Perth's daily traffic congestion battle has pushed nearly two thirds of residents to rethink their commute, a new survey has found.

Traffic congestion heading into Perth's metropolitan area during morning peak hour reduces a vehicle's average travel speed to 52.5 kilometres an hour - 10 kilometres slower than five years ago.

Perth's congestion problem cost the state government $1.7 billion in 2016-17.

The city has one of the highest car use rates in Australia with four in every five workers choosing to drive to work, but according to a survey conducted by HERE Technologies, two thirds of those people were starting to reconsider their daily commute.

"Half of travellers [who are rethinking their commute] are favouring alternate modes of transport or changing their travel routes, while some savvy commutes rely on real-time traffic updates before selecting their mode of transport or driving route," the report said.