Kolkata’s Chingrighata flyover is facing renewed road-safety concerns after an IIT-Kharagpur expert identified reduced surface friction as a possible factor behind motorcycles skidding on its recently painted stretch. Police have introduced speed-control measures and KMDA has begun removing the paint to restore grip, while two-wheelers will be stopped during rain.
Road-safety and transportation expert Bhargab Maitra inspected the flyover and identified a combination of factors that could make the surface hazardous, particularly for motorcycles. 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.
“The mastic asphalt layer is more than 13 years old and has lost its effectiveness in offering the required frictional resistance. Multiple layers of painting have further reduced the roughness. With every layer, brightness has improved but friction has been compromised,” Maitra said, according to the report.
The expert noted that two-wheelers are more vulnerable because they have lower stability and a smaller tyre contact area. The risk increases on curved and sloping sections, especially during drizzle. Police said motorcycles were being allowed on the flyover after corrective work and an inspection, but advisories and restrictions remained in place.
Lalbazar police officials said the strategy would now focus on reducing motorcycle speeds throughout the day rather than limiting their movement only during rain. Signage has been installed, traffic entering the flyover may be staggered, and a 40-kmph speed limit has been recommended. Police are also considering stricter enforcement, including speed cameras.
The issue has been complicated by viral videos of riders skidding on the painted surface. The flyover has reportedly become a destination for bikers attempting to record reels, prompting the deployment of civic volunteers. Volunteers are discouraging riders from stopping, slowing abruptly or filming while negotiating the curve. Police said two-wheelers would continue to be stopped completely during rain.
Maitra also recommended replacing the ageing mastic layer and carrying out safety audits of all city flyovers every six months. Police said none of the riders involved in the viral skidding incidents on Wednesday had approached them, limiting the scope for an accident-specific investigation.
KMDA has started manual and mechanised removal of the paint to restore the road’s surface roughness. Environmental activist SM Ghosh and other citizens have sought written clarification from the paint manufacturers on whether the coating used was road-grade thermoplastic material and whether the prescribed application standards were followed. The immediate measures now involve paint removal, speed regulation and continued monitoring of motorcycle movement on the flyover.
