A New Canaan developer's revised plan to build houses on vacant property on Chatham Road, denied by the Town Plan and Zoning Commission last August, was rejected again Tuesday night.

The commission voted 7-0 against 50 Development LLC's plan to build three houses on nearly an acre of land at 50 Chatham Road, where a single-family house was destroyed by arson in September 2011. The LLC, which lists Arnold M. Karp of Canoe Hill Road in New Canaan as its principal on the Secretary of the State's website, bought the property for $325,000 on Jan. 31, 2012.

Town Planning Director Joseph Devonshuk Jr. said each of the three lots would exceed the minimum required lot size of 14,000 square feet in the R-2 zone.

Seth Baratz, vice chairman of the TPZ, said the developer had responded to earlier objections to the development by moving a stormwater retention system outside of the property's "square," and Baratz said a report submitted by the developer showed post-development runoff from the property would be less than it is now. The developer also would not do any blasting, which had been a concern of neighborhood opponents, Baratz said.

The developer also had moved driveways to increase "sight lines" for motorists and added turnarounds to the driveways so motorists would not have to back into the street.

But Baratz said he remained concerned about the sight lines from the proposed driveways and said he wasn't sure the sight lines would be adequate at a 10 percent grade. "Our concerns are whether the driveways are safe," he said. "It's not clear to me that [the revised application] meets the sight lines."

Commission member Douglas Soutar agreed. "Whether it meets all of our requirements, I still don't know. It's a close question," he said.

James Kennelly, a commission member, said sight lines were the principal problem for the commission. "What we are responsible for is to ensure this is an absolutely safe site," he said. "I tend to feel I would error here on the side of safety. It strikes me there is some ambiguity here regarding what is a key element."

The traffic report for the project says the stopping distance on Chatham Road required by the town and state Department of Transportation is 155 feet, and that each driveway's sight distance meets that requirement. However the report has conflicting information about how fast a car would have to be traveling to meet that stopping distance, with one part saying 25 mph, which is the speed limit on Chatham Road, and another part saying 22 mph, which is the rate that 85 percent of cars travel on the road.

The traffic report also has conflicting information about the grade of the road for that stopping distance, with one part saying level and another saying 10 percent.