In the first major test of whether Congress will abide by the self-imposed austerity of last year's budget agreement, the Senate is taking up one of the biggest public works bills in the nation's history, a multiyear plan laden with big-ticket highway and transit projects that are dear to every lawmaker's heart.

The measure, scheduled for debate Monday, calls for spending at least $181 billion, and possibly much more, over six years on virtually every type of land transportation project, from roads to bridges to subways to bike paths.Every congressional district in the country stands to gain something from the measure, but the big question will be which ones gain the most. Regional alliances have formed, pitting senators from the Northeast and parts of the West, whose states benefit most from current transportation policies, against Southerners who want to revamp the entire system to send more money their way.

And throughout the debate, deficit hawks in both houses will be fighting to hold down the size of the spending package, attempting to ward off lavish pork-barrel projects and to safeguard the nation's first balanced budget in three decades.

Many members of the Senate's Republican majority are planning to use the bill as a vehicle to raise partisan side issues, any one of which could trigger a lengthy floor debate or cause a confrontation with the White House. Among the approximately 200 proposed amendments are measures to delay new clean-air regulations, scale back affirmative-action programs and weaken labor protections for construction workers.

The main House proposal calls for spending $218 billion on highways and mass transit over six years. The House is not expected to take up that bill for several weeks. The main Senate proposal would spend $181 billion over the same period, but there are negotiations among Senate leaders to increase that amount by $24 billion.

The bill would replace the landmark Intermodal Surface Transportation Efficiency Act of 1991, known as ISTEA.