A Montreal borough's effort to remind drivers that Sherbrooke Street West is one lane in each direction has been slowing traffic and confusing cyclists in the city's west end this week.

Notre-Dame-de-Grâce's busiest commercial stretch only has two traffic lanes between the Decarie Expressway and its terminus in Montreal West — one going west and the other going east.

During morning rush hour, curbside parking is nixed for an eastbound bus lane and the same is done in the westbound direction in the afternoon.

Aside from that bus lane, motoring side by side has always been against the rules along the three-kilometre stretch. However, the road's ample width and faded white lines demarcating parking spaces inspire some drivers to treat it more like a four-lane highway.

In an effort to encourage drivers to maintain a single-file line of traffic flow, Côte-Des-Neiges—NDG added parallel yellow lines down the middle of Sherbrooke Street on Tuesday night.

The new yellow lines stretch from NDG Park to the borough's westernmost border, replacing the single yellow line.

"Most of Sherbrooke in NDG is two lanes in each direction. One lane is for parking or buses and one lane is for traffic," explained Annalisa Harris, the borough's chief of staff.

"The yellow lines are to remind everyone of this."

Eastbound traffic, forced into a single-file by new road paint, backed up on Sherbrooke Street West Thursday morning with not place to pass. Buses continued to flow in the bus lane. (Sarah Leavitt/CBC)

The speed limit on Sherbrooke Street was lowered from 50 to 40 km/h a few months ago and borough officials noticed drivers passing those respecting the speed limit.

The yellow lines will soon have perpendicular lines added to the design, clearly showing that it is a no-drive (or cycle) zone, officials say.

Sherbrooke Street is one of the most-requested bike path locations in NDG and cyclist groups from across the city have been lobbying Montreal to add a protected path from Montreal West to Highway 25 in the east end.

Residents give mixed reviews

Resident Jordan Deitcher said the borough's initiative may have been easier for the community to accept were it done after all the roadwork on feeder streets is completed.

Side roads are clogged with construction, pushing drivers out onto the main thoroughfare and "now that Sherbrooke is narrower, it's creating more of a choke point," he said.

'I have no idea what they are for,' said Constance McGuire of the new yellow lines on Sherbrooke Street West in NDG as she drove through the Montreal neighbourhood. (Sarah Leavitt/CBC)

Niki Koulakis has watched the traffic on Sherbrooke for some four decades as she worked at the neighbourhood's popular Cosmo diner, just east of Draper Avenue.

"It won't help with traffic. In terms of bumper-to-bumper traffic, it'll just get more frustrating," said Koulakis.

But she's not totally against the idea, she added.

"I found it took the administration too long to do something simple like that — to show that it's only one lane on Sherbrooke Street. It will keep cars in order."

Constance McGuire was driving through NDG on Thursday and had no idea what the yellow lines were for.

"I'm not sure if I'm allowed in that lane. It's not quite two lanes but sometimes you can pull around if there's a car turning. Yesterday, I wasn't sure what I could do," she said. "I think it'll back up traffic even more, to be honest."