Conservative senators are leading the charge to water down legislation aimed at cracking down on impaired driving.

The Senate's legal and constitutional affairs committee has voted to delete a provision from Bill C-46 that would authorize police to conduct random roadside breathalyzer tests, without needing to have reasonable grounds to suspect the driver may be impaired by alcohol.

The move was proposed late Wednesday by Conservative Sen. Denise Batters on the grounds that the provision is likely to violate the charter of rights and would, therefore, be struck down by the courts as unconstitutional.

She won the backing of four other Conservatives senators on the committee, as well as the committee chair, Liberal independent Sen. Serge Joyal, a constitutional expert in his own right.

Five independent senators voted against deleting the provision, including Sen. Marc Gold, who is also a constitutional law expert, while one other Liberal independent abstained.

C-46 is a companion bill to government legislation to legalize recreational marijuana; however, the provision the committee voted to delete is meant to apply only to alcohol impairment.