The Fairfax City Council decided last night to let voters determine in the fall whether to sell $15 million in bonds to ease traffic problems at a bottleneck on Chain Bridge Road (Rte. 123), a major route through the city.

A referendum question on the city's November election ballot will ask for approval or rejection of a plan that would include widening part of Chain Bridge Road in the city from two lanes to four and rerouting some of its traffic in a new system of one-way streets.

The 5-to-1 vote came after a two-hour public hearing in which many city residents blamed Chain Bridge Road's traffic congestion problems on residents of surrounding Fairfax County. The road is a major cross-county artery, and many speakers argued that the county government should build a bypass to route traffic around the city. They characterized the bond plan as an attempt to appease the county.

For years, city officials resisted widening Chain Bridge Road, citing opposition to neighborhood disruption that the project would cause.

Council member Dorris H. Reed said last night, "There probably is no best way to handle the traffic, but I truly believe this is an approach that will help." Most council members said there still would be a major traffic problem but noted that there is no sign that the county will build a bypass.

Also, council members argued that growing commercial development in the city requires measures to expedite traffic.

Some residents warned of political consequences for council members who support the plan. Walter Stephens said he would campaign against any who support it.

The plan to go before the voters in the fall would widen Chain Bridge Road from two lanes to four between Kenmore Drive and Warwick Avenue near Rte. 50. Rust Curve, a winding, wooded stretch of Chain Bridge Road just north of the downtown area, would be unchanged. The curve has become a symbol of the small-town character of Fairfax City that many residents want to preserve.

To improve traffic flow while preserving the curve, Chain Bridge Road and the parallel University Drive would be converted to one-way streets from Judicial Drive to Kenmore Drive.

In addition, the $15 million bond issue would pay for extending Judicial Drive east to University Drive and for realigning Kenmore Drive to connect it with Layton Hall Drive. University Drive would be rebuilt to handle heavy truck traffic moving north along the one-way portion of it.

The lone vote against the referendum came from council member John Mason, who said a bypass around the city is needed and that the one-way system would disrupt traffic for city residents.

If approved by voters, construction could begin by 1989.