The left-hand HOV exit ramp where seven people from Ohio lost their lives this month is the only one of six studied on metro Atlanta's freeways where people have been killed in the past nine years. Car occupants in two earlier crashes also died after taking the exit ramp at Northside Drive from I-75.

The state Department of Transportation released Wednesday nine years' worth of crash data for the six exits, through 2006, as well as data on an exit from I-75 to Akers Mill Road, which has only been studied for two years. It did not count crashes at corresponding right-hand exits. An eighth left-hand HOV exit, from I-85 to Lindbergh Drive, was not included in the data, officials said.

Four of the eight left exit ramps go straight, mimicking the direction of the highway, including Northside Drive. Of those four, Northside is the only one where drivers do not see a stoplight ahead. Instead, there are stop signs at the top of the ramp and "stop ahead" signs. On the interstate approaching the ramps, the only indication that keeping left means exiting the freeway comes on signs at the exit itself. At the Northside Drive exit, HOV drivers come upon the exit somewhat suddenly after rounding a curve.

Up to now there has been no stoplight at that exit because the ramp carries only about 500 cars a day, said DOT spokeswoman Crystal Paulk-Buchanan. But under a current DOT review sparked by the bus tragedy, a stoplight there is a possibility, she said.

Ronnie Bell, a Plano, Texas, traffic engineer who runs the federal advisory committee on traffic signals, said federal guidelines do not require traffic signals at left-hand exits or ramps with specific placement. But engineers can decide that a certain level of traffic volume or crashes warrants putting in a signal, said Bell, who emphasized he had not studied the Atlanta site. He also said engineers have to use judgment to make sure a signal wouldn't create problems, such as backing up cars onto a full-speed highway lane.

Two weeks after the bus crash, DOT enlarged the stop- and "stop ahead" signs on the ramp and added other markings lower on the ramp, including the word "EXIT."

On March 2, the driver of a charter bus carrying an Ohio university baseball team apparently mistook the left-hand HOV exit ramp onto Northside Drive for a freeway lane. The bus crashed into the barrier wall on Northside Drive and back onto I-75 below, killing five baseball players, the driver and his wife.

Far and away the most crashes happened at the southern end of the HOV system, at the southbound HOV exit at C.W. Grant Parkway, near the airport. The records show 52 crashes there, with 30 injuries. Paulk-Buchanan said that I-75 in that area had higher traffic volume than the areas around the other ramps.

Drivers approaching that HOV exit have their view of the stoplight at the top obscured for a time by overhead signs.