The plan faced resistance due to budget concerns and protests by local shopkeepers who were worried about the effect on sales.

The police have also hampered the park scheme, citing traffic problems it would cause.

The flyover, which is 17 meters above ground, has connected the city center to the western region since the 1970s.

As decades passed, however, it was assessed to be too old to sustain. It received a “D” grade in a safety test in 2006 and was recommended to be demolished in a few years, prompting the mayor to pledge to remodel it rather than tear it down due to its historical significance.

To open the park in early 2017 as scheduled, the city planned to start restricting the flyover traffic, demolish the old sections of the road and initiate the reinforcement operation from this month.

By law, the city government can discretionally tear down construction or control and restrict the traffic if there are public safety risks.

In order to minimize the potential traffic congestion near the flyover, Seoul City sought approval from the Seoul Metropolitan Police Agency more than six months ago for installing five new traffic signals around the flyover.

The police, however, put the proposal on hold twice -- in July and August -- citing insufficient backup plans, which Seoul City has said is “regretful.”

“The city cannot help but raise ‘reasonable’ suspicion that the police made the decision with a political motive,” said Seoul City spokesperson Kim In-cheol in early September.

“While the city has actively discussed the traffic measures with the police at the working level since October last year, the police suspended the review over practically trivial matters that can be easily improved.”

Some raised speculation that the police action was influenced by the central government to contain Park who is considered a potential presidential candidate from the main opposition party.

“The overpass was graded D again in 2012, with only two to three years of time left. It’s necessary to tear it down no later than this year,” said a Seoul City official said.

The police flatly denied the claim, claiming that it was merely the city’s interpretation.

Safety concerns arose in January last year after one of the flyover’s concrete floor plates fell to the ground. Over 93 percent of the 220 supporting structures of the flyover were graded the lowest level “E” last year, officials said.

The police then asked the city in September to get the opinion of the Transport Ministry, saying that the decision to change the traffic routes is under its discretion.

The ministry, however, referred back to the police, refusing to get involved.

The police on Tuesday reiterated that they would review the new traffic signal plan once the city receives the ministry’s approval.

Regardless of the “Seoul High Line Park” plan, Seoul City said it would restrict the overpass traffic and partially tear down the structure from next month on its own authority, citing safety concerns.

The potential traffic congestion problem is expected to remain until the tug-of-war between the city and the police is resolved.

By Lee Hyun-jeong (rene@heraldcorp.com)