A viral video showing three motorcycles skidding on Kolkata’s rainbow-painted Chingrighata flyover after a drizzle has triggered a road-safety inspection by state and civic agencies, putting the spotlight on whether the decorative surface meets wet-weather grip standards.
Senior state minister Agnimitra Paul said the Kolkata Metropolitan Development Authority, police and civic engineers had been sent to the flyover to examine the incident and the materials used for the painting. She told The Times of India that the rainbow treatment was applied for the festive season and was not intended to be permanent. “We will take steps as per recommendations of the experts,” Paul said.
The exact circumstances shown in the viral footage have not been independently established. The video appears to show three motorcycles losing control on the painted section after light rain, but the report does not establish whether the surface coating was the sole cause of the skidding.
Chief minister Suvendu Adhikari also declined to draw a conclusion without further information. “Bikes can skid for various reasons. I will not make any statement without knowing what has actually happened,” he told reporters.
The immediate technical question is whether the painted surface was designed for traffic and wet conditions. A senior engineer associated with the West Bengal Traffic and Transport Planning Directorate questioned whether the authorities had used road-grade, skid-resistant material or ordinary decorative paint. The engineer said the surface appeared more like oil-based or emulsion paint than thermoplastic road-marking material, while stressing that road surfaces require technically approved products.
Road engineers cited in the report said tyre grip depends on friction between rubber and the textured road surface. A smooth coating can cover some of the asphalt’s microscopic irregularities, potentially reducing friction. When water accumulates on the surface, braking and cornering can become more hazardous, particularly for two-wheelers.
An engineer with the National Highway Authority of India said specially formulated coloured surfacing systems containing anti-skid aggregates can provide adequate friction in wet conditions. However, engineers also cautioned that thermoplastic paint is not automatically suitable for covering an entire carriageway. Large decorative applications require appropriate coloured surfacing systems and separate friction assessments.
The episode has also revived questions around the treatment of mastic asphalt surfaces, although the supplied report does not establish whether the flyover’s existing surface contributed to the incidents. The distinction between road marking and full-surface colouring is significant because a material suitable for lines or symbols may not be suitable for a broad traffic-bearing area.
Kolkata Police and Bidhannagar Police said they had not received complaints about the incident at the time of the report. A senior Kolkata Police source said the agencies involved in the painting had been informed that the treatment could be dangerous.
The inspection by KMDA, police and civic engineers is expected to determine the material used, assess the surface’s grip and guide any corrective action. The authorities have said decisions will follow the recommendations of the experts examining the flyover.
