Merseytravel has unveiled plans to set up 17 park-and-ride schemes at stations in Liverpool, Knowsley, Wirral and Ellesmere Port.
The proposal would allow about 4,250 motorists to leave their cars out-side the city centre.
Plans for the first scheme, a 600-space car park at Sandhills station, are already in the hands of Liverpool council.
Steve Cook of Merseytravel said: "New park-and-rides in places like Aintree have filled to capacity very quickly.
"Between now and 2011, we will look at every station to see where we can expand our park-and-ride schemes.
"We already have a wishlist of sites which would provide another 4,230 spaces, although we might not achieve all of them. But in the short term, we hope to introduce about 1,600, starting with the Sandhills scheme, which has a three-minute rail link to the city centre."