Bangladeshi police have fired tear gas to disperse tens of thousands of students protesting for an eighth day to demand safer roads after two teenagers were hit by a bus.

Key points: The demonstrating students stopped thousands of vehicles, bringing traffic to a halt

The demonstrating students stopped thousands of vehicles, bringing traffic to a halt The Government blamed the opposition for inciting protests

The Government blamed the opposition for inciting protests Critics claim the country's dangerous roads are due to corruption, cutting corners on safety

The demonstrating students stopped thousands of vehicles during the protests, including those of top officials, checking if the cars were registered and the drivers licensed.

They also blocked roads, only letting emergency vehicles through, and the Government has threatened to get tougher if the protests become too disruptive.

The US embassy criticised the crackdown on protesters who it said had "united and captured the imagination of the whole country".

The embassy tweeted that while it did not condone property damage by some of the protesters: "Nothing can justify the brutal attacks and violence over the weekend against the thousands of young people who have been peacefully exercising their democratic rights in supporting a safer Bangladesh."

Spontaneous student protests are rare in Bangladesh, and Prime Minister Sheikh Hasina suggested her political rivals were using the issue to stir up anti-government sentiment ahead of a general election this year.

Critics claim the country's unsafe roads result from cutting corners on safety. ( AP: AM Ahad )

Her party blamed the main opposition, led by Prime Minister Khaleda Zia, for using the student anger to create chaos for political gains. Political feuding between the two political leaders has dominated Bangladesh's politics for more than a decade.

The opposition Bangladesh Nationalist Party has denied involvement in the protests.

The angry school and college students demanded changes to Bangladesh's transport laws, paralysing the crowded capital of 18 million.

In response to the unrest, a law ministry official said the Cabinet will consider capital punishment for traffic accident deaths.

"In this amendment it has been proposed to award the highest level of punishment if it is killing by an accident," said the law ministry official, who has been briefed on the matter but declined to be named ahead of a decision.

The current punishment is a maximum jail term of three years. Using the death penalty for road accidents is rare anywhere in the world.

The Government also launched a week-long drive to check vehicle certificates in a bid to improve traffic safety, but said it would not tolerate more disruption by the protesters.

"Everything has an optimum point, and if anyone crosses the limit, action will be taken ... so don't cross the limit," Home Affairs Minister Asaduzzaman Khan said while inaugurating "traffic week" in Dhaka.

Students blocked the roads, only letting emergency vehicles through. ( AP: AM Ahad )

'Cutting corners on safety'

The roads of Dhaka are a web of gridlock and chaos. Unlicensed drivers, unregistered vehicles and speeding buses are commonplace, police corruption is rife and traffic enforcement often non-existent.

More than 4,000 people die in road accidents in Bangladesh each year.

According to the Accident Research Institute at the Bangladesh University of Engineering and Technology, pedestrian and passenger facilities are five time higher than driver fatalities in crashes.

Serajul Islam Chowdhury, a professor at Dhaka University, said it was common to cut corners on safety.

"Greed drives bus owners to appoint unprofessional and inexperienced drivers with low salaries, which in turn causes road accidents," he said.

Bangladesh has one of the world's highest rates of road accidents. ( AP: AM Ahad )

Separately, the car of outgoing US ambassador Marcia Bernicat was attacked by armed men, some on motorcycles, in Dhaka on Saturday, the embassy said in a statement.

"The ambassador and her security team departed the area unharmed ... however, two security vehicles sustained some damage," it said.

Police said they had not identified the attackers.

Reuters/AP