Fairfax County police prevented a Groveton man from jumping off the Woodrow Wilson Bridge during yesterday's evening rush hour, chasing him for more than a mile then talking him into climbing down from a lamppost on the bridge.

The 31-year-old man, whom police declined to identify, later admitted himself to Mount Vernon Mental Health Center for observation and "help with some family problems," a police spokesman said.

The incident began at 4:20 p.m. when a woman called police and told them her husband was on the bridge, threatening to jump.

Officer Douglas Graves, dispatched to the scene, said he saw a man leaning over the bridge rail. "He saw me and took off running. I went after him yelling, 'Stop, stop, I want to help you,'" Graves said.

The man ran to the Alexandria side of the bridge and led Graves on a mile-long chase through the Hunting Towers apartment complex and back to the bridge.

Officer Frank Cresswell, who had been talking to the man's wife at a neary motel, saw the chase, commandeered a citizen's car and drove past the two onto the bridge, then stopped, blocking rush-hour traffic with the car, and ran toward the man.

Caught between the two officers, the man climbed a few feet up a lamppost at the side of the bridge, which at that point is 70 feet above the Virginia shore.

"He seemed frightened of us," said Graves, "but when we assured him that he wouldn't be harmed or arrested, he said 'OK' and came down slowly."