A ride from BT Road to Bagbazar along the Lockgate flyover takes about three minutes.

The same ride on Tuesday took Metro 27 minutes along one of the alternative routes proposed by Lalbazar for the period when the Tallah bridge is demolished and a new structure comes up.

This was during afternoon when traffic was not heavy, according to police.

The alternative route — Chiria More to Bagbazar via Cossipore Road and Khagen Chatterjee Road — is about 3km.

Cossipore Road runs through the Cossipore bridge, a structure that reeks of neglect with iron rods coming off concrete railings, and then meanders down a stretch lined with godowns, truck depots and a railway yard from where heavy trucks keep moving in and out.

Footpaths on either side are hardly visible except for stretches with temples or trees with concrete bases.

The Tallah bridge will be closed to traffic from January 31 midnight to make way for demolition of the 57-year-old structure.

A committee formed to run a health check on bridges and flyovers in the city had said the bridge was unsuitable for vehicular movement.

The demolition of the bridge is scheduled to start on February 1 and PWD engineers have said it would take close to three years for a new structure to come up.

The city police have worked out a series of diversions to accommodate traffic headed to and from the five-point crossing in Shyambazar.

As part of the plan, the Lockgate flyover will remain one-way throughout the day. That means only vehicles from Sovabazar or Bagbazar will be allowed to use the flyover to reach BT Road.

Residents of the area said on Tuesday that neither Cossipore Road nor Khagen Chatterjee Road was ready for a sudden surge in vehicle count. A two-way movement of traffic on the flyover would have made travel easier, they said.

The police have ruled it out saying it would be “risky on a narrow road”.

The alternative, though, has left people worried.

“Cossipore Road, which has seen a rise in the number of heavy vehicles, has been struggling to accommodate vehicles for the past few years,” Janaki Prasad Shaw, who runs a stationery shop near Cossipore fire station, said.

“If more vehicles are diverted through this road, nothing will move. How will you restrict trucks from entering or leaving the rail yard?”

There were a few trucks in the afternoon on Tuesday but buses and minibuses, along with small vehicles, were aplenty.

Tin shades, wooden windows and tree leaves were covered in a thick coat of dust as some workers laid water pipes on one side of the road.

Most buses and minibuses headed for the five-point crossing from Dunlop used to take the Tallah bridge from BT Road. Khagen Chatteree Road and Cossipire Road are used by a few buses and minibuses, mostly on the Belghoria-Howrah fire station, Dunlop-BBD Bag and Cossipore-Esplanade routes.

Small vehicles, especially cars, rarely use Cossipore Road, just about 7m wide.

“Neither Khagen Chatterjee Road nor Cossipore Road has any footpath. Most of us prefer walking down the two roads even if it is risky,” Rupesh Tiwari, a Cossipore resident, said. “If the diversion starts from February 1, cops need to ensure road safety for pedestrians.”

Footpaths on Khagen Chatterjee Road have been gobbled up either by rows of shops or converted into spaces for parking trucks.

On Tuesday, this newspaper found new iron railings being installed in a few places where there was some semblance of a footpath. At some places, workers laid paver blocks for a footpath. Parents kept crossing the road with their children returning from schools. Young and old stood on the road to board buses in the absence of bus stops.

Signal posts were missing on both Cossipore Road and Khagen Chatterjee Road.

The result: chaotic traffic as a handful of cops, their faces covered with handkerchiefs, looked on.