The Conservatives have cited a proposed congestion charge as a reason behind winning their first seat on a city council since 2012.
Mohamed Delowar Hossain won Tuesday’s by-election in the King’s Hedges ward on Cambridge City Council.
The vacancy occurred after Labour’s ex-deputy leader, Alex Collis, resigned over the plan to make drivers by tolls.
Mr Hossain said he wanted to “raise people’s voices about the congestion charge”.
Labour remains in overall control of the council.
Proposals for a sustainable travel zone (STZ), covering almost all of the city, have split residents.
The scheme has been put forward by the Greater Cambridge Partnership (GCP), a body that includes three local councils, including Cambridge City Council, businesses and the University of Cambridge.
The partnership is proposing that car users pay a daily charge of £5 if they drive within the STZ between 07:00 and 19:00 on weekdays, while van drivers would pay £10 and HGV drivers £50.
Before the poll, Ms Collis told the BBC that her opposition to the congestion charge was central to her decision to step down and she was concerned residents were not being listened to.
Mr Hussain got 622 votes and Labour’s Zarina Anwar got 598, with the Lib Dems’ Jamie Dalzell on 418 and the Green candidate Elizabeth May on 142.
He said he was strongly opposed to proposals for a congestion charge and said people he met on the doorstep had voiced concerns about the cost.
The Labour council leader, Mike Davey, said he was “disappointed” by the result.
The three councils have ruled out an official referendum on the plans to deal with traffic congestion, but the proposed charge was a key topic for many voters in the by-election and it is thought it was also key to results for the city council elections in May.
Although the Conservatives did not actually win any seats then, they got their highest vote share in recent years in every seat, and came very close to winning in a couple of wards after their consistent opposition to the STZ.
Those gains came as district councils in neighbouring Suffolk saw Green candidates increase their vote, and take outright control of a council in England for the first time.