Rose Crenca, president of the Montgomery County Council, raised questions about the status of a traffic study commissioned by the Silver Spring Takoma Traffic Coalition {Letters to the Weekly, Oct. 15}. To set the record straight, the coalition paid John Erdman, a traffic engineer from Baltimore, $2,500 to investigate the impact of large proposed increases in development on the already congested Silver Spring roads.

The members of the traffic coalition spent this money because they believed the county's department of transportation was doing a very biased job of looking at the traffic impact of County Executive Sidney Kramer's plan to increase jobs in Silver Spring by almost 50 percent. Their suspicions were proved correct by the results of this independent review of DOT's data.

The report was not released to the public because the traffic engineer agreed to do the study only if it was for private use, to help coalition members prepare their testimony for the county council hearings. The engineer was unwilling to release a report on which he might be cross-examined in court, without spending much more time (and a great deal more money!) studying every street in Silver Spring and vicinity.

On Oct. 1, at the county council's first work session on Silver Spring, Mr. Erdman himself explained to all the members of the council that the conclusions of his report supported the coalition's contentions that the county was overestimating the additional traffic capacity on Silver Spring's roads and that transportation management proposals were unrealistic. He also stated the reasons he had not made the report public.

Since Rose Crenca's letter, Mr. Erdman has agreed to release his report to anyone who would like a copy, and copies have been provided to all county council members.

In addition to hiring a traffic engineer, the traffic coalition paid for the services of an attorney, Roger Titus, to testify on legal issues before the council and be available to answer any legal questions the council might have with regard to our position.

Norman Christeller, chairman of the planning board, recently said that the coalition's testimony was some of the finest citizens' work he had seen in 20 years. Rose Crenca wrote in a letter to the traffic coalition's president: "There was a great deal of very thoughtful and valuable testimony at the hearing. I commend you and your colleagues for doing your homework!"

From the beginning, citizens have made a concerted effort to analyze the facts of proposals for Silver Spring, and I think we have done a very credible job at this with the help of our able traffic engineer and attorney.

MICHAEL Z. GRAVITZ Board Member, Silver Spring Takoma Traffic Coalition Silver Spring