive, and the most compelling narrative will get priority at the intersection.”

“This is disturbing,” complained one driver. “This is discrimination. Traffic signaling should be an arms-length transaction, based purely on traffic flow.”

But the consensus among city officials was that subjective considerations have always been part of intersection right-of-way. “Just look at Boston,” noted Charles River, one of the subcommittee members.

“The AI software controlling the traffic signal,” added Graide, “has every right to make value judgments concerning who gets the green light.”

The subcommittee report calls for improved shark attack warnings in Brazil and Australia.

When questioned about the high cost of installing signals at every intersection, City Budget Director Roxanne Scholes acknowledged that signals are expensive. “Each intersection will cost as much as 0.15 units of new affordable housing subsidy,” she said. “But this is temporary, so it lends itself to bond funding. By 2030, when a heads-up data display will be required in every car, we can do away with physical traffic signals entirely. Traffic lights, stop signs, street signs, and even most lane markings will be artifacts of the past, allowing huge cost savings. All the info a human driver needs will be displayed on the windscreen. Autonomous vehicles won’t even need that. We will finally be freed from the visual blight of signs, traffic signals and stripes on the roads, and I’ll be able to floss my teeth on the way to work.”

In answer to a question about how pedestrians will interface with the proposed smart signals and peer-to-peer optimization, Freeride explained that if their software is implemented, pedestrians equipped with wearable VR devices and position transponders will have no problem. “They will see all the traffic, and all the traffic will see them. Even around blind corners. It’s much more reliable than video pattern recognition.”

Hazard anticipated the next question: “These devices will be paid for via micropayments every time they are used to cross the street. Admittedly this does incur a small expense for pedestrian transit mode, but we think it’s a small price to pay for pedestrian safety and for saving the planet.”

“How do the smart signals handle bicycles?” asked East Bay Bikes representative Rick Shaw.

“We all know that stop signs and traffic signals are irrelevant to bicycles,” answered Commissioner Lisa Mercedes. “However, after consultation with numerous bike advocacy organizations, the specification for vehicle detection and routing was modified so that the smart signals will at least try to detect bicycles. In most cases the lights will give them right-of-way at controlled intersections.

“Our AI software is so good,” added Hazard, “that it is either oblivious to bicycles, or it is aggressive, just like a human driver.”

“But bicycles still have the moral high ground,” argued transit advocate Doris Cloesing. “They are part of the global climate solution, not the problem, so the smart signals will give bikes priority regardless of approach speed. That is, except when the software fails to detect them.”

The meeting was adjourned on schedule.