WASHINGTON - With a deadline looming for a cutoff of highway aid to states, Senate Republicans failed Tuesday to muster enough votes to take up a bill that would extend transportation programs for six years.

Democrats complained they'd had only an hour to read the 1,040-page bill. Senate Majority Leader Mitch McConnell, R-Ky., said he would give Democrats more time, but added he intends to push forward with the bill even if it means keeping the Senate in session over the weekend.

A motion to begin debate failed 41 to 56, falling far short of the 60 votes needed.

Sen. Charles Schumer of New York, the No. 3 Democratic leader, said, "I can't remember a time where I have been asked in all my years in the Congress to vote yes ahead of time on a bill we haven't seen, and there are no amendments" allowed.

While the bill would authorize highway and transit programs for six years, it contains only enough money - about $47 billion, according to a list of offsets supplied by McConnell's office - to close the current funding gap for transportation programs for three years. The government currently spends about $50 billion a year on highway and transit aid, but the federal gas tax and other transportation taxes and fees raise only about $35 billion a year.

Some Republicans also expressed unhappiness with the bill. Banking Committee Chairman Richard Shelby, R-Ala., said he objected to one of its money-raising provisions that would reduce the dividend that the Federal Reserve pays to member banks, worth $16.3 billion.

"You're taking money and there's no connection between small banks, medium-sized banks and building highways and transit and you're going to weaken the banking system. I'd be against that," he told reporters.

The banking provision is the biggest source of money in the legislation to pay for transportation programs, according to a list provided by McConnell's office. Another $9 billion would come from the sale of oil from the Strategic Oil Reserve, the nation's energy stockpile for emergencies. Indexing customs fees to rise with inflation would raise $4 billion. Extension of Transportation Security Administration fees paid by airline passengers would raise another $3.5 billion.

Sen. Richard Blumenthal, D-Conn., called the bill "a black hole." He said Democrats have been told changes have been made to auto, trucking and rail safety provisions that were agreed to last week on a party-line vote by the Senate commerce committee, but no details were provided before the vote. Some Democrats have described the provisions as giveaways to industry that would undermine safety.

Safety advocates poring over the bill text late Tuesday said some of the controversial provisions were "tweaked," but remain in the bill.

One provision allows some states to effectively reduce the eligible age for an interstate commercial truck driving license from 21 to 18. The trucking industry says more drivers are needed to relieve a shortage.

The bill would also prevent the public from seeing the government's safety ratings of truck and bus companies. The trucking industry says the government's methodology for the ratings is flawed.

Congress faces a July 31 deadline to act. That's when authority for transportation programs expires, eliminating the Transportation Department's ability to process promised highway and transit aid payments to states.

But simply renewing the department's authorization isn't enough. Without an infusion of cash, the balance in the federal Highway Trust Fund is forecast to drop by the end of the month below $4 billion, the minimum cushion needed to keep money flowing to states without interruption.

The House last week passed its own $8 billion bill keep transportation programs going until Dec. 18 while lawmakers try to work out a longer-term funding plan. But McConnell has said that he wants to pass a bill that keeps programs going at least through next year's presidential election, if not longer.

"I think the Senate should take up our short-term bill as is, and pass that," House Majority Leader Kevin McCarthy, R-Calif., told reporters. He said "everyone" wants to pass a long-term bill, but a better bill might be achieved with more time.

Congress has passed 34 temporary extensions of authority and financial bailouts of highway and transit programs since 2009. The uncertainty over federal aid has caused several states to delay or shelve transportation projects.