The US state of California is testing a new traffic control system called "smart highways" that may cause some drivers to be stopped by traffic lights on the ramp for up to four minutes before getting onto the highway. However, the transportation department believes that this will help alleviate congestion on the main line and shorten the overall commuting time.
On the 1st of this month, the Riverside County Transportation Commission opened an approximately 8-mile smart highway pilot section on the northbound section of Interstate 15 in Temecula. According to reports, three local ramps - Temecula Parkway, Rancho California Road and Winchester Road - have been connected to a new ramp signal control system, and algorithms are used to uniformly schedule when vehicles are allowed to enter the main line of traffic.
Unlike traditional ramp signals that use fixed short-period releases, this system dynamically determines the release frequency based on real-time traffic conditions. Therefore, the time a single vehicle waits at the red light may be significantly extended, and some drivers may even have to wait four minutes or more before merging onto the highway. Although the waiting time is significantly longer, traffic officials believe that by "limiting flow" at the entrance, the frequent starting, braking and queuing phenomena on the main line can be alleviated, thereby improving the overall traffic flow efficiency and allowing drivers to spend less time on the entire stretch of road than the traditional ramp signal scheme.
The pilot program will cost about $33 million and is scheduled to run for two years. Riverside County Transportation Commission spokesman David Knudsen said that if the pilot is successful, the system will be rolled out to other road sections in the county and may be deployed to other chokepoint road sections in California in the future. He emphasized that compared to investing heavily in widening lanes, using intelligent control to improve the operating efficiency of the existing road network is a more economically feasible option.
The stretch of highway between Temecula and Murrieta has long been known for congestion: Under ideal conditions without traffic, the trip takes about 10 minutes, but during the afternoon rush hour, drivers often take 25 to 45 minutes to get through. The local government hopes to alleviate the commuting pressure on this "bottleneck" section through more sophisticated ramp management without large-scale road expansion.
In response to external concerns about "potentially dangerous systems controlled by artificial intelligence," Knudsen specifically clarified that this intelligent high-speed system is not driven by artificial intelligence in the general sense. The system relies on advanced sensors laid on the road to monitor traffic speed, flow and other data in real time, and then adjusts according to preset logic, rather than being controlled by AI with autonomous learning and decision-making capabilities. He said that the coordinated control between multiple ramps is to form a smoother and more coherent traffic flow on the main highway.
In fact, smart highways are not the first of their kind in California. As early as 2020, Australia has deployed similar technology on some road sections; many highways such as Interstate 25 in Denver, Colorado, have also introduced related systems. The data published locally is quite eye-catching: on corresponding road sections in Australia, travel time has been shortened by about 35% to 65%; on highway sections in Denver, travel time has been reduced by about 20%.
In the view of supporters, if California's pilot can replicate the improvement effects of Australia and Denver, even if drivers have to wait a few more minutes before the ramp, as long as the overall travel time is significantly shortened, the smart highway will be a "cost-effective" deal. However, in actual operation, how to strike a balance between efficiency improvement and public experience still needs to be answered by this two-year pilot.