"Capital en Movimiento" the city declares itself, next to a wind-blown drawing of its main landmark, the Angel of Independence. On many days, however, this capital is not in movement at all. Since the city does not regulate protests, demonstrators are free to block traffic whenever they please. In the first three months of this year alone, there were 740 street demonstrations, an average of about eight and a half a day - an improvement over last year, when there were more than nine a day, the city government points out. "In our country, it is a constitutional right to demonstrate," said Juan Jos Garca Ochoa, the leftist city government's point man for protests. The daily marches may appear to be a sign of a vibrant democracy, proof of a wealth of ideals and opportunities to express them. But they also obey the choreographed rules of engagement laid down during 70 years of rule by the Institutional Revolutionary Party, known as the PRI. "For many years, the political system was very closed, but it was not authoritarian," Garca Ochoa said. "During 70 years of the PRI, they let you demonstrate as long as you didn't threaten their hold on power." It has been a decade since opposition parties broke the PRI's political monopoly, but the idea that the best way to get the authorities' attention is to stop traffic remains embedded in Mexico's political culture. The dynamic is so entrenched that the city runs a daily internet alert, noting what groups are scheduled to protest, whether they are likely to disrupt traffic and dispensing advisories to commuters. "Take precautions" is a common one. Rather than respond to demands "officials bet that people will wear themselves out physically, economically and psychologically", said Renato Consuegra, a political consultant who works on media strategies for civil groups. "Unfortunately, protests are the only channel citizens have to make themselves heard." The city government argues that the number of marches is falling because officials are working to address local grievances. A dozen years ago, there were about 20 demonstrations a day, Garca Ochoa said. But the local government, he argued, is powerless to resolve the problems that bring marchers by the busload from other states, looking for a hearing in the capital. Garca Ochoa spends part of every day on the phone with federal officials, trying to persuade them to meet with protesters from outside the city.Ral Nava, an opposition legislator, has so far failed to persuade the city assembly, dominated by the leftist Party of the Democratic Revolution, to consider regulating marches. "You have to respect the rights of the majority," he said. "The cost does not even count the accidents and the injured who don't get to the hospital on time." The city government and its allies in the assembly argue that free speech is paramount and that regulating marches would not deal with the problems behind them anyway. But Mayor Marcelo Ebrard finally lost some of his cool last month. After sacked electricity workers blocked traffic for a day on the main north-south artery, Insurgentes Avenue, he said the union's leader had to understand that the city's residents "shouldn't have to suffer". The electricity workers certainly have been persistent. They have demonstrated more than 860 times since the federal government shut down their state-owned company last October, the city says. The damage has been estimated at more than 490 hours of blocked traffic. Even some protesters admit that their marches ensnare the innocent and uninvolved. Last week, several hundred students who failed to win places at one of Mexico's main public universities strode down the main avenue, Paseo de la Reforma, then zigzagged through the narrow streets of the historic centre to rally outside the Education Ministry. "If you present a commission of five people to an office like this, they won't pay attention," said Armando Gonzlez, 19, who wants to study law, gesturing at the Education Ministry. "But if you put some pressure, they have to attend you." Occasionally, a protest is so disruptive that the city issues a news release to explain its attempts to negotiate an end. So it was a number of weeks ago, after a group of about 13,000 men, women and children from the poor and very distant suburb of Chimalhuacn came to Mexico City to protest about the annual flooding during the rainy season, when sewage overflows onto the streets. Elsewhere in the city that day, a group of mostly blind street vendors had marched to City Hall. Fifty people in the far south blocked streets to demand electricity service. Taxi drivers angry about something had camped outside the city transport office. And, of course, about 200 electricity workers blocked the main westbound artery for an hour. "We come here every time; they don't pay any attention to us," said Asuncin Corts, 56, a cleaner who was forfeiting a day's wages in Chimalhuacn. As for the inconvenience to Mexico City residents, she shrugged. "It doesn't matter to us because they have everything here and we are poor," she said.