Thousands of riders who rely on the bus to get around Boston could soon see improvements to their commutes.

Plans were announced this week to upgrade the traffic signal system citywide so that buses are given priority at intersections. The goal is to cut transit delays by boosting the speed and reliability of buses.

After a test of real-time signal priority at three different intersections along Brighton Avenue, a roadway that runs through the Allston neighborhood, found a drop in bus delays from red lights, and thus had faster travel times, Boston and the MBTA said they were collaborating to expand the system.

Transit signal priority works by essentially giving “special treatment” to buses. The locations of buses are tracked and predicted, then used to inform the system in real-time so that signal adjustments can be made. The upgrades will be made to the Traffic Management Center in Boston.

Waiting at red lights causes up to half of transit delays, according to the transit agency. Officials say the tweaks could make significant cuts to that time for bus passengers.

The initiative is part of the T’s Better Bus Project, plans that include updating bus routes, increasing service, enhancing bus stops, and installing dedicated bus lanes. The first phase of its long-awaited network redesign initiative throughout Greater Boston began in December. Buses account for 40 percent of overall ridership across the agency.

Transit advocates have pushed for improvements to the bus system for years.

Makayla Comas, co-executive director of the advocacy group LivableStreets Alliance, welcomed the plan for the new signals as a “great investment,” particularly for areas where dedicated bus lanes may not be the strongest option available, or even viable. The majority of folks who take the bus, which Comas called “the unsung hero of the system,” are low-income, people of color, disabled, and older adults.

“If we are trying to think about, ‘How do we make Boston streets work?’ and ‘How do we make sure that folks who deeply rely on public transportation are able to take it and feel like they want to take it consistently?’ — I think we need to do a deep evaluation of our bus system," she said.

Traffic congestion in Boston is notorious, with drivers often complaining (or rather, blaring their horns) about being stuck bumper-to-bumper, particularly during rush hour. Earlier this month, the city again ranked among the top five most congested cities in the United States and among the worst worldwide, according to an annual study from INRIX, a transportation analytics company.

However, traffic in the city is improving, with the average motorist traversing Boston having spent 79 hours stuck in traffic last year — a 10 percent drop from the year prior, the study found.

Jonathan Gulliver, state highway administrator at the Massachusetts Department of Transportation, said some of the key contributing factors to the smoother traffic flow likely included investments in infrastructure, such as optimized traffic signals and dedicated bus lanes, growing ridership on buses and trains, and more people choosing to walk or bike.

In Boston, a “proof-of-concept” test of the transit priority signal system began in July at three intersections along Brighton Avenue, where two busy bus routes stretching between Union Square and Packard’s Corner are traveled by about 15,000 passengers daily. The city also installed bus-bike priority lanes along that stretch several years ago.

“Traditionally traffic signals have been timed without prioritizing the flow of bus routes,” Mayor Michelle Wu said in a statement. “This is another step to retime signals to keep traffic moving for all road users in our city.”

Separately, the city announced a partnership with Google last summer that officials said would allow it to harness artificial intelligence to tackle congestion head-on and improve traffic flow. The tech giant’s “Project Green Light” team uses AI and Google Maps’s driving trends to model traffic patterns and also make signal timing recommendations for city traffic engineers to implement, according to the company’s website.

At intersections in Boston where the suggested signal timing changes were made, including in Mission Hill and Jamaica Plain, there were quick improvements, officials said at the time, with stop-and-go traffic reduced by more than 50 percent in two spots.

Transportation planners said the use of the technology is just one tool of many but they were hopeful that it would reduce, at least on some scale, preventable traffic snarls.