Fatal accidents on Hyderabad’s Biodiversity Park flyover raise questions over its design

HYDERABAD: CONTROVERSIAL FLYOVER DESIGN

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Deathtrap? The new flyover that has killed three people so far.

It was declared open with much fanfare on November 4, 2019 by K T Rama Rao, Minister for Municipal Administration and Urban Development (MA&UD). But the newly built uni-directional flyover connecting DivyaSree Orion to Biodiversity junction (popularly known as Biodiversity Park flyover) had to be shut down within a month following two accidents on the flyover resulting in three deaths. One horrific accident happened on November 23rd, when a driver failed to negotiate a curve and skidded off the flyover. The car crashed to the ground 20 metres below, crushing to death a hapless bystander and injuring six others standing underneath the flyover.

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That was the second such fatal incident, the first being reported on November 10th, within a week of the flyover’s inauguration, when an inebriated motorist, rammed his car into two persons taking midnight selfies on it. Both victims fell off the flyover on to the road beneath it and died instantly. Four other motorists were also injured in this accident.

Questions were immediately raised over the flyover’s design being the cause of the accidents. In its short distance of just 990 metres, Hyderabad’s first second-level flyover has two sharp curves, one midway towards the right and the second a little further to the left. The first curve occurs where the flyover reaches its maximum ground clearance of 18 metres where a driver is generally hitting the accelerator, making manoeuvrability of the vehicle’s direction a challenge. Greater Hyderabad Municipal Corporation (GHMC) Chief Engineer (Projects), R.Sreedhar stated that as per IRC guidelines, the steepest permissible curve is with 40-metre radius and there are two other flyovers at Nalgonda and Punjagutta in Hyderabad which have sharper curves.

“I travelled only once on the Biodiversity flyover when it first opened in November last year,” said Ramakrishna, a local resident. “I’m a very cautious driver but found myself pressing the accelerator while on it. Initially, I thought it was the excitement of driving on a near-empty flyover but while trying to slow down, I realised that it is actually the S-curve and the inclines on the flyover which were compelling me to speed. Post this experience, I decided to stay off it.”

Design controversy

GHMC officials, however, have been saying that the flyover’s design adheres to the Indian Roads Congress (IRC) norms. In 2016, M Venkata Rao Infra Projects Private Limited won the tender for the construction of multi-level flyovers/grade separators at four junctions, including the Biodiversity junction at an estimated Rs 379 crore. The firm, when questioned about the design of the flyover, pointed out that the two accidents that happened were due to drunk driving and speeding. Speaking to The News Minute, Nichal K, General Manager, M Venkata Rao Infra Projects Private Limited and Coordinator for the project, said, “The flyover is designed for a maximum speed of 60 and the suggested 40 kmph is a safe speed”.

The two sharp turns that some experts say are badly designed

An independent expert committee, comprised of structural engineers and road experts, has now been appointed to evaluate the design and safety aspects of the structure. They have suggested a slew of measures to contain the speed of vehicles on the flyover, which they inspected multiple times. The panel concluded that the maximum allowable speed limit is 40km/h and vigilant monitoring of traffic and commuters’ behaviour is needed for safe commuting.

However, speaking to the media, India Vice-President and Infrastructure Expert of Structural Engineers World Congress, Dr S.P. Anchuri said: “The structure is strong and durable but is very poorly designed. The increase and decrease of speed on a straight road will not affect the stability of a vehicle but when you have a curve and the vehicle is at high speed, there is a huge risk of skidding. There are two S-type curves, one after another within a very short distance on the Biodiversity flyover that are very risky. Even the 40km/h speed limit can be handled only by experienced drivers.”

Dr K M Lakshmana Rao, professor of transportation engineering at Jawaharlal Nehru Technical University, Hyderabad said there is a major fault with the alignment of the flyover. “For every curve, there should be a transitional curve which is missing,” added Dr Rao. “The starting point of the vertical gradient itself has been wrongly chosen. The location of ascent is too short and should be extended. There is supposed to be spacing between these two curves and this lack of this spacing leads to accidents. Also, the inner radius and the outer radius of the horizontal curve is non-symmetrical. If you let the driver opt for the inner curve, it leads to a higher risk of such accidents. There are multiple planning faults, and it should be rectified by providing higher railings with road safety rollers. It is unsafe even at 40km/h.”

“I personally feel that the flyover design wasn’t well thought out,” said K Kiran Chandra, a local resident. “You don’t anticipate cars flying off the flyovers if the roads are designed properly. The two curves in quick succession seem to be the issue.”

Some experts said that spatial dimensions and geometric alignment required for safe travel are completely lacking. Others have raised concerns about the height of the crash barriers. “The curves are very sharp and require proper signage that is visible from a substantial distance so that drivers are warned to reduce speed,” said Dr Kumar Molugaram, Professor of Civil Engineering and Transportation, Osmania University. “Stopping sight distance, braking distance, cone of vision, peripheral vision, turning path, acceleration and deceleration length are loopholes in the flyover”.

But according to GHMC, the expert committee panel took a test ride on the flyover on December 30 and expressed satisfaction over the measures taken. “There is no deviation or flaw in design”, said GHMC Commissioner D.S. Lokesh Kumar. “Administrative sanctions and technical approval for the flyover were taken for 40 km/h and it was based on the sanctions that the flyover was designed and built.”

Safety measures

The Biodiversity flyover was built as a part of the Strategic Road Development Plan (SRDP), which is a comprehensive transportation study (the SRDP is a self-financed project of the GHMC and relies on loans from external sources) for facilitating signal-free traffic in the city. But this statement was contradicted by Dr Ramachandraiah Chigurpati, Professor in Urban Studies, Centre for Economic and Social Studies (CESS), Hyderabad, who said, “We haven’t come across any comprehensive transportation study that recommended these flyovers under SRDP. In fact, SRDP is not based on any study. Also, the SRDP is aimed at providing more road space for private cars and does not address basic mobility issues in the city. Whatever flyovers and underpasses have been constructed so far (or are under construction) under SRDP are only for promoting private car use”.

To salvage the usage of the flyover, the four-member expert committee has proposed setting up a gantry sign at the beginning of the flyover, a map to guide the commuters, a restraint barrier with a series of plastic rollers over the curve to absorb the shock from errant vehicles, rumble strips, view cutters, side barriers, digital speed-limit signages, a dedicated lane for two wheelers, etc. But other experts said that since the design defects cannot be rectified now, any changes can only serve as precautionary measures. They also added that the new additions were likely to have a ripple effect on traffic jams along the Gachibowli-Miyapur main road and other connecting roads during peak hours.

Prof. Chigurpati observed: “I haven’t seen the roller barricades, hence not sure to what extent they would help. Rumble strips are useless in controlling speeds as I see them before U-turns on some main roads. Speed-breakers are the only way one can make the cars slow down. I don’t know why the traffic police is hesitant to put speed breakers on the flyover.”

Other experts, however, opined that putting speed breakers on flyovers, especially in the ascent, is not desired as a rule. The general tendency of motorists is to speed up after crossing speed breakers. Another problem with the recent measures is that two-wheelers need a minimum speed to balance, probably leading to more accidents where pillion riders become vulnerable to falls.

Will the recent measures actually curb speeding by motorists? There is now a ban on taking selfies on the flyover and a ₹1100 fine for exceeding the speed limit of 40 km/h. A significant number of cases have already been booked for speeding, dangerous driving and driving without helmet since the flyover was reopened barely 40 days after its closure.

Why these measures were not put in place before opening the flyover only the GHMC can answer. But on the larger issue of easing traffic congestion in the city, just building more flyovers is obviously not the solution.


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1 Comment

  1. Speed limits prescribed should be mandatorily imposed in the interest of all concerned. Empty throughways compel motorists to accelerate speeding — the argument is unacceptable. Curves cannot be a hindrance, as roads to hill stations have numerous hairpin curves on sloppy surfaces and motorists take all precautions to drive safely. Authorities, should bring same kind of responsibility on all motorists passing on the new bridge, for the safety of all road users. THINK RIGHT AND ACT RIGHT TOO.

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