{"id":24335,"date":"2023-02-16T15:08:38","date_gmt":"2023-02-16T14:08:38","guid":{"rendered":"https:\/\/www.sciencefocus.com\/?p=137355"},"modified":"2023-02-16T15:35:33","modified_gmt":"2023-02-16T14:35:33","slug":"we-need-fourth-white-traffic-light-to-ease-road-congestion-science-says","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcsciencefocus\/rss_feed\/we-need-fourth-white-traffic-light-to-ease-road-congestion-science-says\/","title":{"rendered":"We need fourth \u2018white\u2019 traffic light to ease road congestion, science says"},"content":{"rendered":"

The system would allow autonomous vehicles to control the traffic flow at busy intersections. <\/p>

By Jason Goodyer\n \t\t<\/p>

Published: Thursday, 16 February 2023 at 12:00 am<\/p>

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Adding an additional white light to traffic lights could enable autonomous vehicles (AVs) to control traffic flow and improve travel time<\/a>, computer simulations run by engineers from North Carolina State University have found.<\/p>\n

Under normal circumstances, the proposed four-light system operates in the same way as current systems three-light systems \u2013 red means stop and green means go etc. However, if a threshold number of self-driving cars are detected approaching an intersection the white light phase is triggered, overriding the three-light system.<\/p>\n

This signals to human drivers that self-driving cars have taken control of the traffic flow and are coordinating their movements via wireless communication. Any cars being driven by a human are then simply required to follow the car in front \u2013 if the car in front stops, they stop; if the car in front goes through the intersection, so do they.<\/p>\n

\u201cThis concept we\u2019re proposing for traffic intersections, which we call a \u2018white phase,\u2019 taps into the computing power of AVs themselves,\u201d said co-researcher Dr Ali Hajbabaie<\/a>, an associate professor of civil, construction and environmental engineering at NC State.<\/p>\n

\u201cGranting some of the traffic flow control to the AVs is a relatively new idea, called the mobile control paradigm.<\/p>\n

\u201cIt can be used to coordinate traffic in any scenario involving AVs. But we think it is important to incorporate the white light concept at intersections because it tells human drivers what\u2019s going on, so that they know what they are supposed to do as they approach the intersection.<\/p>\n

\u201cAnd, just to be clear, the colour of the \u2018white light\u2019 doesn\u2019t matter. What\u2019s important is that there be a signal that is clearly identifiable by drivers.\u201d<\/p>\n

The simulations found that small improvements in traffic flow occurred when as little as 10 per cent of the vehicles at an intersection were autonomous. And as the percentage of AVs increased so too did the traffic flow.<\/p>\n

\u201cEven if only 10 per cent of the vehicles at a white phase intersection are autonomous, you still see fewer delays,\u201d said Hajbabaie.<\/p>\n

\u201cFor example, when 10 per cent of vehicles are autonomous, you see delays reduced by 3 per cent. When 30 per cent of vehicles are autonomous, delays are reduced by 10.7 per cent.\u201d<\/p>\n

Although AVs are not ready to adopt the new approach in the immediate future, it would be relatively straightforward to implement with only minor modifications to intersections and AV software updates, the researchers say.<\/p>\n