Flawless autobahns and punctual trains are as much a part of Germany’s image as Beethoven and Goethe. But the country’s famed infrastructure is starting to crumble.

The once-soaring bridges are sagging. Some railroad switching equipment, once top-of-the-line, has not been updated since the time of the kaisers. Well-engineered canal locks are succumbing to silt and neglect.

Germany’s network of roads and railroads is one of the densest and most developed in the world. But bottlenecks are starting to crimp Germany’s export-driven economy, experts say. Even maintaining the status quo will require nearly doubling current spending levels, according to a recent report issued by a government commission.

Peter Osse, a shipper in the port of Hamburg, said he increasingly reaches not for a timetable but a prayer book when he makes transportation plans.

Osse’s hundred-year-old warehouse is at the center of a port through which much of Germany’s exports are shipped. But next year, Hamburg’s soaring Köhlbrand Bridge, which joins the city’s port to its mainland, will undergo major reconstruction, cutting the number of lanes from four to two for much of the year.

“In the near future, we will have a crisis,” Osse said in a cramped dockside office littered with shipping manifests and memorabilia from the local St. Pauli soccer club. He said transportation is already far slower than it was 20 years ago.

“We don’t have many possibilities,” he said. So he was resorting to a higher power, he said. “My family and I go to church.”

As Chancellor Angela Merkel heads into her third four-year term, calls are growing for her to do more to address a problem that some officials say is speeding out of control.

“Germany is the second-largest of the world’s exporting nations, but only if our transport system is functioning,” said Kurt Bodewig, a former transportation minister. “If not, our economy will be in a dangerous situation.” Bodewig led a federal commission that recently recommended that Germany spend $9.7 billion a year more on infrastructure just to maintain its current network. Merkel’s new coalition plans to increase spending by a fifth of that.

The problems started at the time of German reunification in 1990, experts say. The government poured vast sums of money into the former East Germany, where some roads and railways had barely been maintained. Now much of the eastern countryside has sparkling new highways, but not many people to drive on them — Germany’s population and industry have moved westward. Infrastructure in the richer, western half of Germany, meanwhile, has been neglected.

Now, nearly half of Germany’s municipal bridges and one-fifth of its highways are considered to be in poor condition, according to federal data and a study by the German Institute for Urban Affairs. In 2011, the most recent year for which figures are available, Germany spent 0.6 percent of its gross domestic product on building and maintaining inland transportation infrastructure, according to the Organization for Economic Cooperation and Development. That was less than France, Britain, Canada and many others in the developed world.

And the quality of Germany’s infrastructure has been slipping in international rankings. Germany placed 10th in the world in 2013 in terms of quality of overall infrastructure, according to surveys by the World Economic Forum, down from third place in 2006. The United States was ranked 19th in 2013, down from eighth in 2006.

“There will be changes if we do not solve this problem — that’s for sure,” said Gunther Bonz, president of the Hamburg Port Business Association. “If you do not invest now, in 10 or 15 years from now we will have a situation as we do in Southern Europe,” where infrastructure is in worse shape than in Germany.

Constricting the available money, the German government has been pursuing self-imposed austerity policies, restraining its borrowing and spending to balance the budget — an aim that will be reached next year. The U.S. Treasury Department and the International Monetary Fund have blasted Germany, arguing that it relies too heavily on exports and not enough on domestic demand to sustain its economy — making it far harder for its struggling neighbors to recover.

Spending more money on infrastructure would be a classic way to stimulate the domestic economy. But in a nation whose language uses the same word for “debt” and “guilt,” the efforts to restrain borrowing have broad political support.

Still, a growing number of critics say that borrowing to invest in infrastructure in the name of ensuring economic growth is different from borrowing to pay day-to-day expenses such as salaries or pensions.

And some say there are other ways to boost money for transportation, such as tolls.

“If you increase investments in streets, bridges and railroads, you obviously are encouraging domestic consumption,” said Klaus-Peter Müller, chairman of the German Traffic Forum. “After all, everybody is yelling at the Germans to do more at home, so let’s do it,”

More money would help avert incidents such as one in December 2012, when authorities suddenly closed a major bridge over the Rhine outside Cologne to trucks for three months, snarling traffic and causing chaos within Germany’s transportation system. It cost the German economy between $83 million and $110 million, according to a study commissioned by the Initiative for Traffic Infrastructure, an industry group that advocates for more investment in roads.

A McKinsey & Co. study in 2013 estimated that Germany needs to invest $69 billion in its roads to meet expected demand in the coming years.

“Germany in five or 10 years will not have the same standard of infrastructure it has today,” said Reinhard Mayer, the minister in charge of transportation in the north state of Schleswig-Holstein. Without further investment, he said, “we must live with infrastructure where bridges are not working. Or, for example, the Kiel Canal with its locks not working. And that’s not very funny for such an important economy as Germany.”