Drink-driving could increase if a Tube strike goes ahead on New Year's Eve, the chairman of London Assembly's transport committee has warned.
The Tube was due to run all night on New Year's Eve
Roger Evans also called for a no-strike agreement to keep London Underground (LU) running.
Union officials have rejected his drink-drive claim as "nonsense".
The 24-hour walkout by 4,000 staff is set to start at noon on 31 December. Station staff are planning a second walkout on 8 January.
Rail Maritime and Transport (RMT) union members voted five to one to strike in a dispute over staffing levels.
Last-minute talks on Friday between RMT officials and Tube chiefs failed to reach a deal through the conciliation service Acas.
Danger to Londoners
But Nigel Holness, LU service director, said there were plans for further talks on Thursday - two days ahead of the proposed industrial action.
Speaking to Radio Four's Today programme, Mr Evans said the strike posed a real danger to Londoners.
"There may be an increase in the amount of drinking and driving," he said.
"There will certainly be an increase in the number of illegal minicabs which are a problem we have in London.
"It just seems irresponsible for the union to call a strike for New Year's Eve."
But RMT general secretary Bob Crow said: "The only thing that causes drink driving casualties is people drinking alcohol and then driving, and it is absolute irresponsible nonsense to suggest that that could ever be anyone else's fault."
London mayor Ken Livingstone condemned the RMT for "trying to ruin New Year's Eve for thousands of Londoners" after the peace talks broke down.
The RMT fears LU plans, which include closing ticket offices, could lead to job losses and compromise safety.
Last December the RMT agreed a deal which would effectively create a 35-hour week for Tube station staff but RMT's General Secretary Bob Crow said LU was using the deal to "displace hundreds of safety-critical station staff".
The deal was something the RMT had campaigned for but LU said there were no plans to cut any jobs on the Tube.
Transport for London had already announced the continuous running of the Tube with the free period running from 2345 GMT on New Year's Eve until 0430 GMT on New Year's Day.