Case One: Bob Morton of Hyattsville is driving to his downtown office along New York Avenue. As usual, he stops for the light at Bladensburg Road NE. Normally, after that, it's a smooth sail the rest of the way. But on this day, traffic is moving about as well as it does in a parking lot. The light at Montana Avenue is red four times as long as it's green. What's going on here?

Case Two: Jim Chatfield is motoring up Massachusetts Avenue NW to his home at the corner of Wisconsin. Normally, that drive is a pleasure, what with the elegance of the British Embassy and the shade trees beside St. Albans School. On this day, however, it takes Jim almost 20 minutes to inch the three-quarters of a mile from Rock Creek Park to his home. The lights, which normally are synchronized, aren't. Why?

Case three: Terry Dale of Northwest is driving east in the 1800 block of K Street NW. He wants to make a left turn at 18th Street, where a metal sign forbids lefts from 6 to 9:30 a.m. and from 4 to 6:30 p.m. But it's lunchtime, when lefts are supposedly legal. So Terry starts to whip the wheel of his BMW to the left when he notices the bright orange letters of a neon NO LEFT TURN sign. Wait a minute, says Terry. That sign is normally illuminated only during rush hours. What's it doing lit up at the wrong time?

According to Gary Wendt, all three of these puzzles can be laid directly at the door of a radio.

Wendt is the District government's chief of traffic operations, so poor traffic flow is his business. When traffic signals suddenly develop minds of their own, Wendt knows just where to turn.

"We have a radio down in our signal shop on G Street SE that controls the whole city," he explained. "The radio sends a beam out to the lights to synchronize them, and to change the No Left Turn signs.

"But the kinds of complaints you mention are a symptom of the deterioration of the system. It's been in place since 1959, and we're at better than a 20 percent malfunction rate."

What usually sends a particular signal haywire is its radio receiver, not the transmitter on G Street, Wendt said. It would be easy to replace a poor receiver if there were enough cash for a new one. But that isn't the way city budgets work these days, so Wendt must often steal from one part of town to resolve a mess in another.

Of course, that process is fraught with potential howling by citizens and politicians -- so much so that Wendt refused to say where he got the receiver that finally unraveled Bob Morton's New York Avenue tangle.

Help supposedly is on the way. "We've just embarked on a major program to upgrade the entire system," Wendt said. Price tag: between $23 million and $28 million. Timetable: finished by 1986, "assuming there are no breakdowns in the funding." Result: "If we get the whole system, and the money to maintain it, we won't have any more malfunctions."

In the meantime, Wendt offers cold comfort. "We are all just going to live with this," he said.