Dorothy Thornhill’s comments come after it was announced that the train operating company would be carrying out a traffic study survey following concerns that the station’s redesign has caused problems.
London Midland has been criticised since it finished the £1.3 million redesign of the station last year.
The revamp saw the station’s drop-off bays being removed from the Station Road entrance and a new short stay car park created off Woodford Road.
However, the new arrangement has seen drivers dumping passengers off in front of the station in moving traffic rather than using the new car park.
The redesign also saw the taxi rank removed from the front of the station so it could be pedestrianised and repositioned along the access road to the station’s car park.
Mayor Thornhill said London Midland had been warned about the potential problems before it redeveloped Watford Junction.
She said councillors had had reservations about the lack of a drop-off point at the front of the station and those fears had been vindicated by the current problems.
"When we were consulted councillors, such as (Watford central and Oxhey county councillor) Stephen Giles-Medhurst, were very vocal about saying it would not work without a proper designated drop-off.
"And so it has proved to be. You can’t have one of the busiest stations in the country with no proper taxi rank and no proper drop-off."
The video study of traffic movements around the station is due to start next week.