"This is one of our options, because the decision is unconstitutional.
"We are looking at different options," Congress of SA Trade Unions Gauteng secretary Dumisani Dakile said on Friday.
"One of the other options is to carry on [with the strike], but we are still discussing this."
The Johannesburg Magistrate's Court on Thursday night dismissed Cosatu's application for a highway motorcade.
Cosatu had approached the court after failing to get permission from the Johannesburg metro police.
Cosatu spokesperson Patrick Craven said after the ruling they intended going ahead with the protest.
Provincial chair Phutas Tseki said on Friday the trade union federation would assess the court ruling.
"All we are going to do will be done in the confines of the law."
Dakile said on Wednesday that the motorcade had been planned for the M1 north, N1 south, N12, and M2 north highways in Johannesburg.
The N3 highway was briefly closed in December when protesting motorists parked their cars and danced during a similar drive-slow motorcade.
Interim order
On April 11, the SA National Roads Agency Limited (Sanral) announced e-tolling would be rolled out in Gauteng within the next two months.
In April last year, the North Gauteng High Court granted the Opposition to Urban Tolling Alliance (Outa) an interdict halting implementation of e-tolling pending a full judicial review.
Sanral and the National Treasury appealed the court order.
In September, the Constitutional Court set aside the interim order. In December the High Court in Pretoria dismissed Outa's application to scrap e-tolling.
On January 25, the court granted Outa leave to take the matter to the Supreme Court of Appeal (SCA) in Bloemfontein.
The SCA hearing will take place in September.