Kolkata’s Chingrighata flyover is facing road-safety concerns. IIT-Kharagpur road-safety and transportation expert Bhargab Maitra identified reduced surface friction as a possible risk factor for motorcycles on its recently painted stretch.
According to multiple reports, Maitra identified several factors that could make the surface hazardous, particularly for two-wheelers. These include a mastic asphalt layer that is more than 13 years old, multiple layers of paint, the flyover’s curves and downward gradients, and inadequate surface friction.
Maitra reportedly said the ageing mastic asphalt layer had lost its effectiveness in providing the frictional resistance required for safe vehicle movement. Repeated coats of paint may have further reduced the road surface’s roughness, potentially affecting tyre grip.
Maitra added that repeated coats of paint had further smoothened the surface, improving its appearance but potentially reducing the grip needed for safe vehicle movement.
Why are two-wheelers more vulnerable?
According to the expert, motorcycles are more vulnerable to reduced surface friction because they have lower stability and a smaller tyre contact area. A loss of grip can make it harder for riders to maintain control, particularly while negotiating bends or descending sloping sections.
The risk could increase during drizzle, when wet road conditions may further compromise tyre traction. The combination of reduced surface friction, curves and downward gradients could make it more difficult for motorcyclists to maintain balance and control on the flyover. However, these factors alone do not conclusively establish that the paint caused the reported skidding incidents.
What steps have authorities taken?
Following the reported incidents, the West Bengal government installed rows of road studs at intervals of 10 metres on the rainbow-painted stretch of Chingrighata flyover. Authorities also roughened the surface of Gariahat Bridge by scraping it to improve friction.
Kolkata Police Commissioner Ajay Kumar Nanda said two-wheeler movement on the Chingrighata flyover would be prohibited during rain as a precautionary measure. He also said there was insufficient evidence to establish that the reported accidents had occurred because of the painting.
Urban Development and Municipal Affairs Minister Agnimitra Paul similarly said the administration had not conclusively established the cause of the skidding incidents.
Opposition questions safety of painted roads, Suvendu Adhikari orders probe
West Bengal Chief Minister Suvendu Adhikari has ordered a probe into the skidding incidents as opposition parties and an environmentalist raised concerns about the road-safety implications of the beautification drive.
Adhikari had said on Wednesday that there was no information to establish that the accidents were caused by the road painting. Urban Development and Municipal Affairs Minister Agnimitra Paul also maintained that anti-skid paints had been used on the flyover.
The controversy has triggered criticism from the opposition Congress, the Mamata Banerjee-led All India Trinamool Congress (AITC) and the CPI(M), which questioned the safety of painting road surfaces as part of a beautification initiative ahead of Durga Puja.
AITC calls painted flyover a ‘death trap’
The AITC criticised the administration over the reported skidding incidents, alleging that the freshly painted flyover had become dangerous during rainfall.
"The freshly painted flyover has turned into a death trap, with bikes skidding and accidents occurring at the very first spell of rain," the party said in a post on X, demanding accountability from Paul.
"The people of Bengal deserve safe roads, not dangerous infrastructure," it added, attaching video clips of the incidents.
The opposition has questioned whether the beautification initiative adequately accounted for road safety, particularly for two-wheeler riders travelling on wet surfaces.
The initiative is being undertaken ahead of Durga Puja, the first major festival season since the BJP came to power in West Bengal.
Congress flags risks of painting road surfaces
State Congress general secretary Ashutosh Chatterjee wrote to Paul and Kolkata Municipal Corporation Commissioner and Administrator Smita Pandey, raising concerns about the potential hazards of painting carriageways with conventional paints.
In his letter, Chatterjee argued that glossy paints should not be used indiscriminately on surfaces intended for motor vehicle traffic, as they could reduce tyre grip and increase the risk of skidding.
The CPI(M) also criticised the painting of flyover roads, with party leader Partha Pratim Biswas questioning the use of glossy materials on surfaces used by motorists and bikers.
"This is against road safety rules and violates the principles of road construction by using shiny glossy paint particles when it endangers the lives of motorists and bikers, particularly during rain," Biswas said.
The opposition's criticism comes amid questions about whether the materials used for the beautification work are suitable for carriageways exposed to regular vehicular movement and wet weather.
Environmentalist warns against glossy paint on roads
Environmentalist Somendra Mohan Ghosh told PTI that beautification efforts were welcome but should not compromise commuter safety. He said he had written to both Paul and Adhikari about the issue.
"I am worried; glossy oil paint on a motorable road is dangerous and should not be allowed. You can never paint the whole wheel-track area with ordinary house paint," Ghosh said.
He also warned that painting could conceal potholes, potentially increasing risks for commuters. According to him, peeling paint could eventually leave the road looking unattractive rather than achieving the intended improvement in appearance.
(With PTI inputs)