Venezuela is in the midst of an electricity rationing programme caused, acording to the government, by acute water shortages at the main hydroelectric dam. As the BBC's Will Grant reports from Venezuela, the power cuts are leading to traffic chaos.
Drivers in the Andean city of Merida are having a tougher time than ever negotiating its chaotic streets. Now that the Venezuelan government's electricity rationing programme is under way, many of the city's traffic lights aren't working.
"It's horrible," says taxi driver Luis Sanchez. "The electricity can be off for up to seven or eight hours a day and the traffic lights in the centre have basically collapsed."
The darkness has caused accidents across the picturesque city as well as long tailbacks.
"Sometimes it can take as much as 20 or 30 minutes to get past a single traffic light, particularly if there are no traffic cops on duty," says Mr Sanchez. "No-one wants to let anyone else through."
In the Venezuelan Andes, the effect of the blackouts has been absolute says Jose Villet, the editor of the Cambio de Siglo newspaper in Merida.
"The government doesn't want the cuts to reach Caracas, so all of the pressure has been placed on three states in the Andes."
For a principally agriculture and tourism-based economy, Mr Villet says the daily energy-saving measures have been catastrophic.
"We've seen major losses in productivity in this state especially in food and coffee production. There are fewer tourists here too.
"Why would you go to a place where there's no electricity if you can take your holidays somewhere else? All in all, the regional economy has been badly damaged."
Added to the economic effects, the blackouts are also affecting the quality of life in the region.
Merida is an important centre of university education but many institutions are having to cancel classes.
Shopping centres and restaurants are often without power, and criminality on Merida's dark streets is on the rise.
In an effort to reduce the running costs of public buildings, the working day for state employees has now been cut in half.
And there has been a 200% increase in the sale of electrical generators, pumping out carbon monoxide into Merida's clean mountain air.
Dr Daniel Varnagy is an expert in electrical energy at the Simon Bolivar University.
"We're in a moment of deep crisis and it will be very difficult to reverse," he says.
"To construct another dam which is needed to generate more hydroelectrical power would take a minimum of three to five years.
"The alternatives, such as wind or solar power, just don't apply here with the scale of the problem."
The government of President Hugo Chavez says the current energy crisis is down to dangerously low levels of water in the country's main hydroelectric dam, Guri, in the south.
The Guri dam provides 70% of domestic electricity consumption. The water is around 10m below its normal level.
Jesus Farias is a former member of the Chavez government and one of the president's most vocal supporters.
"The problems at Guri are fundamental to this situation - it's a crisis of climatic conditions which is also being felt in other nations," says Mr Farias.
The government is doing what it can to alleviate the situation, he says, including flying cloud-bursting planes over the region to provoke rains.
"There are important investments being made to try to deal with this, but it's going to take time. Of course there have been mistakes, and the government has duly recognised them.
"But this is a temporary interruption in supply and within three or four months it will be solved," says Mr Farias.
But others - including Dr Varnagy - accuse the current administration of failing to read the warning signs.
"This is a problem which dates back over the past 20 years of government - 11 of which have been under President Chavez," he says.
"When he first came to office, I was part of a group of experts from the public utility companies which put together two proposals for his new government: maintenance of existing infrastructure and investment in new electricity generation and transmission.
"It would appear that those proposals were ignored."
At midnight in Venezuela, the national anthem is played on state television.
For many, it is now the moment when the televisions fall silent and the lights go off, the start of their four-hour energy rationing programme.
They are the lucky ones, for whom the cuts occur during the night rather than working hours.
Last week, President Chavez went on state television at midnight to announce that Caracas would be spared from the blackouts, minutes before they were due to start.
"There have been technical errors and poorly taken decisions," the president admitted, adding that he had sacked the country's electrical energy minister, Angel Rodriguez.
In September, Venezuelans go to the polls in legislative elections. The issue of electricity is expected to play a significant role in the vote, epecially as the blackouts come on top of other problems in basic infrastructure, such as water rationing, and a recent currency devaluation.
"Common sense tells you that there may well be a punishment vote against Chavez and the United Socialist Party," says Dr Varnagy.
"But you must remember that for many President Chavez is like a messiah and they will excuse this situation and continue to vote for him."
Meanwhile, the country continues to function as best as it can in the dark.
"You have to drive more carefully, especially at the crossroads," says Luis Sanchez from his taxi in Merida.
"I've seen accidents on almost every corner."