L. Britt Snider took the State of Maryland to task for his "Beach Traffic Blues" {letters, June 9}. Assuming Mr. Snider represents hundreds of thousands of other weekend shore-bound travelers, we obviously need to let people know what is really being done to improve the traveler's situation.

First, thanks to the State of Maryland, and only after a difficult struggle, the U.S. Coast Guard several years ago cut by more than half the number of summer weekend openings at the Kent Narrows Bridge. The Coast Guard refused to cut out all such opening as the state had requested, and it, and not the state, controls the drawbridge schedule. Because the waterway preceded the highway, the Coast Guard requires the state to accommodate boaters' needs.

Second, the state is building bridges and interchanges along U.S. Route 50. The new high bridge at Kent Narrows will be ready by next Memorial Day, and the remaining traffic signals to the east will be eliminated by 1992. All told, the state is spending about $80 million to improve Route 50 in this area.

Finally, even when construction is complete, travelers may wish to heed Gov. William Donald Schaefer's "Reach the Beach" advice and travel off-peak. Six lanes will be open from the Capital Beltway to Queenstown, but to accommodate everyone during the two-to four-hour period during which many would like to travel would require 10 to 20 lanes, which is neither feasible nor desirable. The State of Maryland is doing everything it can, but Mr. Snider and other travelers will still need to try to go early and stay late. HAL KASSOF Maryland State Highway Administrator Baltimore