NEW YORK (Reuters) – New York City voters were voting on Tuesday to choose between Democratic Mayor Bill de Blasio and his Republican challenger, state Assemblywoman Nicole Malliotakis, with opinion polls showing the incumbent with a large lead.

De Blasio had the support of 61 percent of likely voters in the most recent Quinnipiac University poll, released last month, more than triple the 17 percent of respondents who backed Malliotakis, of the city’s Staten Island borough.

A truck attack early last week, in which an Uzbek man inspired by the Islamic State killed eight people on a bike lane, likely had little impact on voter preference in the heavily Democratic city, said Douglas Muzzio, a political science professor at Baruch College.

“He’s going to win big,” Muzzio said.

A progressive liberal, de Blasio in the past week campaigned with U.S. Senator Bernie Sanders of Vermont, an independent who backed de Blasio’s call for a state tax hike on people making more than $500,000 a year, a measure with little chance of passing the state legislature in Albany.

De Blasio’s chances are helped by strong disapproval in New York City for U.S. President Donald Trump.

Some 78 percent of respondents to the Quinnipiac poll disapproved of the way Trump is doing his job, with just 18 percent approving. De Blasio had a 58 percent favorability rating in the poll of 731 likely voters performed Sept. 27-Oct. 4, which had a 4.7-percentage-point margin of error.

Daisy Taberas, 71, said she voted for de Blasio due to her concerns over Trump’s stance on immigration. Taberas came from Peru as an immigrant 48 years ago.

“I like the way (de Blasio) works with children in the schools and he’s trying to protect the city and he cares about immigration,” Taberas said as she left a Manhattan polling site.

De Blasio has taken heat for increasing disruptions and delays on the city’s aging subway system, the largest in the United States, though he has emphasized that it is run by a state-controlled authority, not the city.

Malliotakis has criticized de Blasio over testimony from a former donor to the mayor in a federal corruption trial involving a union boss. The donor, Jona Rechnitz, told jurors he established a direct line to City Hall after raising money for the mayor’s campaign in 2013.

Federal prosecutors said in March they would not charge de Blasio, a point he has repeated on the campaign trail.