An idea to improve traffic flow near the heavily congested intersection of Maybank Highway and River Road on Johns Island simply by keeping the light green a little longer sounded too good to be true.

And it was.

Charleston County Council-man Joe Qualey in January pitched the idea of changing the timing of the lights to the city of Charleston, in which the intersection lies.

Hernan Pena, the city’s director of traffic and transportation, doubted from the start that the plan would work.

After he had staffers invest about 70 hours researching it, he sent a letter to Qualey letting him know it had failed.

Traffic snarls at the intersection every evening as vehicles back up onto the bridge over the Stono River.

The problem is so severe that some people call it the “bottleneck bridge.”

Qualey thought changing the timing of the light would allow more traffic from Maybank Highway to pass through the intersection, which would improve the flow.

A similar strategy was effective at the intersection of Folly and Camp roads on James Island on busy beach weekends, Qualey said.

But in his letter to Qualey, Pena said the plan failed to improve the flow of traffic largely because the choke point lies at the foot of the Paul J. Gelegotis Bridge across the Stono River, where two lanes on the bridge narrow to one on Maybank Highway.

That’s about a mile from the intersection.

Qualey said the plan was worth exploring, and it didn’t cost anything.

Pena said clearing the congestion at the intersection of Maybank Highway and River Road will take a larger, more permanent solution.

Molli LeMin, construction project manager for Charleston County, said a $30 million project that will improve the flow of traffic along Maybank Highway from the Stono River bridge to Main Road is in the works.

She estimated the work would be complete around the fall of 2016.

The project will create a “pitchfork” near the intersection, which will provide access roads from Maybank Highway near the bridge to River Road. Because traffic headed to River Road will be diverted before the intersection, congestion there will be reduced.

The project also calls for widening and adding center turn lanes on portions of Maybank Highway, LeMin said.