For months now, downtown drivers have been seeing red — a lot of red.
Mostly on traffic signals.
They wait; they count; they think that it wasn't always this way.
Last year the city of Charleston revamped its entire traffic signal system, a complex grid of lights across the peninsula, West Ashley and James Island that is meant to keep traffic moving quickly, efficiently, safely. To a great extent, it works. If you get into the right band of traffic, you can sail down Savannah Highway without hitting a light. Well, except maybe at Wappoo. You can fly, relatively so, on Calhoun Street.
But there were winners and losers here. The losers — of some time — were folks driving north and south on the peninsula.
If you are driving on King,
Rutledge, East Bay and, to an extent, Meeting Street — the major north-south roads — you will get one minute of red light for every 30 seconds of green light at the major intersections. That varies some depending on the time of day, but that's pretty much it.
Meanwhile, east-west routes such as Calhoun and Broad streets see a minute of green for every 30 seconds of red. You can drive the length of Calhoun — 1.6 miles between Courtenay and the Aquarium — in under six minutes. Driving that far on King, Rutledge, Meeting or East Bay will take 10 to 12 minutes, according to a day's worth of driving those routes.
Part of what residents are noticing is a change in the traffic signal cycle. Hernan Pena, the city's Department of Transportation director, says that after years of study, the traffic in the city demanded a change in the cycle of a traffic signal from 70 seconds to 90 seconds to keep the volume of cars we have moving.
That means a traffic light that had gone through its entire range of settings in a little over a minute now takes a minute and a half. At the pressure-point intersections, that extra time has gone to moving east-west traffic.
Pena says that is the way it has to be to avoid traffic chaos. Calhoun Street sees nearly 20,000 cars a day, King maybe gets 11,000 — who do you think gets priority?
To figure all this out, the city's traffic engineers dispatched folks to every intersection in the city over the course of several months to count traffic at every time of day, from 5:30 a.m. to midnight.
In traffic control central, a room in the Greenberg building with a lighted map of every signal in town, Pena has maps that tell you everything you want to know about traffic. He can tell you how many people traveling south on Savannah Highway turn onto Magnolia during the 6 a.m. hour (nearly 200, oddly enough).
All this information goes into computer programs that help design patterns that keep traffic moving so well that you can get across Calhoun with a pause for the cause at King.
You can see them sailing by when you're sitting at a red light on Rutledge.
Right now, consultants are doing an after-study to check their results. Engineers are out driving some of these routes, comparing today's times with the old ways. There may be some tweaks in the fall, but Pena doesn't anticipate much. You change one thing and it sets off a chain reaction. Traffic is about rhythm, and right now the beat is moving east and west on the peninsula.
When the traffic department made Rutledge a two-way street below Calhoun a couple of months ago, they said it was partially done to slow traffic in the area — a patch of road that sees 4,800 cars a day.
Perhaps those people weren't really speeding, they were just trying to make up for lost time.
Reach Brian Hicks at firstname.lastname@example.org or 937-5561.