ELECTED leaders everywhere can draw a lesson from the past few months of political changes in Thailand: Pay attention to the obvious. One towering problem that Thai politicians overlook at their peril is Bangkok's traffic jams. Untold quantities of productivity, patience, and fossil fuels are incinerated in the city's legendary congestion. In July 2 elections, the reformist, technocratic party of former Prime Minister Chuan Leekpai lost its position as the largest in parliament, in part because frustrated Bangkok voters rejected them. Analysts say Mr. Chuan's administration grappled nobly with some of Thailand's structural problems - the growing economic disparities between urban and rural Thais, for example - but did not do enough to address more immediate concerns, like traffic. ''They made the mistake of ignoring the middle class in the cities,'' says Chalongphob Sussangkarn, an economist at the Thailand Development Research Institute here. Now a new administration is in power, and it is running into trouble over traffic. The new prime minister, Banharn Silpa-archa, has delegated the problem to two Bangkok-based parties in his coalition. But last month no less a figure than King Bhumibol Adulyadej criticized the government's inaction on the problem. The last time the much-revered king took such a prominent role in politics was to settle a violent clash between the military and pro-democracy protesters in 1992. Mr. Banharn has promised that he will achieve results in dealing with the capital's traffic, and has recently proposed staggered school hours and a four-day work week for bureaucrats. But his administration is drawing a lot more than just royal criticism. The victory of Banharn's Chart Thai Party is widely viewed as a triumph of the baht - the Thai currency. The party is based in the countryside, where vote-buying and political patronage are widely practiced. ''No one can deny that money-politics was influential,'' says Abhisit Vejjajiva, spokesman for Mr. Chuan's Democrat Party. Diplomats in Bangkok and foreign governments have expressed worries about the character of some leading members of Banharn's administration. In recent years, the US government has denied visas to three prominent Chart Thai members because of suspicions that they are involved in drug trafficking. Critics have also counted few technocrats in the Cabinet and attacked individual ministers for lacking expertise in their portfolios. ''This government never had a honeymoon period,'' says Prawase Wasi, a social critic who chaired a government commission on political reform. ''It began in a hot climate right away. Many politicians in the new government are accused of being local mafia and corrupt. So people don't trust them.'' The military, in a radio commentary on Aug. 25, criticized the government for not controlling inflation. Thai pundits saw this as an ominous sign since the military dominated Thai politics until the 1980s. The current scenario resembles a classic pattern in Thai politics: A new government comes in with grand promises, corruption and inefficiency produces a wave of criticism and frustration, and then the military enters the picture in the name of restoring order. The difference with the Banharn government is that it is all happening so quickly. Even so, analysts and generals say the military is now more interested in participating in the national debate than in seizing power. Banharn has promised to promote political reform in order to break this cycle and has pledged to heed the work of Dr. Prawase's Democratic Development Committee. ''We realized that the Thai system is very defective,'' Prawase says. ''It's very easy for [certain people] to spend money to get elected along with their colleagues. They then become a group of ministers. You don't have to have knowledge or honesty. Their work is unchecked. Nobody can do anything about it.'' The result, he concludes, is that ''Thai people are very frustrated. They want change but they don't know where to go.'' The recommendations made by Prawase's committee include rewriting the Constitution by nonparliamentarians, a feature that Thailand's elected representatives view warily. Banharn has appeared to back away from his commitment to political reform in recent weeks, but that may be because of more immediate concerns, like addressing the king's criticism over traffic management. Nimit Nontapunthawat, an executive vice president at Bangkok Bank, says he appreciates what former Premier Chuan has tried to accomplish. But ''he disregarded problems that really make people's lives difficult, like traffic jams,'' Mr. Nimit says. It takes him 3 and 1/2 hours a day to commute the 12-mile round trip from home to office. Assuming Banharn's government withstands all the criticism and stays in place, the new leader is apparently trying to avoid repeating Chuan's oversight.