More than 630,000 high school seniors and graduates in South Korea took the state-administered annual college entrance exam Thursday, as the government implemented various traffic control and anti-noise measures near nationwide testing sites.

A total of 631,187 students, down about 10,000 from last year, registered to take the standardized College Scholastic Ability Test that was administrated at 1,212 testing sites, according to Ministry of Education.

The exam, which is similar to the American Scholastic Aptitude Test, is considered the most crucial test of students' academic careers and seen as the deciding factor in their choice of college and future professions.

The exam, which consists mostly of multiple-choice questions, is divided into five sections -- Korean language, mathematics, English, social and natural sciences, and a second foreign language.

The test started at 8:40 a.m. and was to run through 5 p.m., including lunch and breaks, the ministry said.

As in previous years, the government imposed various traffic control and anti-noise measures as part of efforts to ensure that the significant test was executed without any glitches.

Buses and subway trains extended their rush hour services by two hours to help all exam-takers arrive at the test sites on time, the ministry said.

The stock markets opened for trade one hour late, while government offices and enterprises in nearby areas also opened an hour later than usual to keep the roads clear for students on their way to the test centers, it said.

Police operated a temporary call center for students in need of a ride offering to transport them to the test centers by patrol car or on the back of a motorcycle.

Test applicants were banned from having electronic devices, including mobile phones, digital cameras, MP3 players, electronic calculators and smart watches, at their desks on concerns they might be used to cheat, the ministry said.

Second-year high school students gathered in front of testing sites in the pre-dawn hours to lend support to seniors taking the tests, waving placards reading "Jackpot!" and "Strength for You!"

"I arrived here at around 11 p.m. yesterday to get a good spot for cheering," said 17-year-old high school student Lee Seng-geun, singing a song for seniors with dozens of his friends.

Parents were seen waiting outside test centers or praying in Buddhist temples.

"I packed my daughter's favorite lunch," a 48-year-old mother of a test taker in Seoul said, adding that she will visit a temple later in the day to pray for her daughter.

Right after the beginning of the test, the government said it made the questions easier or similar to the previous year.

"This year's exam was similar to last year's," said Lee Jun-sik, head of the test development committee and a Chinese language and literature professor at Seoul's Sungkyunkwan University.

The education ministry will announce the answers to the questions on Nov. 23, and the applicants will be individually notified of their test results by Dec. 2. (Yonhap)